Tell me, what does coriander (or cilantro) taste like to you? Do you love it or loathe it? The majority of people, it has to be said, like its fresh, fragrant or citrusy characteristics. Others, by contrast, are convinced that it tastes soapy (some even describe spinach as soapy too). It reminds them of dirt, bugs or mould, they say. Those in the latter camp will typically avoid any food containing what John Gerard, writing back in 1597, called a ‘very stinking herbe’ with leaves of ‘venemous quality.’ So who is correct? What does coriander really taste of?

Both sides are right, though more of the population fall into the former category. Most of us—80% or more—are likers, the exact figure depending on the ethno-cultural group tested. Are those on the soapy side of the spectrum simply unable to detect one of the many compounds that make up the distinctive flavor of coriander? Or perhaps those on the citrusy side are anosmic to something (‘anosmia’ being the technical name for being unable to smell some volatile chemical or other). No one knows for sure! What is more, there is even uncertainty about whether that soapy sensation should itself be characterized as a taste, an aroma or something else entirely. Whatever it is, it doesn’t seem to fit any of the commonly recognized basic tastes.

It is worth noting here that something like one in every two people can’t smell androstenone, an odorous steroid derived from testosterone. They are anosmic to this particular volatile organic molecule. Meanwhile 35% of the population find that it has a very powerful—and deeply unpleasant—stale, sweaty, urine smell. (This is the reason why male pigs are castrated, i.e., to minimize the unpleasant aroma known as ‘boar taint.’) Worse still, the individuals in this group tend to be exquisitely sensitive to this compound; some can detect it at concentrations of less than 200 parts per trillion. The remaining 15% or so of the population, well, they say that it smells sweetly floral, musky and/or woody. Some people (like me) experience the smell simply as chemical-like. Same molecule: completely different experience!

The prevalence of these genetic differences in the worlds of taste/flavour perception varies by region and culture. So, if you had to guess, in which part of the world do you think the likelihood of people perceiving the urinous note in their uncastrated pork meat would be highest? I have heard that it’s the Middle East—i.e., exactly the place where religion bans pork as a legitimate source of food. Just mere coincidence, you think? Seems unlikely, doesn’t it?

Coriander and androstenone are just the tip of the iceberg as far as genetically determined differences are concerned. That is to say, every one of us is anosmic to some number of compounds, many of which are associated with food. So, for instance, our sensitivity to isovaleric acid (a distinctive sweaty note in cheese), ß-ionone (a pleasant floral note added to many food and drink products; think of the fragrance of violets), isobutyraldehyde (which smells of malt) and cis-3-hexen-1-ol (which gives food and drink a grassy note) all show a significant degree of genetic variation, and roughly 1% of the population are unable to smell vanilla.

What I’m hinting at is that we all live in very different taste worlds. Some people are able to detect bitterness in food and drink where others taste nothing (this group are commonly referred to as supertasters). Supertasters may have as many as sixteen times more papillae on the front of their tongue as others (known as non-tasters). Not only do people vary in terms of their sensitivity to bitterness but also—to a less pronounced degree—in terms of their perception of saltiness, sweetness, sourness and oral texture. Taster status, like odour sensitivity, is largely heritable (i.e., genetically determined). In fact, back in the 1930s, scientists were thinking of using this taste test as a paternity test. And beyond these individual differences in sensitivity to the basic tastes, we all vary quite markedly in terms of our hedonic responses too. So, for example, there are those who are sweet likers, whereas others (including myself) are best classified as being more ambivalent about sweetness.

But why should bitterness be the taste for which individual differences are most pronounced? Why are the individual differences not so apparent for the salt, sweet or sour tastes? It is likely that individual differences in sensitivity to bitterness may have been especially important for our ancestors. In times of plenty, the supertasters would have had a competitive advantage, since they would be unlikely to ingest something bitter and hence potentially poisonous. By contrast, in lean times, it would have been the non-tasters who had a slight competitive advantage, since they would have been more likely to ingest those bitter foodstuffs that happened not to be poisonous and hence less likely to starve to death. It is a little harder to make such an argument for the other tastes.

However, a liking for bitter-tasting foods (associated with supertaster status) also correlates with psychopathic tendencies! Or, as the authors of one recent study put it: ‘General bitter taste preferences emerged as a robust predictor for Machiavellianism, psychopathy, narcissism and everyday sadism.’ Though, of course, it is important to note that correlation is not causation—you are not necessarily a psychopath should you be one of those who likes bitter-tasting food and drink. Intriguingly, the latest research shows that tasting something bitter can give rise to increased hostility. By contrast, tasting something sweet can apparently make you feel more romantic and increase the likelihood of you agreeing to go on a date. Even more remarkably, those who are thinking about love will rate water as tasting sweet. And going a step further, marketing professor Baba Shiv and his colleagues in California have reported that handling large amounts of money can change people’s taste thresholds. Once again, the sense of taste turns out to be so much more than merely a matter of taste.

This excerpt has been condensed from Gastrophysics: The New Science of Eating by Charles Spence, published on June 20th by Viking, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. Copyright © 2017 by Charles Spence.

