Marshmallows

Ever wonder how marshmallows got their name? They were originally made from the root of the marsh mallow plant, whose sap was whisked with sugar to create a foam. Modern marshmallows use gelatin, which is far easier to procure than fresh mallow root. I like to use egg whites, too—far closer to the Italian meringue we covered earlier (see page 293)—but if undercooked egg whites aren’t your thing, leave them out.

Marshmallows are a classic example of foam colloids. They start as liquid foams: when fresh, the mixture will flow and change shape. After 12–24 hours, they set into a solid foam that has a memory of its shape. They’re elastic: you can press them, but when you let go, they rebound to their original shape.

In a small bowl, mix 3 tablespoons (21g) unflavored gelatin powder (3 envelopes) into ¾ cup (180 mL) cold to room-temperature water. Set it aside for 5 minutes to hydrate the gelatin.

In a pan over medium-high heat, create a sugar syrup by heating 1 cup (200g) sugar, ½ cup (120 mL) corn syrup, and ¼ cup (60 mL) water. Heat the sugar syrup to 240°F / 115°C and then reduce the heat to low. Whisk in the gelatin and water from the small bowl until it’s completely dissolved in and simmer for a minute or two.

In a large mixing bowl, whisk 4 large (120g) egg whites to soft peak stage, either by hand or with a stand mixer. Slowly drizzle in the hot sugar syrup, whisking the egg whites the entire time. Add 1 teaspoon (5 mL) vanilla extract or other flavoring, and if you like, any food coloring. Continue beating the mixture for a few more minutes to ensure the sugar and gelatin are thoroughly mixed in.

Dust a generous layer of powdered sugar onto the bottom of a baking pan (use a 9” / 20 cm square pan for thicker marshmallows, a larger rectangular one for thinner marshmallows, or a rimmed cookie sheet for mini-marshmallows). Pour the mixture into the pan and then dust more powdered sugar on top. Let the mixture set at room temperature for 8–12 hours. Turn the marshmallow sheet out of the pan onto a cutting board dusted with powdered sugar and cut it into cubes. Coat the sides of the marshmallows with powdered sugar from the cutting board.

Notes

• Try adding vanilla bean scrapings or other flavorings like powdered espresso, peppermint oil, or a shot of liqueur. For color on the outside, try using dyed sugar (see note on page 225); Peeps are coated in yellow granulated sugar, for example.

• If your marshmallows are coming out too sticky or too firm after a full day, try increasing or decreasing the amount of gelatin you’re using. Gelatin comes in different strengths—measured in Blooms, based on a scale created by Oscar Bloom—so there are differences between brands and grades.

Salmon Gravlax

Salt curing has been used for centuries to preserve fish caught at sea. It’s also easy to do at home! Surrounding fish with a sufficient quantity of salt draws out the moisture; this is called dry brining. But salt doesn’t just dry out the food (along with any bacteria and parasites). At sufficient concentration, dry brining actively disrupts a cell’s ability to function and kills it, rendering bacteria and parasites nonviable.

In a bowl, mix together:

On a large piece of plastic wrap, place:

Sprinkle the salt mixture over the fish and massage it in. Wrap the fish in plastic and store it in the fridge, flipping and massaging it twice a day for a day or two.

Store it in the fridge and consume within a week.

Remove the skin by placing the fish skin-side-down on a cutting board and carefully running a knife along the surface between the skin and flesh while using your hand to keep the fish from sliding around.

Notes

• Vodka is used here as a solvent to dissolve some of the non-water-soluble aromatic compounds. You can substitute other spirits, such as cognac or whiskey, to bring additional flavors in. And in place of dill, try using coriander seed, loose tea leaves (e.g., Earl Grey or Lapsang Souchong), shallots, or lemon zest. The Scandinavians traditionally serve salmon gravlax on top of bread with a mustard dill sauce.

• You can substitute other fatty fish, such as tuna, for the salmon and obtain a similar texture.

• This recipe is a bit heavy on the salt—6% by weight—to err on the side of safety. You can reduce the saltiness before eating the fish by rinsing the finished product in fresh water. Curing above 3.5% salt prevents most common bacterial growth, but not all. Modest concentrations of salt prevent Gram-negative bacteria—which are the most common ones found in food—from growing, but won’t handle the few that are Gram-positive, such as Listeria.

• Salt curing—as is done in salmon gravlax—is the first step in making lox. After curing, lox is also cold-smoked, which is the process of exposing a food to smoke vapors that have been cooled down. You can approximate the flavor of lox by adding liquid smoke to the rub—see page 403 for more.

Carolyn Jung’s Preserved Lemons

PHOTO BY JOANNE HOYOUNG-LEE

Carolyn Jung is a food journalist who worked for the San Jose Mercury News as a reporter, food writer, and editor before creating her own blog at http://www.foodgal.com.

What’s a day in the life of a food writer like?

It’s one of the most creative and enjoyable professions there is. Food is this innocuous way to get strangers talking, and it’s a very innocuous way to educate people—and not just about food. It teaches people about culture, about history, about different ethnicities, about different places in the world, about politics, about religion. All of those aspects make it interesting, much more so than people think at the outset.

Where does this recent fascination that people have for cooking come from?

A large impetus has been the Food Network, which has made food such a phenomenon. A lot of people who wouldn’t normally cook were attracted to shows like Iron Chef because it was almost like watching a boxing match or a football game. Who doesn’t dream about being the quarterback on their favorite team? Cooking shows have been the same; you imagine yourself in that contestant’s position. “Oh, my God, if I got a box with mushrooms and lemongrass and chicken and avocado, what the heck would I make?”

What’s been the most unexpected difference between your experience in the print world and your blog?

As a newspaper reporter, I was used to writing very long, involved pieces. On the Web, people don’t have that kind of attention span. You have a shorter window of time to attract a reader online, but you’re also able to build a very loyal audience. If someone likes what you’re doing, they will stay with you.

Are there any particular blog posts that have had much stronger reactions than you expected?

I wrote about how to make preserved lemons, and how I got, as my husband calls it, almost obsessed with watching my lemons. It’s the simplest thing ever. The first time I made this, I would wake up every day and look at my jar of lemons to see what they looked like. It was like a science experiment. The fun part is discovering all the uses there are.

Preserved Lemons

All you need are a half-dozen washed (preferably organic) lemons, salt, and a glass jar with a tight-fitting lid.

Set 1 or 2 lemons aside. Cut the remaining lemons into quarters or eighths and remove any seeds. Sprinkle a thin layer of salt in the bottom of the jar and add a layer of lemons, and then cover them with salt. Continue layering the remaining lemon wedges, covering each layer with salt. Once you’re done, squeeze the juice from the 1 or 2 reserved lemons on top to give the lemons a head start. Store the jar in the fridge. After 2–3 weeks, the lemons will become soft and tender.

Once they’re ready, pick a lemon wedge out of the jar and use it however you’d like—chopped or sliced in thin slivers. The preserved lemon will be quite salty, so hold back any salt that you’d normally use in whatever recipe you’re following, or give the lemon wedge a quick rinse. Preserved lemons are fantastic in tuna salad for sandwiches, or try using them in pastas, bean salads, vinaigrettes, and marinades.

Try adding spices to the salt, or for a less salty, sweeter version, make a mix of 2 parts sugar to 1 part salt.

Bread-and-Butter Quick Pickles

Quick pickles are made from cucumbers sliced into thin discs and cured in hot vinegar mixed with spices and sugar. It’s the sugar that makes them “bread-and-butter” pickles. They’re amazing with their namesake; try them on toasted bread slathered with good butter. Like refrigerator pickles, which are fermented for a few days before refrigeration, these aren’t properly preserved for long-term storage—not that I ever manage to keep them around very long.

In a medium saucepan, measure out:

Wash 1 pound (450g) cucumbers—try to get a pickling variety like Kirby, or use slender, more interesting cucumbers than the standard market variety (“Green Blimp”). Trim and discard both ends and then cut the cucumbers into discs, about 1/8–¼” / 0.5–1 cm thick. Add the slices to the saucepan.