“Food aversions,” muses Theroux repeatedly, “are always revealing.” And a reader of this book will find out that W.H. Auden always skipped dessert; Warren Buffett drinks six Coca-Colas a day; James Beard loathed chicken livers and wild rice; Prince hated onions unless they were chopped very finely and enjoyed his spaghetti with a glass of orange juice; and Howie Mandel refuses to eat raisins.

What can we make of all this? It is difficult to say. Theroux offers only glancing, superficial accounts of some of the current scientific and psychological research into food preferences and aversions, but no sustained analysis.

This is profoundly disappointing, because food phobias are a fascinating and worthwhile subject. For instance, Bee Wilson’s First Bite: How We Learn to Eat and John McQuaid’s Tasty: The Art and Science of What We Eat, both published in 2015, each provide much richer accounts of the current understanding of food habits and aversions. These books draw on neuroscience, psychology, evolutionary biology, anthropology, and biochemistry to tell a complex story of how our tastes are formed.

To what degree are our appetites under our control? Are we destined to be disgusted by some things and delighted by others? Could Dr. Einstein have found a way to stop worrying and learn to love beets?

McQuaid’s book tells the story of Patient B, who, at the age of 48, survived a severe brain infection that left him with amnesia and permanent damage to his insular cortex, amygdala, and hippocampus, regions of the brain associated with taste, memory, and emotion. Patient B’s ability to taste was profoundly affected by his brain injury. He could no longer distinguish between saltiness and sweetness, and although there was evidence that he retained an unconscious preference for sweetness, he lacked any conscious awareness of its qualities. His dislikes vanished too. After watching an experimenter spit out food while making retching sounds, Patient B told researchers that he believed that the food was probably delicious. He associated feelings of hunger and pleasure with vomiting. He seemed to have lost the capacity to understand disgust.

Recently, neuropsychologists have found evidence that mirror neurons in the insular cortex, a group of highly specialized brain cells that activate empathically in response to the emotional cues of others, are particularly implicated in the feeling of revulsion. These scientists argue that we are grossed out when we witness others acting grossed out—that the intensely personal response of disgust has a profoundly social element.

Appetites are not solely dictated by the brain; they are part of an internal physiological dialogue, a relay between mouth and belly and mind about whether to eat something and whether to keep on eating it. In First Bite, Wilson documents the search for hormonal biomarkers that regulate feelings of hunger and satiety—the chemical signals that tell us when to eat and when to stop—describing genetic conditions such as Prader-Willi syndrome, in which an overproduction of the hormone ghrelin leads to an overwhelming and insatiable feeling of hunger. People with this and related conditions are often dangerously obese. Genes are also thought to play a major role in other eating disorders, such as anorexia nervosa, a disease that has proved extremely difficult to treat and cure.

FOOD AVERSIONS: NATURE VERSUS NURTURE

But as important as brain structures, hormones, and genes may be in determining the material conditions of our hungers and the limits of our tolerance, our specific preferences and aversions are more than hardwired genetic reflexes or evolutionary legacies. They are shaped by the cultures in which we are raised, the places we pass through, the meals we remember and those we do not.

Wilson’s book takes a particularly close look at the various ways that our experiences in infancy and early childhood shape our later habits. For instance, recent studies have found that for a brief window of time, between four and seven months, infants are highly receptive to new flavors, then become resistant to them. However, standard Western pediatric practice recommends exclusive breast or bottle feeding during this time, which may make it more difficult to introduce a variety of foods later in childhood.

McQuaid discusses a famous experiment by psychologist Paul Rozin, who wanted to understand disgust’s triggers and probe its limits. His study involved children of various ages, ranging from 3 to 12½, who were presented with scenarios of escalating levels of grossness. In one, for instance, children were offered a plate of shortbread cookies and one dead grasshopper. For another group, the researcher sprinkled the cookies with green sugar, telling the kids that it was ground-up grasshopper but “tasted just like sugar.” In the final scenario, the researcher picked up the dead grasshopper, dropped it into a cup of juice, and offered the kids a sip through a straw. Rozin found that the willingness to sample the gross food varied tremendously depending on age; younger children were much less likely to be disgusted. “The sense of disgust evolves over the course of a lifetime,” McQuaid explains.

What both Wilson’s and McQuaid’s books reveal is that biology alone can never fully explain our eating behaviors. How we were fed when we were babies, our hormone levels, and our genes may contribute to our preferences and habits, but they hardly ever tell the entire story. Wilson, a clear-eyed guide to the history and controversies around “proper” eating, shows how biology and culture combine to shape what and how we like to eat. She argues, above all, that our tastes are learned behaviors that can be reconfigured—albeit sometimes with difficulty.

How do we relearn to taste? How do we expand our flavor horizons, overcome our disgust of eggs, pickles, sushi, sweetbreads, mayonnaise, or whatever food haunts us? Wilson details a technique developed by Dr. Lucy Cooke, a child psychologist at University College London, called the tiny tastes method. Each day for two weeks, a child agrees to take a very tiny taste, a pea-size amount, of a disliked food. The child does not have to swallow it, just take a lick. Each time the child takes a taste, she gets to put a sticker on her chart. If she does not, it’s no cause for concern, as there is always the next day.

Although developed for children, the method takes advantage of a principle that applies equally well for eaters of any age: with multiple exposures to a flavor, disgust recedes and tolerance increases. The goal is to minimize stress while increasing familiarity. “Eating is a skill that each of us learns,” Wilson writes. “We retain the capacity for learning it, no matter how old we are.” This is a far more subtle, sophisticated, and humane perspective than Theroux’s factoid-based insistence that what we refuse to eat is what we are.

Photography by Steve Klise.

[Editor’s Note: Want to learn more about how each of us experiences foods and flavors differently? We’ve published an excerpt from the new book Gastrophysics: The New Science of Eating, which explores the factors that play into our overall perception and enjoyment of food.]

Cook’s Science: Synthetic biology is a not a field most people are familiar with. Can you explain, in a nutshell, what you and your colleagues do here at Ginkgo Bioworks?

Christina Agapakis: We’re interested in how to build and make stuff with biology. And it grows in this way that’s inherently sustainable and part of ecosystems. We see biology as a better way to make stuff and we see it impacting a lot of different industries as a result. At Ginkgo, the focus of the company has been on making biology easier to design, easier to engineer, and building a platform on which biological engineers can use biology to build something new.

A lot of our business today is in cultured ingredients, which is the idea that you can genetically engineer yeast to produce [specific molecules or compounds] during the process of fermentation. These are often flavors or fragrances, specialty ingredients, or even nutritional ingredients.

CS: Our team at Cook’s Science and much of the general public, is familiar with yeast and with using bacteria to ferment pickles, beets, sauerkraut, etc. How does that sort of fermentation relate to the fermentation you’re doing at Ginkgo Bioworks?

CA: It’s the same biochemical process . . . the same transformation of sugar into something else by the yeast cells. When you’re talking about beer, that’s yeast taking the sugars from barley or other grains and transforming them into alcohol, carbon dioxide, and all the flavors you get along with the beer. What we do [at Ginkgo Bioworks] is start with that process and say: What enzymes can we take from other plants or other organisms and add them to the yeast [by modifying the yeast’s DNA] so that during fermentation, some of the energy from the sugar is going to create another product as well as the alcohol and carbon dioxide.

One product that’s been made using fermentation for a long time is amino acids, especially amino acids used in animal feed. Those are produced in huge vats on a huge scale; a scale that would not have been possible if you were trying to purify amino acids from proteins from another food source. But there are other kinds of products [made using fermentation], especially in fragrances and cosmetics. There are a lot of compounds present in very small quantities in plants and extracting them has led to a situation where [companies] have farmed or harvested those plants to near-extinction, so now the resource is constrained. Now, [with synthetic biology] there’s the opportunity to be able to synthetically make these compounds at a scale that wouldn’t otherwise be possible.

CS: What are some industries or companies you’ve designed microbes for?

CA: We work with companies like Robertet, which is a flavor and fragrance company, on different ingredients. [Editor’s Note: For example, Ginkgo and Robertet are currently working to insert DNA sequences into yeast so they will produce rose scent compounds during fermentation.] During development here in the lab, we do fermentation in about 250-milliliter containers, about the size of a soda can. When a product eventually goes to full, commercial-scale fermentation, it can grow to 50,000 liters in just a couple of days, which shows you what biology can do when the yeast itself acts like the factory that makes these molecules or compounds.

CS: How would you define “synthetic” in the context of what you’re doing at Ginkgo Bioworks? Aren’t yeast technically natural organisms?

CA: That’s a really good question and a really hard question. I think how we define synthetic is so tied up in all of these philosophical and historical narratives and arguments. The organisms we’re working with are pretty close to naturally-occurring yeasts and other microbes but they have been modified. We have added or taken away genes from their genomes. And I think that difference is important . . . The question of how different [are these organisms] and at what point do they cross [the line between natural and synthetic], I  think that’s something people have to decide for themselves.

CS: How do you see synthetic biology intersecting with the culinary world: restaurants, chefs, home cooks, even consumers at the grocery store?

CA: There’s a lot that is happening, or has happened, and a lot that will happen in the future. Many ingredients or enzymes are already produced using fermentation or biotechnology, things that we don’t necessarily know or think about . . . enzymes that are used in cheese production, brewing, baking, or other kinds of preservation or transformation of food, [many of] those are already made using biotechnology. There’s a lot of potential for synthetic biology to improve the efficiency of those enzymes or find new enzymes that will enable new tastes or send things in new directions.

CS: Is there a example of the intersection between synthetic biology and food or cooking that struck you as particularly interesting?

CA: Cheese. You need enzymes to make cheese. An enzyme called chymosin is present in rennet [a complex of enzymes used to coagulate milk in cheesemaking]. Rennet, historically, has come from the stomach lining of calves, but now the majority of rennet used in cheese production comes from genetically modified fungi that are able to produce that enzyme, instead of extracting it from an animal. We’re working on other enzymes that are used in cheese production—for guiding the flavor of different types of cheese—that are also often extracted from animals. So we’re looking at ways of making them [using synthetic biology instead].

CS: So, I have to ask you about the cheese project. How did you come up with the idea to use bacteria cultured from humans to make cheese? What did you hope to learn from the experiment?