Trim and peel 1–2 onions, about ½ pound (~250g). Slice them in half, root end to tip, and then slice them into thin half-rings. Add the onion slices to the saucepan.

Optionally add more pickling spices or items to pickle—for example, peppercorns, celery seed, a few bay leaves, hot peppers sliced into rings, or a bunch of garlic cloves cut in half.

Bring the ingredients up to a boil and simmer them for 5 minutes with the lid on. Longer simmering times will produce softer pickles. Turn the heat off and allow the pickles to cool until it’s safe to transfer them to a storage container. Store them in the fridge and use them within a few weeks.

Notes

• Sea salt doesn’t have any iodine or anticaking additives, which cloud up water. It’s also half as dense as table salt, so if you substitute table salt for sea salt, adjust the volume measurements accordingly. Try mixing 2 tablespoons (20g) of sea salt into one glass of water and 1 tablespoon (18g) of table salt into a second glass to see the difference in how clear they are.

• When I first thought of using pickles as an example of preservation, I thought it’d be easy to explain. Heat, salinity, and acidity all kill pathogens! Turns out, that’s not enough. These quick pickles aren’t properly preserved, contrary to what many cookbooks and food shows say. Using hot vinegar speeds up how quickly the pickles are ready to eat, but the heat and pH change isn’t enough to handle C. botulinum. Without a true canning step, these pickles aren’t safe for long-term storage, even in the fridge, as the spores from C. botulinum are extremely hardy. Treat quick pickles like any other perishable food: keep them refrigerated and eat them within a few weeks.

• If you want to make shelf-stable pickles, you’ll need to can them. Canning is a good example of multiple preservation techniques being combined: cooking sealed jars in hot water removes Listeria, and the vinegar drops the pH to a range that C. botulinum spores won’t germinate in. The pH is critical: it must be below 4.6 because the canning step alone won’t destroy bacterial spores. Even changing the ratio of liquid to solids when making pickles can shift the pH! For canning steps for bread-and-butter pickles, see http://cookingforgeeks.com/book/pickles/. Tip: you don’t need a boiling water canner; use a large pot for boiling the water and a trivet you don’t mind getting wet set into the bottom of the pot.

Hervé This on Molecular Gastronomy

PHOTOS USED BY PERMISSION OF HERVÉ THIS

Hervé This (pronounced “teess”) is a researcher at L’Institut National de la Recherche Agronomique in Paris known for his studies of chemical changes that occur in the process of cooking. Along with Nicholas Kurti and others, he organized the first “International Workshop on Molecular and Physical Gastronomy,” held in 1992 at Erice in Sicily, Italy.

What was the original reason you and Dr. Kurti had for picking the name “molecular and physical gastronomy”?

Nicholas Kurti was a retired professor of physics. He loved cooking, and he wanted to apply new technology in the kitchen—ideas from the physical lab, mostly vacuum and cold, low temperatures. For myself, the idea was different: I wanted to collect and test the old wives’ tales of cooking. Also, I wanted to use some tools in the kitchen that were already in chemistry labs.

For many years, when I was doing an experiment in Paris, he was repeating it in Oxford, and what he was doing in Oxford, I was repeating in Paris. It was great fun. In 1988, I proposed to Nicholas to create an international association of the kind of thing that we were doing. Nicholas said to me that it was too early but, probably, it would be a good idea to make a workshop with friends meeting together. This is why we needed a name, so I proposed “molecular gastronomy,” and at that time, Nicholas, who was a physicist, had the feeling that that would put too much emphasis on chemistry, so he proposed “molecular and physical gastronomy.” I accepted the idea only because Nicholas was a great friend of mine, not because I was convinced scientifically.

In the beginning, I published a paper in a main journal in organic chemistry, and in this paper I made the confusion between technology and science. In 1999, I realized that a clear distinction should be made between engineering and science because it is different.

How does the work that you do with molecular gastronomy differ from what a food scientist does who publishes in journals such as theJournal of Food Science?

It is a question of history. At that time [1988], food science was more the science of food ingredients or food technology. You had papers on, let’s say, the chemical composition of carrots. Nicholas and I were not interested at all in the chemical composition of carrots, in the chemistry of ingredients.

We wanted to do science, to explore the phenomena that you observe when you cook, and cooking was completely forgotten at that time. In the previous centuries, Lavoisier and others studied how to cook meat broth. This was exactly what we are doing. Food science had drifted; cooking was completely forgotten. Recently, I took the 1988 edition of Food Chemistry by Belitz and Grosch—a very important book in food science—and looked at the chapters on meat and wine. There is almost nothing about cooking wine or cooking meat; it is very strange.

It seems like there is much confusion about what you mean with the term “molecular gastronomy.”

Molecular gastronomy means looking for the mechanism of phenomena that you observe during cooking processes. Food science in general is not exactly that. If you look at the table of contents of the Journal of Agricultural and Food Chemistry, you will see very little material referring to molecular gastronomy.

So, molecular gastronomy is a subset of food science that deals specifically with transformation of food?

Exactly, it is a subset. In 2002, I introduced a new formalism in order to describe the physical organization of colloidal matter and of the dishes. This formalism can apply to food and also to any formulated products: drugs, coatings, paintings, dyes, cosmetics. It has something to do with physical chemistry and, of course, it has something to do with molecular gastronomy. So it’s true that molecular gastronomy is a particular kind of food science, but also it’s a particular kind of a physical chemistry.

It’s fascinating to see how easy it is to make inventions or applications from science. Every month I give an invention to Pierre Gagnaire. I should not, because it is invention, not discovery, but I can tell you that I just have to snap the finger and the invention is there. I take one idea of science, I ask myself, “What can I do with that?” and then I find a new application. It is very, very easy. The relationship is of use, and this is probably the reason why there is so much confusion between science and technology. We’ve been studying carrot stocks. We were studying what is going out of carrot roots into the water and how is it going out. One day, I came to the lab. I was looking at two carrot stocks made from the same carrot. One stock was brown; the other was orange. It was the same carrot, same water, same temperature, same time of cooking, and one stock was brown; the other was orange. I stopped everybody in the lab saying, “We have to focus on this, because we don’t understand anything.”

We focused on this story, and it was due to the fact that one preparation was made in front of light, and the other was in the darkness, and, indeed, we discovered that if you shine some light on the carrot stock, it will turn brown. So we explored the mechanism, how it turned brown. It was a discovery, not an invention, and thus it was science. At the same time, the application is of use, because cooks want to get a beautiful golden color to stocks, and in order to get the brown color, they grill onions and they put them in the stock. I can tell cooks now: avoid the onions and just add some light. So you see, the discovery is leading to invention immediately.

Tell me more about your collaboration with Chef Pierre Gagnaire.

I don’t know if it is a collaboration, it’s a friendship. Pierre’s wife told Pierre more than 10 years ago, “You’re crazy and Hervé is crazy, so you probably could play together.”

The real story is that, in 1998, Pierre opened a new restaurant in Paris. He was launching the restaurant with lunches for the press, for the media, for politics, etc., and I was invited. I did not know him, except from reputation, at the time. One year passed, and I was asked by the newspaper Libération for recipes for Christmas—scientific recipes. I told them I’m not a chef, and that I should not give recipes. I proposed, instead, that I would invite two wonderful chefs to do recipes from ideas that I would give to them, and Pierre Gagnaire would be one of the two chefs.

When I was in the cab driving to the restaurant for the interview and the picture, I realized that beer can make a foam. It means that you have proteins that are surfactants that can wrap the air bubbles. If the proteins can wrap the air bubbles, it means that they can wrap oil. When I arrived in the restaurant, Pierre was there; immediately I asked him, “Do you have some beer, and some oil, one whisk and one bowl?” He looked at me, and he asked for the ingredients and the hardware, and I told him, “Please, put some beer and then whisk the oil into the beer; I can predict that you will get an emulsion.” And he got it. He tasted the emulsion, and he found it very interesting, and he decided to make the dish after this wonderful emulsion.