CA: About seven years ago, as a graduate student, I was part of a project called Synthetic Aesthetics, which paired synthetic biologists with artists to explore the potential connections between science and technology, and art and design. My partner was Sissel Tolaas, an odor researcher based in Berlin . . . her work is about perceiving smells in different ways and being aware of how our prejudices and emotions dictate whether we say a smell is good or bad. I was working on microbes and synthetic biology and was particularly interested in microbial communities. There are microbial communities on [human skin] that make body odors—that’s where [those odors] come from. So we started asking what are those microbes, what are the chemicals they produce, and what can we learn about them. And as we started to do that research, looking for papers on the species of bacteria [found on human skin], everything was turning up cheese. And then we realized, oh wow, there’s a connection: There’s a cheese that smells like feet!

We started digging into what people already know about this connection . . . and then at one point we said, “well, let’s just make some cheese [using bacteria cultured from people] and see what happens.” It gets a very visceral reaction, because it does feel wrong, I think, to have the bacteria go from your feet to your food. That was a feeling we wanted to explore and challenge. We wanted to ask, if we do domesticate bacteria more, if people are using microbes in their home cooking more and more . . . how is that going to change our relationship to them? How is it going to change our relationship with our own bodies and the bacteria there? Will we still draw these kinds of boundaries around ‘good’ and ‘bad’ bacteria, or will those shift, too? [Editor’s Note: I know you’re curious . . . Agapakis only sampled the cheese cultured from her own bacteria.]

CS: Tell us about your role as creative director at Ginkgo Bioworks. That’s not a title we often associate with biotechnology companies.

CA: Creative teams at technology companies [like Ginkgo Bioworks] are really thinking about the edge between science and technology and the world. How do you communicate the news stories to the general public? How do you package the stories? How do you create products that are going to make sense in the real world?

CS: Do you have a favorite microbe?

CA: [Laughing] I love them all equally. There are some bacteria that make these really gorgeous patterns as they grow [on cultured media]. It’s called Paenibacillus vortex—they make these just outrageous patterns as they spread over Petri dishes, it’s really beautiful. There’s also a [genus of] photosynthetic bacteria called Anaebena, which can do a lot of really interesting things. [They’re] also kind of multicellular in that they make these really long filaments of cells. I love bacteria that blur the boundary between single cellular and multicellular . . . when bacteria have multicellularity and these complex relationships with each other, I think it’s really beautiful.

CS: Where do you see the field of synthetic biology heading in the next 5-10 years? What kinds of products might we be eating, wearing, or using that were developed using genetically modified microbes?

CA: I think we’ll start to see new materials. [For example], there’s a company called Bolt Threads that’s producing spider silk using yeast. I think we’ll also see new flavors and new enzymes making an impact along the supply chain. I also hope to see new questions being asked about how synthetic biology can affect the culinary world or people who are trying to ferment things at home. It’s fun to think about what a chef or a home pickler would do with a specific microbe, where would they take it? This is an important element to my role . . . I think the future emerges from how people interact [with the technology] . . . using their creativity and intuition for food or flavor to take it in a new direction. There is the potential to ask: What microbes are there? How can we control them differently to add new dimensions to flavor? And then the sky’s the limit because anything can be fermented.

This interview has been condensed and edited.

Photography by Kevin White.

With the world reeling from recent developments concerning the Paris Agreement, it seems that climate change and the environment are at the forefront of the American mind. Sustainability, clean and renewable energy, and reduction in overall waste are key concepts in the battle against global warming. In recent years, even cooking has seen a movement toward zero-waste practices and “closed loop” systems as chefs feel increasing responsibility to be kind to the environment. Pop-up restaurants like Dan Barber’s wastED and sustainability-driven kitchens like Relae in Copenhagen are the vanguard of groups aiming to shift public perception of food “waste” and redefining what it means to be resourceful in cooking. But you don’t have to be a fancy-pants fine dining chef to minimize food waste in your life.  

A couple days ago, Sasha and I were going over our catalog of recipes on the Cooks Science website, and we realized that several of our recipes are pretty resourceful and waste-conscious. Take Sasha’s Creamy Corn Bucatini with Corn Ricotta and Basil, for instance. He steeps corn in milk, then uses the corn for a smooth sauce and the milk to make ricotta; he even takes the leftover whey from making the ricotta to cook the bucatini. Sasha considered every ingredient, and tried to maximize its potential to pack as much corn and dairy flavor into the dish as possible. The same can be said of Dan’s Fried Shallots and Fried Shallot Oil, in which the oil can be used to make Fried Shallot Oil Mayonnaise or Fried Shallot–Sherry Vinaigrette. Then there’s my Fresno Chile-Carrot Hot Sauce: The leftover chile-carrot-garlic mash is delicious, intensely spicy, and pungent—it’s great on sandwiches, oysters, or even as a dip. And perhaps my favorite example of re-use: Sasha’s Beet Kvass Molasses, a sweet and sour concoction using the byproduct of lacto-fermented beets.