One year later I was invited to lecture at the Academy of Sciences. I proposed to them to make the lecture with a dinner from Pierre. We worked for three months, meeting every Monday morning between 7 and 10. It was so fun that we decided that we had to play on and we never stopped. It’s not collaboration, it’s just playing together, where we are children.

It seems like some of the more novel cuisines are removed from the normal dining experience. How much of that experience is created by taking scientific discoveries and applying them to a meal, as opposed to a chef having a concept and coming to a scientist and asking, “Is there a way to make this?”

Well, there are many questions in that one. I have the feeling that we don’t cook the way we should. For example, we are still roasting chicken. Is it a good idea? I don’t know. We ask the question, “Should we go on as we always have?” Many chefs are changing their ways. Many of my inventions are free on Pierre Gagnaire’s website, and I know that chefs go there to get ideas for the kitchen. I publish the ideas for free; there are no patents, there is no money involved. It is all for free because I want to rationalize the way we cook. We don’t cook in a rational way. We are still roasting chicken.

For one of the books that I published, the title was translated as Cooking: The Quintessential Art, but in French it was Cooking: Love, Art, and Technique. The idea that cooking is an art was not even admitted some years ago: “Real art is painting or music or sculpture or literature.” I remember talking with a minister of public education in France. He was saying, “No, no, no, it’s not art. You’re just joking; it’s cooking.” It’s love first, then art, then technique. Of course, technology can be useful only for the technical part, not for the art, and not for the love component. Nowadays, Ferran of elBulli and Alinea’s Grant Achatz are using the technique, but there are a lot of possibilities for improvement. They will make their own interpretation, and then science has nothing to do with that. It is personal interpretation; it is feeling.

Do you think that elBulli and Alinea, or restaurants like them, are able to sufficiently use all three components: love, art, and technique?

The love component of cooking is not really formalized. The science needed is still not there. I have the idea that we need to do some science on the love component. Because I’m a physical chemist, it’s not very easy for me to make this study. It’s still very primitive. Currently, the chef behaves intuitively with the love component. If someone is friendly, he will greet you at the entrance of the restaurant, “Ah, here you are, very happy to have you,” and you are happy because you’re greeted as kind of a friend. But this is intuition. What I’m saying is that we need to scientifically study the mechanism of phenomena of this friendship. We don’t have this mechanism currently.

It almost sounds like psychology or sociology.

It is, exactly. My way of doing molecular gastronomy is to do physical chemistry, daily, at the lab, but I’m producing the concepts so that other people can pursue them in their own way. Their own way can be psychology, sociology, history, geography; we need the knowledge to understand the mechanism of phenomena that we observe in cooking. It is a very foolish idea to think that we cannot investigate all the phenomena. It can be done. Imagine that I discover, or someone discovers, a way to give more love to a dish. It means that the guest will be happier. But imagine that you give this knowledge to a dishonest guy, then the guy would use the knowledge dishonestly, and this will increase the power of dishonest people. If you give the same knowledge to kind people, they will do their best. This is the same question as with nuclear physics. If you are acting poorly, you will make a bomb; if you try to act for the good of humankind, you will make electricity. Science is not responsible for the application; you are responsible for the application.

Citrus Marmalade

Making marmalade involves boiling sliced citrus fruits in sugar water. The combination of pectin from the citrus rind and acid from the fruit’s flesh makes this one of the easiest types of jellies to make. Add sugar and water, and after heating, the naturally present pectin will form a gel. For an intensely bitter and traditional marmalade, use Seville oranges, which are extremely high in pectin. For a deep red color, try mixing in blood oranges.

Prepare 1 pound (450g) citrus fruits such as lemons, oranges, grapefruit, or limes (or use a mix of all four—it’s amazing!) by giving the skins a good scrub under water to remove any residues. Slice the top and bottom off each fruit, cut it into quarters, and then cut out the seeds and center core. Slice the fruit into very thin strips and transfer it to a saucepan.

Add 1½ cups (300g) sugar and enough water to cover the fruit and sugar. Bring the mixture to a boil and then simmer, with the lid on, for half an hour or so, until the rinds are soft. Once the fruit has softened, remove it from the heat. If the marmalade is too bitter for you at this point, add more sugar.

Cool the marmalade and store it in the fridge.

Notes

• If you’ve made this before, try using some citrus juice or honey in place of some of the water. If you like, add spices such as whole cloves, a cinnamon stick, or a vanilla bean to the mix before boiling it.

• Besides slathering it on toast, try using a spoonful of the marmalade in steel-cut oatmeal, on pancakes, whisked into yogurt, as part of an appetizer cheese plate, in baked goods, or mixed in with whipped cream on top of cake. Marmalades can also be great as glazes on pork chops or duck, mixed in with roasted root vegetables, and even tossed in a vinaigrette for salad dressings.

Candied Orange Rind

Candied rind is great chopped up and added to cookies, on top of desserts, or simply dipped into tempered chocolate (see page 157). Boiling the rind softens the tissue and neutralizes one of the bitter compounds in citrus pith, limonin. Sugar acts as a preservative by binding with water, but it’s not foolproof. Mold needs less available water than bacteria to grow, so if your rinds are too moist, you may see mold growth (and not the delicious kind).

In a pot, bring to a boil:

Simmer for 20–30 minutes, until the rinds are tender. Remove the rinds from the pot and dry them on paper towels. Store the rinds in a container with sugar surrounding them to further dry them out.

Note

• Try other citrus fruits, such as grapefruits, lemons, limes, or tangerines, or fruits such as cherries, peaches, or apples. You can add spices such as cinnamon to the water as well, or substitute dark rum or a liqueur such as Grand Marnier for part of the water.

Vanilla Extract

Vanilla extract is a classic example of using alcohol as a solvent. Very few plant-based compounds are soluble in water—they’d wash away in nature. Hot water will work in some cases—how else would mint or chamomile tea work?—but when making extracts, you’ll need to use either ethanol or fat, depending upon the molecule you’re trying to extract. (Most aromas are based on multiple compounds, a detail I’m skipping here.)

Vanilla extract is easy to make. Ethanol from a spirit such as vodka (80 proof will be about 40% ethanol) will dissolve some of the 200+ compounds in the vanilla bean responsible for vanilla aroma, including vanillin, which gives vanilla most of its hallmark flavor. (The different ratios of some of the more pronounced compounds are what cause differences between various cultivars of vanilla.)

Vanilla beans are still pricey. Buy them online, and for making vanilla extract, Grade B is just fine. (Grade B is what industry normally uses—who cares that the pods aren’t as pretty when they’re going to be chopped up?)

In a small glass jar with a tight-fitting lid, put:

Screw the lid on the jar or place plastic wrap over the jar’s top and store it in a cool, dark place (e.g., a pantry). Give the extract at least several weeks to steep.

Notes

• The vanilla bean can be left over from some other recipe. If you cook with vanilla frequently, consider keeping the jar of vanilla constantly topped off. Whenever you use a vanilla bean, add it to the jar, removing an old one when space requires it. And as you use the extract, occasionally top off the jar with a bit more liquid.

• Play with other variations: instead of vodka, which is used for its high ethanol content and general lack of flavor, you can use other spirits such as rum, brandy, or a blend of these. Or, instead of vanilla beans, try using star anise, cloves, or cinnamon sticks. Try varying both solvent and solute (e.g., Grand Marnier with orange peel in it).

Infused Oils and Herbed Butters

Infused oils and herbed butters, like extracts used in cooking, can carry flavor from plants into your food. Unlike extracts, which have a harsh taste from the alcohol, infusions can be used as part of the finished dish. Salad dressed with a basil-infused oil? Salmon drizzled with rosemary-infused oil? Basil butter on bread? Next time you have extra herbs, try mixing them in with a fat.

Fats and oils are nonpolar molecules (see page 398), so given the chemistry rule of thumb that like dissolves like, it’s no surprise that they dissolve other polar molecules. Many odor compounds are bound up in plant oils—oregano has carvacrol in oil droplets on the leaf surface—but not all plant odor compounds are fat-soluble. I tried making sage-infused oil with only mild success; a search online showed that one of the primary odorants of sage, manool, is normally dissolved with alcohol. A quick test making an ethanol-based sage extract worked instantly, giving recognizable sage flavor. If you find an herb doesn’t infuse well, use it for herbed butter. Unlike infused oils that have the plant matter strained out, herbed butters don’t rely on the fat solubility of the odorants.

Infused Oils

You can infuse oils using either a cold process or heat process. Cold processing is better for herbs; spices do better in heated oils, which will bloom them, changing their flavor.

1. In a small bowl, measure out about 1 cup (240 mL) of a high-quality, neutral oil such as grapeseed, sunflower, or canola oil; for stronger-flavored herbs, a mild olive oil works well.

2. Infuse!

3. For herb infusions, follow a cold process: Add 2–4 tablespoons (10–20g) herbs such as rosemary, oregano, or basil, finely diced. Optionally add 1–2 tablespoons (5–10g) parsley to make the infused oil greener. Using either a traditional blender or an immersion blender, blend the oil and herbs for 30 seconds or so. This will speed up the rest period; otherwise, you’ll need to let the mixture rest in the fridge for much longer.

4. For spice infusions, follow a heat process: Add spices to the oil; try using a single spice, like cardamom or cinnamon, or a mix. For a simple curry oil, use 2 tablespoons (12g) curry powder, 1 tablespoon (6g) fresh ginger (finely minced), and ½ teaspoon (1g) cayenne pepper or chili flakes. Add the oil to a pan over medium heat and heat the mixture for a few minutes to bloom the spices. (You should be able to smell them!)

5. Transfer the infused oil back into the small bowl and cover. Cold-processed oils should rest for a few hours or overnight in the fridge. Heat-based infusions can be used right away, but allow them to rest a few minutes to cool to room temperature.

6. For clearer infusions with fresh herbs, filter the mixture though a fine mesh strainer or a strainer lined with cheesecloth (after it’s rested!). To avoid cloudiness, don’t press down on the mixture; allow it to drip separate for a few minutes.

Herbed Butters

Herbed butters are easier than infused oils: they don’t rely on the flavor compound dissolving because the plant matter itself remains as part of the final product. Use flavorful herbs; more tender herbs like chives, tarragon, and sage are fast and easy to work with.

In a small mixing bowl, let ½ cup (115g) butter come up to room temperature. If your butter is unsalted, add ½ teaspoon (3g) salt; optionally add freshly ground pepper. Add about 2–3 tablespoons (10–15g) herb leaves, washed and diced, and with any stems removed (you don’t want little twiggy things in your butter!). Using a fork, mash the herbs and any seasoning into the butter. Serve it with bread or use it as an ingredient—try spreading a thin layer on top of cooked fish or meats.

Notes

• Infusing a food’s odor compounds into oil or vinegar doesn’t change the properties of the compound. If it’s heat-sensitive in the ingredient, it’s going to be heat-sensitive in the infused version. Pan-searing pork with sage butter works fine, but a basil-infused oil would suffer.

• Store fresh-herb-infused oils and herbed butters in the fridge and use them within a week. Oils and fats with non-acidic wet plant matter immersed in them create a perfect anaerobic breeding ground for botulism. While uncommon, it is fatal if given time to fester. If you want to make shelf-stable infused oils with “wet” ingredients, you will either need to properly pressure-can the jars or acidify the plant matter—see http://cookingforgeeks.com/book/infusedoils/ for details. Dried spices and dried herbs don’t have enough moisture to support rapid microbial growth, so infusions like dried peppers in oil that are heat-processed can be used for up to 3 months, although the US FDA recommendations are to keep them refrigerated and use them within 3 weeks.

S’mores Ice Cream

S’mores ice cream? You can’t roast ice cream, but with liquid smoke, you can add in the smoky flavor. You’ll need a standard ice cream mixer, or you can go all-out geek and either make your own (see the lab on making ice cream with salt and ice on page 394) or use liquid nitrogen (see page 363).

This recipe uses liquid smoke to impart the toasted flavor of campfire-roasted marshmallows (make your own—see page 381). The concept was inspired by a demo by Kent Kirshenbaum of NYU’s Experimental Cuisine Collective.

To create the base, combine in a mixing bowl:

Proceed with the directions for your chosen method of making ice cream. Once the ice cream has set, stir in:

Serve the ice cream with hot fudge or chocolate syrup—whipped cream, cherries, and nuts optional.

Note

• Try freezing the graham crackers after toasting and chopping them up but before adding them to the base. This will yield crunchier graham cracker bits, as they won’t absorb as much moisture when frozen. This trick works for most dry goods that would normally get soggy when added to the ice cream base.

Oven-Cooked Barbecue Ribs

In a large baking pan (9” × 13” / 23 cm × 33 cm), place:

2 pounds (900g) pork baby back ribs, excess fat trimmed off

In a small bowl, create a dry rub by mixing:

Cover the ribs with the spice mix. Cover the baking pan with foil and bake at 300°F / 150°C for 2 hours.

In a small bowl, create a sauce by mixing:

Remove the foil from the baking pan and coat the ribs with the sauce. Bake for 45 minutes, or until done.

Note

• Experiment with other savory spices in the dry rub, such as chilies, garlic, or paprika. Also, try adding items such as onions, garlic, or Tabasco to the sauce.

Lemon Meringue Pie

Lemon meringue pie is the combination of three separate components, each with its own chemistry and challenges: pie dough, a meringue, and a custard-like filling. We’ve already covered pie dough (see page 259) and meringues (see page 293), so the only thing left is the filling itself. Flip to those recipes for instructions on how to make the pie dough and meringue topping, and blind-bake the bottom shell.

To make the lemon custard, place in a saucepan off heat and whisk together:

Add 3 cups (720 mL) of water, whisk the ingredients together, and place the saucepan over medium heat. Stir the mixture until boiling and the cornstarch has set. Remove the pan from the heat.

In a separate bowl, whisk together:

Save the whites for making the meringue. Make sure not to get any egg yolk in the whites! The fats in the yolk (nonpolar) will prevent the whites from being able to form a foam when whisked.

Slowly add about a quarter of the cornstarch mixture to the egg yolks while whisking continuously. This will mix the yolks into the cornstarch mixture without cooking the egg yolks (tempering). Transfer the entire egg mixture back into the saucepan, whisk in the following ingredients, and return the pan to medium heat and cook the mixture until the eggs are set, about a minute:

Transfer the filling to a prebaked pie shell. Cover the shell with Italian meringue made using the 6 egg whites (see page 293, making a double batch), and bake the pie in a preheated oven at 375°F / 190°C for 10–15 minutes, until the meringue begins to turn brown on top. Remove the pie and let it cool for at least 4 hours—unless you want to serve it in soup bowls with spoons—so that the cornstarch has time to gel.

To create decorative peaks on the meringue, use the back of a spoon: touch the surface of the unbaked meringue and pull upward. The meringue will stick to the back of the spoon and form peaks.

Ann Barrett on Texture

PHOTO USED BY PERMISSION OF ANN BARRETT

Ann Barrett is a food engineer specializing in food textures. She works for the Combat Feeding Directorate of the US Army Natick Soldier Research, Development, and Engineering Center (NSRDEC).

What does a food engineer do?

It’s like applied chemical engineering but for food. The training focuses on how to process food and how to preserve food, looking at food as material. I happen to have a specialty in food texture or food rheology; rheology means how something flows or deforms. My PhD topic was on the fracturability of crunchy food. How do you measure crunchiness or fracturability, and how do you quantitatively describe the way a food fails? When you chew a food and it breaks apart, can you describe that quantitatively and then relate that to the physical structure of the food?

Tell me a little bit about the NSRDEC.

There are several RDECs (research, development, and engineering centers) throughout the country. NSRDEC is focused on everything the soldier needs for survival or sustenance, aside from weaponry: food, clothing, shelters, and parachutes. The food part is largely driven by the fact that the military is potentially deployed in every kind of physical environment, so we need a wide range of foods to support soldiers operating in a wide range of situations. They have large depots of rations, and that drives a very long shelf-life requirement. Most of the food that we make needs to be shelf-stable for three years at 80°F / 26.7°C. That is not to say that the soldier will always eat something that’s three years old, but they definitely might. That drives a lot of the research here; foods that are shelf-stable but also good, that the soldiers will want to eat.