The truth is, most of us waste a lot of food when we cook. We throw out stems, skins, ugly or blemished fruits and vegetables, and sometimes perfectly good food when we’re just tired of eating those leftovers. But more often than not, there are ways to use all that waste to make something delicious. Those vibrant green carrot tops from your local farmer’s market haul? Put them into a stock, or blend them into soup. Leftover pickle brine in a jar? Pickle some other vegetables, or use it in cocktails. Woody broccoli stems? Peel and blanch them, or cut them small to add some crunch to a salad. In fact, you should probably save most of the stems and leaves that you might otherwise discard, because they’re often packed with flavor. (Parsley stems, cilantro stems, and celery leaves sometimes provide even more flavor than the parts that you would typically use.) Vegetable and poultry trimmings can be easily saved for stocks. Bruised or overripe fruits are perfect for making a quick jam or compote. Get to the end of your Parmesan wedge? Save that rind and throw it into a simmering soup or stew for a savory boost. Have a recipe that calls for egg whites? Cure the leftover yolks and grate them on . . . everything. Stale bread makes great bread crumbs or bread pudding. And of course, leftover herbs are great for Sasha’s Fresh Herb Finishing Salts. And if all else fails and you don’t know what to do with your food scraps, I strongly encourage composting if you can do it. Sometimes you just can’t really find a good use for those leftover coffee grounds and eggshells.

The cook’s adage should probably be something like this: Do more, with less. But it’s not just about using waste for the sake of using it. Learning to coax and develop flavors out of even the most humble of ingredients is arguably the most important skill a cook can cultivate. For me, using scraps and waste isn’t just some kitschy food trend that’ll die out in a few months. It’s a more holistic way to look at food, it saves money, and it reduces my ecological footprint. It forces me to think creatively and mindfully about ingredients, and ultimately makes me a better cook.

So the next time life gives you overripe, brown bananas, make some bomb banana bread. And maybe save those peels to make some banana vinegar. Seriously. It’s good.

Photography by Steve Klise, Joe Keller, and Daniel J. van Ackere. 

3D-printed parts have made their way onto jetliners, and NASA is currently working on a 3D-printed rocket engine. In the realm of biotechnology, 3D printers have been used to make prosthetic limbs for humans and animals. There’s a prototype that 3D prints functional human skin (!) for transplanting onto burn victims’ wounds, potentially eliminating the need for skin grafts. Fashion has even gotten into the game, with designers 3D printing bespoke shoes and fabrics.

As 3D printing has started to make its way into the culinary world and a handful of chefs are experimenting with printing beautiful, edible designs, I had to wonder: Is the technology ready? Should I set aside some of my meager kitchen counter space for a 3D printer? Is 3D printing poised to revolutionize the way we eat?

PRESSING ‘PRINT’ IN THE KITCHEN

Unlike a regular, two-dimensional printer, which applies a single layer on a flat surface, a 3D printer starts with that bottom layer and then builds upward from there in a variety of materials—what’s known as additive manufacturing. It turns a digital file into a physical object. 3D printers have caused ripples among engineers because they allow for unprecedentedly rapid testing and retesting of designs. New iterations of parts or products can be 3D printed virtually on demand, eliminating the need to create new molds and casts each time and vastly speeding up the design process.

And a number of chefs have taken advantage of early iterations of edible 3D printing technology to create unique, decorative, customized elements for their guests.

Kriss Harvey, executive pastry chef at The Bazaar by José Andrés in Los Angeles, California, has used the ChefJet Pro culinary 3D printer to create life-size, three-dimensional bananas made entirely of sugar and decorated with images of Andy Warhol’s Marilyn Monroe portraits. Josiah Citrin, chef-owner of Mélisse restaurant in Santa Monica, California, has used the same 3D printer in a savory application: a modern riff on classic French onion soup. He and his team printed “croutons” made of caramelized onion powder. Inside each crouton was a ball of onion petal–wrapped burrata, which mimicked the soup’s traditional cheese topping. The croutons dissolved in diners’ bowls as hot oxtail broth was poured over them. “The broth had no onion flavor at all, but when the crouton melted, the onion flavor mixed with the broth,” Citrin explained.

Paco Pérez, chef at Enoteca Paco Pérez in Barcelona, Spain, has used a 3D printer to pipe an elaborate pattern of seafood puree onto a plate, evoking the shape of fan coral. Pérez then places other elements on the plate by hand—sea urchin, carrot foam, egg—to create the finished dish.

Other culinary professionals use 3D printers to create customized objects and tools for use in the kitchen and the dining room—similar to the printers’ traditional use. Peter Zaharatos, owner of SugarCube cafe in Long Island City, New York, uses a 3D printer, along with his background as an architect and a sculptor, to print unique, customized molds for chocolate bars. (He also 3D-printed all of the physical components of his cafe, but that’s another story.) He uses software to design what he ultimately wants the chocolate bar to look like, prints that on his 3D printer, and uses it to create a mold, which he’ll fill with chocolate to create the final product. Harvey envisions something similar: “If I can see a design in my mind’s eye [and then create a mold for it] using my 3D printer . . . that gives me an advantage over the next guy.”

Nathan Myhrvold, says Scott Heimendinger, technical director at Modernist Cuisine, “had an idea that, in addition to coming up with our own dishes, we would literally make our own ‘dishes’ . . . our own porcelain plateware.” In collaboration with Shapeways, the team 3D-printed molds that ultimately were turned into ceramic dishes.”

SOLUTIONS LOOKING FOR A PROBLEM

Considering that I love making French onion soup the old-fashioned way (in a pot) and have had good luck with store-bought plateware up to this point in my life, I had to wonder if a 3D food printer was for me—or any home cook, for that matter.

Talking to Heimendinger, I realized I’m not alone in my skepticism. He said, “3D printing of edible stuff still feels a little bit like a solution looking for a problem . . . I see a lot of [3D-printed] things and think, ‘That’s so gorgeous,’ but I wouldn’t necessarily order it off of the menu.”

To create the absinthe service, the Modernist Cuisine team used a version of the ChefJet Pro printer. It creates intricate confections by binding very thin layers of fine powdered sugar (which can be mixed with other sweet or savory powdered ingredients) with a liquid, which can be colored and flavored. If you desire detailed 3D-printed sweet treats covered with colorful patterns, the ChefJet Pro might be your cup of (sugary) tea. But while it can print elaborate, even architectural designs, the powder and liquid construction method limits your options for different textures or flavor profiles.

Other 3D food printers offer a bit more versatility. Instead of working in a bed of sugar, these printers function by extruding thin layers of food—with an appropriate consistency—out of a nozzle. The layers build vertically, creating three-dimensional shapes: trees, pyramids, dinosaurs—whatever your imagination (and your software design ability) can dream up.

Barcelona-based Natural Machines created the approximately $4,000 Foodini, an extruder-style 3D food printer, to “streamline some of cooking’s more rote activities” and “encourage people to eat more healthy foods,” according to the company’s website. The user fills stainless-steel capsules with raw ingredients and attaches an appropriate nozzle depending on the food’s texture. Suggested recipes include gnocchi, ravioli (the pasta and the filling use separate capsules), veggie burgers, pizza, quiche, crackers, and cookies, which, in most cases, still need to be cooked after printing.

After perusing some of Foodini’s creations, I’m still not clear on why I would want to make my pizza, gnocchi, or cookies using the machine. I still have to prepare all my ingredients (dough, sauce, filling, and so on), then fill the capsules, press “print,” and wait just as long for the machine to 3D-print my food as it would have taken me to shape, roll, or form everything myself. And I still have to cook it. Plus, I’ll have to wash the capsules and nozzles, which as anyone who has washed pastry piping tips can attest, is a pain. It’s not obvious to me, as Heimendinger noted, what problem, exactly, this machine is solving—it’s not saving me time, effort, or expense. And as for the health angle, unless the printer is able to physically restrain me from doing so, I’m still going to toss those gnocchi in browned butter and serve them with a salad on the side. You know, for balance.

Is your inner food geek craving something higher tech? Want even more control over the food you print? Then forget about sugar and pizza sauce and focus on food “pixels.” Hod Lipson, professor of mechanical engineering at Columbia University and author of Fabricated: The New World of 3D Printing, and his team at the Creative Machines Lab, have spent several years working on what they’re referring to as the “food printer.” Their current model can print in 12 different ingredients at once and, according to Lipson, it “assembles the food, pixel by pixel,” meaning it prints tiny dots of different ingredients side by side and layer by layer to create varied textures and flavors within a single print. “It [in essence] mixes two different materials, not using a spatula, but by placing very fine dots next to each other.” Lipson noted that these dots—which he compared to the resolution on a digital image—can range in diameter from more than 1 millimeter, for something like cookie dough, down to 200 microns for an ingredient like oil or water. Though still in the prototype phase, this sounds intriguing (or at least not something a home cook could easily achieve on her own).

In 2016, Lipson and his team partnered with chef Hervé Malivert, director of food technology at the International Culinary Center in New York City, and his students to test the food printer and exercise their culinary creativity. A mixture of cooked polenta, goat cheese, and honey was “one of the most successful recipes,” said Malivert, though he noted it took about 10 minutes to print. (“Could a similar result have been achieved with a piping bag and some patience?” I thought.) Cookie dough and pâte à choux also worked well, but for every 3D success, as with any new technology, there were just as many flops. For example, 3D printing a mousseline fish puree looked promising but, according to Malivert, “when we tried to cook [the printed mousselines], they tended to shrink and the shape changed . . . so that needed work.”

A more recent prototype is able to cook the food while it prints, using infrared heat—potentially solving chef Malivert’s shrinking mousseline conundrum. The team is currently exploring using lasers as an even more accurate cooking method, something that, according to Lipson, “is a totally unexplored part of cooking.”

Other extruder-based 3D food printers, such as the CocoJet, ChocALM, and the PancakeBot, work with specific ingredients: chocolate and pancake batter, respectively. The PancakeBot features a heated printing surface, which cooks the pancakes as you print your (barely three-dimensional) design. You still have to flip the pancakes yourself. At only $299, it’s the most affordable of the bunch, but I think I’ll hold out for a self-flipping feature and stick to making quirky pancake shapes using my trusty squeeze bottle.