It must be really interesting to work with the constraints that you’ve got while trying to preserve flavor and texture. How do you go about doing that?

Well, it’s often one part experience or knowledge combined with two parts trial and error. There’s a lot of bench-top development here. Most of my experience has been in processing and engineering analysis of food, but I do have a project now where we’re trying to develop flavors for sandwich fillings. All flavors are chemicals, so you can replicate a natural flavor by knowing what the chemistry is.

For example, we’re working on a peanut butter filling for sandwiches. We’re trying to make a chocolate peanut butter flavor, a bit like Nutella. We have the peanut butter formula, and we’ve been looking at adding cocoa and at different chocolate flavors. We put three into storage to see how they would work, and two of them came out just okay, and one of them was delicious. When you’re developing something, you have to look at a number of different ingredients to see what works. There will be changes in both the flavor and texture of a food during long-term storage. Flavors tend to become less intense, or off-flavors might develop. Texture can degrade by moisture equilibrating, say in a sandwich, or by staling. There are a multitude of flavors that are commercially available, and also a multitude of ingredients that will adjust texture—for example, starches and gums for liquid or semisolid foods, enzymes and dough conditioners for breads. So during development you need to optimize a formula to make sure the food is good after you make it and also good after storage.

Even with all the hard science, you still have some degree of, well, “Let’s just try it and see what happens?”

Oh, absolutely. You make a product up for a project, sample it, store it, and then sample it again. Everything is actually tasted here, and as a matter of fact, part of our duties is to go over and participate in the sensory panels because the food scientists here, the nutritionists, the dieticians, are all considered expert tasters. The first thing we do is make our product on the bench and then put it into a box that’s 120°F / 49°C for four weeks. Those conditions approximate a longer period of time at a lower temperature; it’s just a quick test to see if quality holds up. If the product holds up, next is 100°F / 38°C for six months; that’s supposed to approximate the quality you would get at three years at 80°F / 27°C. Then you have to check that it’s microbiologically stable, so it goes to the microbiologist for clearance, and then you can ask people to come and evaluate it. We rate the appearance, aroma, flavor, texture, and the overall quality.

How does the science of food texture work into enjoyment of food?

There are expected textural properties of whatever food category you’re dealing with. Sauces are supposed to be creamy; meats are supposed to be at least somewhat fibrous; bread and cake are supposed to be soft and spongy; cereals and crackers are supposed to be crunchy. When texture deviates from what’s expected, the food quality is poor. If you are going to measure and to optimize the texture of a product, you need to pinpoint the exact sensory properties you want.

For example, for liquids, flowability or viscosity is the defining physical and measurable characteristic. There are “thin” liquids and “thick” liquids, and you can often change thin to thick by adding hydrocolloids or thermal treatment. Solid foods come in many different textural types. There are elastic solids that spring back after deformation (Jell-O); there are plastic solids that don’t (peanut butter). Then besides “solid” solids there are also porous solids—think bread, cake, puffed cereal, extruded snacks such as cheese puffs. Porous foods have the structure of sponges, and like a wet versus a dry sponge, they can be elastic or brittle.

Somebody cooking in the kitchen is actually manipulating these things both physically and chemically?

Yes, that’s exactly what cooking is. Take cooking an egg. The protein albumin will denature with heat, causing molecular crosslinking and solidification. Another example is kneading bread dough, which is a mechanical rather than a thermal process that makes the gluten molecules link up; that gluten network is what allows the bread to rise because a structure is developed that will hold gas liberated by yeast. And of course, every time you use cornstarch or flour to thicken a gravy or sauce, you’re employing a physico-chemical process. Heat and moisture will make the starch granules absorb water and swell and then bleed out individual starch polymers, which are like threads attached to the granules. The starch polymers then entangle, creating an interconnected structure that builds viscosity. That’s why your gravy gets thick.

Hot Marshmallows

Unlike the marshmallows covered earlier in this chapter (see page 383), these marshmallows firm up when heated but melt when they cool. This recipe is adapted from a recipe by Linda Anctil (http://www.playingwithfireandwater.com); see page 121 for more about Linda.

In a saucepan, bring to a boil:

Let cool, and then whisk in:

Let the mixture rest in the fridge until thick, around 2 hours. Once it’s thick, whisk it for 2–3 minutes to create a super-frothy foam. Transfer to a 9” × 9” / 20 cm × 20 cm baking pan lined with parchment paper. Bake it for 5–8 minutes at 325°F / 160°C, until set. The marshmallows should feel dry to the touch and not at all sticky. Remove the pan from the oven, cut the marshmallows into your desired shapes, and coat them with powdered sugar.

Two marshmallows on a plate of powdered sugar.

Two marshmallows after being coated with powdered sugar while still hot.

Same marshmallows after cooling for a few minutes.

When working with gels, you can quickly cool the hot liquid by whisking it while running cold water over the outside of the pan. The water will adhere to the bottom of the pan.

Powdered Brown Butter

Browned butter tastes rich and nutty, and is great for adding flavor (see page 156). When melted and whisked with maltodextrin, it can be turned into a powder that “melts” back into browned butter in your mouth. Try using this browned butter powder as a garnish on top of or alongside fish, or making a version with peanut butter and sprinkling it on desserts.

In a skillet, melt:

Once the butter is melted, continue to heat it until all the water has boiled off. The butter solids will start to brown. Once the butter has completely browned and achieved a nutty, toasted aroma, remove it from the heat and allow it to cool for a minute or two.

In a small mixing bowl, measure out:

While whisking the maltodextrin, slowly dribble in the browned butter until the mixture reaches the consistency of wet sand.

Notes

• Stir slowly at the beginning because maltodextrin is light and will easily aerosolize. The ratio between maltodextrin and the food will vary. If your result is more like toothpaste, add more maltodextrin.

• If the resulting powder is still too clumpy, try drying it carefully by transferring it to a frying pan and applying low heat for a few minutes. This will help eliminate any dampness present from room humidity. It will also partially cook the food item, which might not work for powders containing ingredients such as white chocolate.

• For a finer texture, try passing the powder through a sieve or strainer using the back of a spoon.

• Additional flavors to try: peanut butter, almond butter, coconut oil (virgin/unrefined), caramel, white chocolate, Nutella, olive oil, bacon fat (cook some bacon and save the fat drippings—this is called rendering). You don’t need to heat the fats first, but it might take a bit of working to get the maltodextrin to combine. For liquid fats (e.g., olive oil), you will need to use roughly 2 parts maltodextrin to 1 part fat: 50g olive oil, 100g maltodextrin.

Gelled Milk with Iota and Kappa Carrageenan

This isn’t, in and of itself, a tasty recipe (add some chocolate, though, and you’ve got the beginnings of commercial chocolate pudding). Still, it will give you a good sense of what adding a gelling agent does to a liquid and provides a good comparison between flexible and brittle gels.

Flexible brittle version

In a saucepan, whisk to combine and then bring to a boil:

Pour the mixture into a glass, ice cube tray, or mold and chill it in the fridge until set (about 10 minutes).

Firm brittle version

Again in a saucepan, whisk to combine and then bring to a boil:

Pour the mixture into a second glass, ice cube tray, or mold and chill it in the fridge until set.

Notes

• Try modifying the recipe by adding 1 teaspoon (4g) of sugar and substituting half-and-half for the milk. Microwave the mixture for a minute to set it and then pour the hot liquid into a ramekin that has a thin layer of jam or jelly and toasted sliced almonds in the bottom. Once it’s gelled, invert the set gel onto a plate for something roughly approximating a flan-style custard.

• Since the carrageenan is thermoreversible (once gelled, it can still be melted), you can take a block of food gelled with kappa carrageenan, slice it into cubes, and do silly things like serve it with coffee or tea (one lump or two?).

• You can take a firm brittle gel and break up the structure using a whisk to create dishes like thick chocolate pudding.

Chocolate Panna Cotta

Panna cotta—Italian for “cooked cream”—traditionally gets its structure from gelatin, but a small amount of agar can create a more stable version, and one that happens to be vegetarian. This is a good example of how agar can be used to provide a firmer texture than traditional ingredients, useful for applications that require additional strength.

In a saucepan, whisk together and gently simmer (below boiling—just until small bubbles form on the surface) for 1 minute:

Turn off heat, remove the vanilla bean pod, and add, briefly stir, and let rest:

After a minute, add and whisk to thoroughly combine:

Pour the mixture into glasses, a bowl, or molds and store it in the fridge. The gel will set in as little as 15 minutes, depending upon the size of the mold and how long it takes the mousse to drop below agar’s gelling point (around 90°F / 32°C).

Note

• Try using this recipe as a component for other desserts. Roll a ball in toasted nuts to create a truffle-like confection, or spread a layer of it before it sets into a prebaked pie crust and then top it with raspberries and whipped cream.

Clarified Lime Juice

We talked about using gels to clarify liquids in the previous chapter (see page 349), but what if the liquid you’re using doesn’t naturally gel? Adding agar to a liquid will set it up into something that allows for gel clarification. This example, for clear lime juice, comes from Dave Arnold (see page 358).

Squeeze the juice from 10 limes into a container, running it through a sieve to remove the pulp. Measure the juice; it should be around 2 cups (480 mL). Set it aside.

In a pan, create an agar gel using water and agar by mixing ½ cup water (120 mL) with 7 teaspoons (14g) agar, heating the liquid to a boil to melt the agar. (This will create an agar gel at about 10% agar; when mixed with the lime juice it’ll result in a roughly 2.0% concentration.)

Once the agar has melted, remove the pan from the heat and pour the water–agar mixture into the container with the lime juice. Let it rest for a half hour or so, until set.

Once the lime gel has set, use a whisk to break it into pieces. Make zigzag slashing cuts with the whisk; don’t actually whisk the gel.

Transfer the broken gel to a cheesecloth (real cheesecloth, not the loose mesh stuff) or towel. Fold the cloth up into a ball.

Hold the balled cloth above a coffee filter and squeeze it with your other hand, massaging it to force out as much liquid as possible. (The coffee filter will catch any small chunks of agar that happen to leak through.) Remove the filter and use the juice as desired.

Martin Lersch’s Hydrocolloid Recipes

PHOTO USED BY PERMISSION OF MARTIN LERSCH

Martin Lersch is a chemist who writes about food at http://khymos.org and is the editor of Texture: A Hydrocolloid Recipe Collection (http://blog.khymos.org/recipe-collection/).

How did you get interested in chemistry in cooking?

My whole food interest is in no way related to my studies or my work, apart from chemistry. I’ve always liked cooking. Every chemist should actually be a decent cook, because chemists, at least organic chemists, are very used to following recipes. It’s what they do every day at the lab. I often tease my colleagues, especially if they claim that they can’t bring a cake to the office for a meeting; I say, “Well, as a chemist, you should be able to follow a recipe!” I’ve always had, in a way, curiosity. I bring that curiosity back home into the kitchen and wonder, “Why does the recipe tell me to do this or that?” That’s really the case.

How has your science background impacted the way that you think about cooking?

I think about cooking from a chemical perspective. What you do in cooking is actually a lot of chemical and physical changes. Perhaps the most important thing is temperature, because many changes in the kitchen are due to temperature variations. Searing meat and sous vide are also good places to start. With sous vide, people gradually arrive at the whole concept themselves. If you ask them how they would prepare a good steak, many people would say you should take it out of the refrigerator ahead of time, so you temper the meat. While you temper it, why not just put it in the sink? You could use lukewarm water. Then if you take that further, why not actually temper the meat at the desired core temperature? Most people will say that’s a good idea, then I say that’s sous vide. It becomes obvious for people that that’s actually a good idea.

I’m very fascinated by the hydrocolloids. One of the reasons I spent so much time putting the recipes together was that when I bought hydrocolloids, maybe one or two recipes would be included, but I found them not to be very illustrative. Everyone is familiar with gelatin, less so with pectin, but all the rest are largely unfamiliar. People don’t know how they work, how you should disperse them and hydrate them, or their properties. The idea was to collect recipes that illustrate as many of the ways to use them as possible. You can read a couple of the recipes and then can go into the kitchen and do your own stuff. That’s what I hope it will enable people to do.

Is there a particular recipe from which you’ve learned the most or found interesting or unexpected in some way?

It’s hard to think of one recipe. When talking about molecular gastronomy, it’s easy to focus too much on the fancy applications like using liquid nitrogen or hydrocolloids. It’s important to emphasize that this is not what molecular gastronomy is about, although many people think that; many people associate molecular gastronomy with foams and alginate.

For a great collection of several hundred recipes based on gelling agents, check out Texture: A Hydrocolloid Recipe Collection, available online for free on Martin’s blog at http://blog.khymos.org/recipe-collection/ (mirrored at http://cookingforgeeks.com/book/hydrocolloid/).

Mayonnaise

You needn’t buy lecithin powder to experience the magic of lecithin. Egg yolks are used to make mayonnaise because of their high lecithin content. Use a fresh egg for this; lecithin in egg yolks breaks down over time. (Lots of things in eggs break down over time! See page 187 for more on eggs.) If you want to avoid the raw egg, see the note about vegan mayonnaise. Homemade mayo is especially worth it when used as a dipping sauce or directly on top of salmon.

In a large mixing bowl, separate out 1 large (20g) egg yolk, saving the white for something else. Add 4 teaspoons (20 mL) lemon juice or light-colored vinegar (white wine vinegar or Champagne vinegar) or a mix of the two, 1 teaspoon (6g) mustard, and ½ teaspoon (3g) salt and whisk the ingredients together to combine.

Slowly drizzle in 1 cup (240 mL) oil (such as olive oil) while whisking. (For more flavor, try using an infused oil; see page 401.) If you add the oil too quickly or don’t whisk enough, the emulsion will separate back out; this is called breaking. If that happens and you can’t whisk it back together, add an egg yolk to a clean bowl and slowly whisk in the broken sauce.

Add salt and pepper to taste. Store the mayo in the fridge and use it within a week or so.

Note

• If you have lecithin powder that’s derived from soya, try making a vegan mayonnaise. Replace the egg yolk with 2 teaspoons (10 mL) water, 1 teaspoon (5 mL) oil, and ½ teaspoon (1.5g) lecithin powder.

Fruit Juice Foam

Foams are a fun, interesting component to a dish. We use whipped cream on top of many desserts, but what if we could come up with a foamed topping for savory applications? Try this with any strongly flavored liquid, such as coffee, or a brightly colored liquid like beet juice. Lecithin foams best at around a 1–2% concentration (2g lecithin per 100 mL of liquid).

In a large mixing bowl or other similarly large and flat container, measure out:

If you have an immersion blender, blend the ingredients together for a minute or so, angling the blade so that it’s whisking air in. If you don’t have an immersion blender, use either a hand mixer or a whisk, being a little more patient.

Allow the mixture to rest for a minute after blending, so that the resulting foam that you spoon off is more stable.

Foamed carrot juice made with lecithin is surprisingly stable for long periods of time.

Mozzarella Cheese

Making your own cheese is a great experiment to see how closely related two seemingly different things can be. Cheese is made from curds—coagulated casein proteins—in milk. The whey is separated out via an enzymatic reaction, allowing the curds to be cooked and then kneaded, stretched, and folded to create that characteristic structure found in string cheese.

In two small bowls or glasses, measure out and set aside:

In a stock pot, mix and slowly heat to 88°F / 31°C:

Once the liquid is at 88°F / 31°C, add the calcium chloride and rennet mixtures and continue to slowly heat to 105°F / 40.5°C, stirring every few minutes. At this point, you should begin to see curds separating from whey.

Once the liquid is at 105°F / 40.5°C, remove it from the heat, cover the pot, and wait 20 minutes. At this point, the curds should be fully separated from the whey; if not, wait a while longer.