THE SHAPE OF THINGS TO COME

The professionals I spoke with don’t envision 3D printing taking over restaurant or home kitchens anytime soon, due to their high costs, lengthy print times, and limited functionality. They also don’t believe 3D printers will replace the human act of cooking. “I don’t think people are going to print their whole meal . . . They’ll still do their cooking, but they might add a 3D printed [element] to add a different flavor, or for a nutritional component,” said Malivert. But with significant advances in the technology, they all agreed that it could have the potential to impact particular aspects of the food industry.

One vision is that foods could be printed based on biometric data about the individual eater and could contain computer-customized ingredients and nutrients fine-tuned for each person. According to Heimendinger, “Bespoke or customized nutrition is a great opportunity for 3D printing, not only for getting nutrients into your meal in a precise way, but also for having data and traceability on your nutritional intake, which is currently a big missing puzzle piece.”

Lipson agrees. “From a health point of view, it’s the ultimate thing. Today we tend to eat one-size-fits-all food. Imagine that you wake up in the morning and the slice of bread that you eat was baked on the spot for you, it doesn’t have any preservatives and [its ingredients are] based on your specific biometrics.”

What if 3D printers could make their way into hospitals, nursing homes, and even schools as a way to meet individual nutritional needs? Malivert imagines a hospital “having a 3D printer that’s able to print [an edible item] to meet [each patient’s] needs, that has vitamins, and that’s also nice and flavorful, maybe with a little crunch.”

Heimendinger imagines a new field of food materials science “when the technology takes a leap in scale downward. When we’re able to manipulate things at a [close to] molecular scale, we’ll be able to essentially do food material science through the use of 3D-printer-like technologies. You’ll be able to achieve some of the textures we love through new means. Imagine a French fry that is always crispy, that’s never soggy, but was never fried in oil.”

Someday we might even see printed food in space. In 2013, NASA awarded a contract to an Austin, Texas-based startup to design a 3D food printer to be used on a future manned mission to Mars to provide astronauts with freshly prepared hot meals customized to their personal nutritional needs.  

Researchers at the Massachusetts Institute of Technology recently used a 3D printer to help engineer the equivalent of “edible origami.” Thin, flat sheets of gelatin and starch transform into three-dimensional shapes—tubes, curves, even flowers—when submerged in water. The team created these intricate shapes by precisely 3D printing patterns of edible cellulose, which doesn’t absorb water, over the top gelatin layer, which quickly expands as it absorbs water. They believe their findings could help drastically reduce shipping costs for foods such as pasta by allowing them to be packaged as space-saving flat sheets that only take their final shape when cooked.

Just like any technology in its early stages, the kinks of 3D food printing still need to be ironed out. In their current state, the printers on the market today don’t appear to improve upon the abilities of cooks, both amateur and professional, to make beautiful foods that are full of flavor and with appealing textures, nor do they save time or money. However, there’s no denying the technology’s future potential. Perhaps, in the future, when you get home from work, hungry and tired, you’ll head into your kitchen and press “print,” but for now, I think I’ll save that last bit of counter space for my food processor.

Header image by Chris Hoover / Modernist Cuisine, LLC. 

Watch the video above! Then check out the full recipe for Korean Nacho Cheese Sauce and see our other nacho cheese sauce recipes below.

The broth’s been simmering ever-so-gently for hours, and the whole house is filled with a delicious smell. That’s delightful, sure, but all that aroma you’re smelling is flavorful molecules that are no longer in the soup because they have evaporated and floated into your nose.

It’s a tradeoff. Keep the pot tightly lidded—or use a pressure cooker—and the house won’t smell like much of anything, but the broth will hang on to all those flavors, and they’ll rise from the bowl when it’s served. If you compare side-by-side a broth that was cooked in a covered pot versus one that was open to the air, you’ll notice significantly more delicate aroma in the covered one.

In order for us to smell anything, molecules have to evaporate from that thing, waft through the air, and physically enter our nose or mouth. And for that to happen, the molecules have to be small and light enough to take flight and make that journey. They have to be volatile.

Sniff a clean, empty metal saucepan, or a plate, or a bowl of pure white sugar, and you won’t smell much. Sucrose, a.k.a. table sugar, is too large a molecule to evaporate. It’s nonvolatile.

The substances that give foods their smell are small, light molecules: the diacetyl that characterizes butter, the 2-acetyl-1-pyrroline of jasmine flowers and jasmine rice, the cis-3-hexenol that’s a component of fresh green vegetables, and hundreds of thousands more. Vinegar has a smell because its main ingredient, acetic acid, is volatile; other common food acids like citric, malic, and tartaric acid are nonvolatile and odorless.

The more volatile a substance is, the more readily it escapes from its surroundings by evaporating. Though it’s not a hard-and-fast rule, the smaller and lighter a molecule is, the more volatile it tends to be. And the higher the concentration of volatile molecules in the air you’re sniffing, the stronger a smell is.

Though volatiles evaporate at room temperature, they do it more and faster at higher temperatures. That’s why warm food is more flavorful than cold food: Quite a bit more of its flavor is floating out of it (and into your retronasal passage) rather than staying put.