Transfer the curds to a microwave-safe bowl using a slotted spoon, or strain out the whey and transfer it from your strainer. Squeeze as much of the whey out of the curds as possible, tipping the bowl to drain the liquid. Microwave the curds on high for 1 minute. Squeeze more of the whey out. The cheese should now be sticky; if not, continue to microwave it in 15-second increments until it is warm and sticky (but not too hot to handle).

Add ½ teaspoon (3g) flaked salt to the cheese and knead it. Microwave it for 1 more minute on high until the cheese is around 130°F / 54.4°C. Remove and stretch it, working it just like Silly Putty: stretch, fold in half, twist, and stretch again, over and over, until you’ve achieved a stringy texture.

For instructions on making mozzarella the more traditional and much more involved way, see http://cookingforgeeks.com/book/mozzarella/.

Benjamin Wolfe on Molds and Cheese

Benjamin Wolfe is an assistant professor of microbiology in the Department of Biology at Tufts University. His lab uses food microbial communities to address fundamental questions in microbial ecology and evolution.

How did you get into studying mold?

I did my PhD on fungal diversity, ecology, and evolution at Harvard and I was studying mushroom farming fungi. If you’ve ever played Mario Brothers, you’ve probably seen that red mushroom with the white dots on the top of it. That’s a real thing called Amanita. I became fascinated with fungi and for my postdoc, I had the amazing opportunity to work with the microbial diversity of cheese. I now have my own lab at Tufts University, where we’re doing a lot more work with food molds in particular.

Most of us aren’t familiar with mold other than, “Oh, that peach has gone moldy, let me throw it away.” Can you describe molds to a layperson?

Fungi live by decomposing stuff. They break down the environment that they live in and use that decomposed stuff as a way to make energy to grow. A log rotting in a forest or the bread sitting on your counter rots via mold. The mold produces enzymes that break down things in the environment to take in glucose and other sugars that they get from decomposition. All fungi have a compound called chitin that they use to build their cells, and all fungi have a network of cells called a mycelium. When you’re looking at a piece of bread that is moldy, that big fluffy cloud that’s spreading across the bread is a whole bunch of fungal cells all united together.

Which came first, the log or the mold?

One group of molds and fungi that people never really see are living in the soil, breaking down things in the soil, and they connect up with roots underground, and deliver nitrogen, phosphorus, and other compounds to the plants and in return the plants give that fungi carbon. It actually feeds them sugars from photosynthesis. What happened is that these fungi evolved first and allowed plants to colonize barren land that existed many millions of years ago and so, we do think actually the fungi came first and then came the plants. The log came after the fungi.

On the flip side, is there stuff about mold that’s dangerous?

Absolutely. They can wipe out entire crops; they can wipe out animals and infect humans. They produce compounds called mycotoxins, which can be very dangerous, and these compounds are produced for reasons we don’t totally understand. We think they produce mycotoxins to fight with other microbes, as these toxins can sometimes kill off neighboring microbes.

In the 1950s and ’60s, there were some big outbreaks of molds. In Europe, a bunch of feed given to turkeys was contaminated by a particular fungus-producing mycotoxin. All these turkeys started dying because of an Aspergillus disease, which is caused by mold. After that discovery, we realized that there are a lot of different types of places where molds can grow and produce mycotoxins. Often peanuts are screened for a mycotoxin called aflatoxins. These are pretty potent carcinogens that we need to monitor in our food systems.

How do I avoid mycotoxins at home?

Most high-risk foods we know are prone to mycotoxins are generally screened as per requirements by the US FDA. Peanut-based products in the US require regular screening for aflatoxins; they’re really the highest-risk product. There is research going on right now to try to evaluate coffee and chocolate, which both can get pretty moldy. But in general, if you’re eating food that’s been produced in a clean, safe way—which most of the things in the US are produced as such—you don’t have to worry about mycotoxins.

If you’re making your own cheese or salami, you have to be careful that you’re inoculating with beneficial molds that don’t produce mycotoxins. The whole idea of color being an indicator of the safety of molds is really not a safe thing to be using for the home fermenter. Leave fancy moldy cheese and salami production to the people who are experts.

Cheeses, salami, and you mentioned coffee and chocolate... You’re mentioning some of my favorite things!

And they’re all dependent on mold! My favorite mold in food is Aspergillus oryzae, which brings you sake and miso and soy sauce and all those wonderful Asian fermented foods.

In cheese and in salami, we also have wonderful molds. Camemberts and bries have that thick white sweater on their outside. That is a mold called Penicillium camemberti. The fungus is slowly decomposing the cheese curd that is on the inside of the cheese. It breaks down the proteins and the fats, which releases various flavors. It also makes it nice and creamy. When you look at aged salami, it’s also white and dusty on the outside because of Penicillium nalgiovense. This is another mold that is inoculated. In this case it’s more for keeping other molds off of the surface and creating this beautiful pure white product; it doesn’t add a whole lot of flavor.

Coffee and chocolate go through what is called heap fermentation. You just pile up all the cacao pods and let them rot for a little bit of time. People largely attribute the downstream flavors of things like chocolate to the yeast and bacteria that are fermenting those products.

Foods like salami and miso and cheeses are clearly fungal-dominated, and the fungi play huge roles in the flavor production of those foods.

Should you eat the rind on cheeses that have visibly moldy outsides?

If it’s a cheese that’s supposed to be moldy, then you’re probably fine. Camembert and brie are definitely supposed to have mold on the outside. In fact, they encourage you to eat it because often the flavors of the cheese are partly in the rind. Then there are cheeses where the surface is crusty and has a weird texture, very crunchy and dry and really unpleasant. I don’t recommend eating the rinds on those cheeses, but on mold-ripened cheeses, they’re called “mold-ripened” because you’re supposed to eat the mold.

If you are eating plastic-wrapped cheddar and eventually it gets moldy, be careful because you don’t know what that particular mold is. While it may appear to be only on the surface, it’s often unclear exactly how far in it’s grown, and it’s unclear if it’s producing any kind of toxins. If it’s not supposed to be moldy, I wouldn’t eat it.

Any tips for managing good molds? How we store these things must impact whether the beneficial mold is doing the right thing.

People know from watching their bread go bad that there are molds everywhere. We breathe in spores of mold all the time. You just have to create a really clean environment where you minimize all those spores that are coming down onto your product.

It’s also a seasonal thing. In the spring there’s a lot more growth in temperate regions, so there’s a higher risk of contamination then. In the fall, we get a lot of moldy “Frankencheeses,” as I like to call them, sent to our lab to be analyzed, because in the fall you have a lot of leaves dropping to the ground, there’s a lot of wind blowing spores around, and you end up getting a lot more colonization of bad molds at that time of the year as well.

What other unexpected things have you come across with mold?

Wherever you have a moldy food, you will have mites, tiny little insects that freak a lot of people out. So you’ve probably heard of cheese mites that really should be called “mold mites” because they’re not really there for the cheese. They’re there to eat the molds, but they’re also disturbing your cheese or salami surface.

A lot of cheese makers will either go through with a big vacuum cleaner or leaf blowers and blow the mites off of their cheese. It’s so ridiculous how much time and money is spent on cheese mites in the industry. I have a video that I think is adorable of a cheese mite eating mold. I think it’s great!

See http://cookingforgeeks.com/book/cheesemites/ for a video of cheese mites.

Scallops Enzymatically Wrapped in Bacon

The traditional way of making these is with toothpicks to hold the bacon against the scallop. If you can order some transglutaminase, try this recipe as an example of how to work with it. It’s cool to see bacon-wrapped scallops where the bacon just sticks to the scallop!

In a small bowl, mix roughly 2 parts water to 1 part transglutaminase by weight to create a thick slurry.

On a plate that will fit in your fridge, lay out:

Using a brush, coat one side of each piece of bacon with the slurry. Place a scallop on the bacon and roll the bacon around the scallop. Repeat for each scallop and transfer them to the fridge for at least 2 hours to allow the transglutaminase to set.

After resting, the bacon should be well adhered to the scallops.

Preheat your oven to 400°F / 200°C.

Place the scallops in an oven-safe hot frying pan lightly coated with oil or a small amount of butter, with one of the exposed ends down. This will cause the scallop to develop a nice brown crust, along with great flavor. After a minute or so, flip the scallops over so that the other exposed side is in contact with the pan and immediately transfer your frying pan to the oven.

Finish the scallops in the oven for about 5–8 minutes, until the bacon is done and the scallops are cooked.

Notes

• Don’t plunge your hands into the powder, and gloves are a good idea—you’re made of protein too!

• Transglutaminase requires cooking foods to proper food-safe temperatures. Unlike a single piece of steak where the center is sterile, the center of meat bonded together has been exposed to bacteria, just like ground meats.

• Since transglutaminase has the same structures as the amino acids it binds, it’s capable of binding to itself. After a few hours exposed at room temperature, it will lose its enzymatic properties, so it’s not a huge deal if you spill some on your countertop. When working with a bag of it, seal and store it in your freezer to slow the rate of the binding reaction.

• Since transglutaminase binds proteins at the molecular level, you can use it as a binder to create solids. An analogy: imagine taking wood glue and, instead of gluing two boards together, using it to create a paste with sawdust and spreading it out into a sheet. You’d end up with particleboard or chipboard—a composite that’s 99% wood, but not in the form that it occurs in nature. The same concept applies here: a purée of protein-rich foods and transglutaminase can be formed into a solid and set.

Use a pastry brush to coat one side of a strip of bacon with transglutaminase. Roll the bacon around the scallop and pinch and press the ends together for a few seconds.

A cross-sectional slice of the cooked bacon-wrapped scalloped shows the joined surface of the bacon and the scallop.

Harold McGee on Solving Food Mysteries

PHOTO OF HAROLD MCGEE USED BY PERMISSION OF KARL PETZKE

Harold McGee writes about the science of food and cooking. He is the author of the culinary classic On Food and Cooking (Scribner, 1984). His website is at http://www.curiouscook.com.

How do you go about answering a food mystery?

It depends on the nature of the mystery. It can start with and mainly involve experiments in the kitchen, doing a particular process several different ways, changing one thing at a time, and seeing what the effect is. Or it can mean going to the food science or technical literature and hunting for information that might be relevant.

A recent example of the latter would be this column I wrote for the New York Times about keeping berries and fruits longer than normal. I had been going to the farmers’ market and getting way too much fruit. It looked and tasted so good, but I couldn’t eat it all, and after a day, it would begin to mold, sometimes even in the refrigerator. I thought there might be a way to deal with this. So I drove up to UC Davis and used their online databases to search the literature for methods of controlling mold growth on produce.

I discovered that back in the 1970s some guys at one of the ARS [USDA Agricultural Research Service] stations here in California came up with a mild heat treatment that didn’t damage the fruit but did slow down substantially the growth of mold on the outside. I came back and gave it a try, and it worked. I didn’t have the knowledge or the tools to deal with it without doing some library research. I put it to the test because it’s one thing to read about something in the literature and another thing to make sure that it actually plays out that way in somebody’s kitchen.

Why not do this kind of literature search online? Is there something that UC Davis or an institution like that is able to provide researchers that they can’t get directly online back home in front of their computers?

There are wonderful resources that are available at both university and public libraries that an individual just can’t afford to subscribe to. In institutions with a food science department, there are resources on the shelf that you would never know about without going and looking, and I enjoy doing that, not necessarily to answer the question “What do people know today about X?” but more “How have people dealt with X over the centuries?”

Centuries? Can you give me an example of something from that kind of historical research?

Tomato leaves are not toxic the way people thought they were. In fact, they’re probably beneficial to eat because they bind to cholesterol and prevent us from absorbing it. The question arose: “How did we get this idea that they’re toxic if they’re not?”

I delved back as far as I could in some pretty obscure literature to try to figure that out, and that included going up to UC Davis and taking a look at a couple of books from the 17th and 18th centuries on Dutch ethnography of the Pacific. I tracked down a reference to people eating tomato leaves on an island in the Indonesian Archipelago in the 17th century. This would have been shortly after tomatoes had been introduced there because they are not native to that part of the world. That fleshes out the story of how this plant found its way around the world, how it developed a reputation, and the kinds of aesthetic judgments that people made about it.

In Europe, people didn’t eat the leaves because they thought they stank. In Central and South America, where tomatoes came from, the leaves weren’t much eaten, which I still don’t understand. Just pulling all of these bits together to me is part of the pleasure of understanding and appreciating the food that I sit down and eat at my table today. There is this tremendous depth of history and complexity that, if you delve into it, can make it even more pleasurable to eat these things.

One of the things I like best about the job I have is not so much the writing; it’s the exploring, it’s tracking down these books and reading this paragraph about people on this island centuries ago doing this with the leaves, then coming home and trying to get some sense of what that tasted like using leaves from my own backyard and the equivalent of the preserved fish that they were probably using back then to season them.

I imagine that our understanding about food is getting more refined, and we’re correcting a lot of previous misconceptions. What do you hope future research will spend time working on?

If I could name one area that I wish people with the equipment, expertise, and resources would pay more attention to and work harder on, it is flavor and the influence of different cooking methods on the ultimate experience of particular preparations. There are so many interesting questions about different ways of doing the same thing where, at the moment, basically you have your own personal experience and the experience of other people but no good, objective yardstick.

What are the real differences? Are we experiencing the same set of compounds differently because we have different sensory systems, or do, in fact, different techniques produce different sets of compounds where you happen to prefer this and I happen to prefer that? An example would be making stocks. There are some people who are real partisans of doing stocks in pressure cookers and others who think that the long, slow, barely-at-a-simmer method gives you a superior result. I’ve done both, and I like both, but they are different. I’m not sure I can really explain how they are different, so I would love to know what’s going on there.

What does the home cook need to understand about what they’re doing in the kitchen?

A scale and a good thermometer are absolutely essential if you’re going to try to understand things and do experiments carefully enough to draw real conclusions. You need to be able to measure, and temperature and weight are the main variables.

Is there something that really surprised you in the kitchen?

I suppose the one moment in my life that really confounded my expectation was the copper bowl versus glass bowl for beating egg whites. I was reading Julia Child while I was writing the book [On Food and Cooking] the first time in the late 1970s. She said that you should whip egg whites in a copper bowl because it acidifies the whites and gives you a better foam for meringue and soufflés, but the chemistry was wrong. Copper doesn’t change the pH of solutions, so I thought that since the explanation was wrong, there probably was nothing to the claim either.

Then a couple of years later, when it came time to get ready for publication, I was looking at old graphic sources for illustrations for the book. I looked at a French encyclopedia from the 17th century that had a lot of professions illustrated. One of them was a pastry kitchen. In the engraving, there was a boy beating egg whites, and it said that the boy was beating egg whites in a copper bowl to make biscuits. It specified a copper bowl, and it looked exactly like today’s copper bowls: it was hemispherical and had a ring for hanging. I thought if a French book from 200 years ago is saying the same thing that Julia Child said, then maybe I should give it a try.

I tried a glass bowl and a copper bowl side by side, so I could look at them and taste them, and the difference was huge. It took twice as long to make a foam in the copper bowl; the color was different, the texture was different, the stability was different. That was a very important moment for me. You may know that somebody else doesn’t know the chemistry, but they probably know a lot more about cooking than you do. That certainly got me to realize that I really did have to check everything I could.

A French chef told me a story. He’d made a million meringues in his life, and one day he was in the middle of whipping the egg whites in a machine. The phone rang—there was some kind of emergency and he had to go away for 15 or 20 minutes—so he just left the machine running. He came back to the best-whipped egg whites he’d ever seen in his life. His conclusion from that was, in French, “Je sais, je sais que je sais jamais.” It sounds a lot better in French than it does in English, but the English is, “I know, I know that I never know.”

Thanks to that experience with the copper bowl, that’s been my motto as well. No matter how crazy an idea sounds or how much I distrust my own senses when I do something, and it somehow seems inexplicably different from what it should be, I know that I’m never going to understand everything completely, and there’s probably a lot more to learn about whatever it is that’s going on.