You can separate volatile from nonvolatile molecules by encouraging the volatile ones to evaporate: most commonly, by heating them. Bring your pot of broth to a rolling boil, and more and more of the delicate fragrance molecules evaporate and fill the air. The neighbors are envious. But no matter how long and hard you boil it, when all the water is gone, everything nonvolatile is still going to be in the pot. The sticky brown sludge left behind contains the salt, the sugar, the fats, the proteins, the starches, and only those volatiles that remain dissolved in fat or enmeshed in protein gels. Everything else has flown away.

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Graphics by Jay Layman.

Tasting is an essential part of the cooking process. As cooks we all must rely on our palates to determine whether a dish needs a pinch of salt, a few grinds of pepper, or a splash of lemon juice. “More salt, more acid” is a tried-and-true seasoning directive in restaurant kitchens, and it’s a big reason why restaurant food often tastes better than average home-cooking. Why? Think of salt and acid as the volume and brightness controls on a TV. Too little salt and flavors are muted. Too little acid and a dish is dull and flat. But that adage does have its limits. A heavy hand can easily take a dish from well-seasoned to unpleasantly salty or too acerbic and sharp. Like so much in life, it all comes down to balance.

“That one bite is perfectly seasoned, but what if you ate the whole thing?” I worked for a chef who would constantly ask cooks that question when tasting their food. See, restaurant cooks rarely have the chance to eat a full portion of the composed dishes they prepare. Instead, they constantly taste their mise en place one spoonful at a time throughout the course of the workday. On its own, one spoonful of a dish could taste spot-on, but when it’s accumulated with another dozen needed to finish the portion, it could be too salty, too sweet, or too sour. One of the reasons that tasting menus and tapas-sized shareable dishes are so popular with chefs is that smaller portions help avoid the onset of “palate fatigue,” that sensation of mouth boredom experienced on the 20th bite of never-ending fettuccine alfredo at a chain Italian restaurant that shall remain nameless. It’s an important distinction to make as a cook, and it takes time and practice to understand.

As Tim and I developed recipes to accompany our recent feature article on the science of spicy foods, Hurts So Good, one of our challenges was to properly calibrate the heat levels in our dishes. Every member of the team at Cook’s Science enjoys spicy food, so none of us shied away from tastings of Tim’s hot sauce, or a round of Spicy and Numbing Sichuan Bloody Marys. During team tastings, we typically have a few bites or sips of what’s on offer—we’re not pulling Don Draper mid-day office boozy benders, and we try to limit our fried chicken intake. During this round of spicy recipe development, both Tim and I had to keep in mind the cumulative burn factor. Just as one well-seasoned bite of food might add up to a salty dish, a number of spicy bites or sips could easily become overwhelming—and not necessarily obvious if you’re just having a bite or two during a tasting.

My first test batches of Sichuan peppercorn-infused vodka for one of my Bloody Mary recipes were aggressively numbing. We all agreed the drink was over the top with its buzzy kick. I decided to cut the amount of Sichuan peppercorns in half. At the first tasting of this toned-down Sichuan Bloody Mary, a couple of us wondered if we had gone too far in the other direction, making the drink too mild. In the context of just one or two sips, this Mary was pleasantly spicy, but didn’t pack the wallop of the first iteration. However, I reminded the team that over the course of drinking a whole cocktail, or two, the Sichuan pepper buzz would build. We wanted a brunch sipper with a slow burn, not one that blew the doors off after a couple sips. So I took one for the team, and at the end of one workday drank a whole Bloody Mary in a one-person happy hour. It was far more palatable than the first version, and, by the end of the glass, I concluded it was definitely still delivering the numbing tingle we were looking for. It was a delicious sacrifice.  

Tim’s Nashville hot chicken-inspired Mole Hot Fried Chicken presented a similar topic of debate. If you’ve ever had Nashville-style hot chicken, you know the chile burn is real. Tim didn’t hold back on the heat, and the first few tastings had us all sweating and sneezing. And while the heat is a necessary part of this recipe, it also felt excessive. Getting through a full chicken thigh was a delicious but painful exercise and the cayenne heat overwhelmed any of the subtler chile and spice flavors Tim had so carefully balanced. Making fried chicken at home is an endeavor, and we agreed it would be a cruel joke to have people go through the trouble of brining, dredging, frying, and basting chicken with the chile oil, only to find that the fruit of their labor was too spicy to enjoy beyond the first few bites. Again, one bite might be bearable, but we needed to dial the heat back a bit so that people could enjoy eating a couple pieces of the richly flavorful chicken without needing to wash it down with a gallon of fire-extinguishing milk. Heat for heat’s sake is a zero-sum game in regards to flavor. By toning down the heat, and increasing the amount of aromatic spices in his mole-inspired chile oil, Tim was able to bring balance and nuanced flavor to brush over delicious fried chicken.

No matter what you’re cooking, think about how something will taste as a whole portion. If it’s a small appetizer, you may want to ratchet up the heat/salt/acid intensity to make those couple of bites stand out. But when it comes to a dish that will be enjoyed in larger portions, take a more holistic approach to seasoning to keep people coming back for more.

Photography by Kevin White and Steve Klise.

In the 1950s, a USDA chemist named Allene Jeanes was researching polysaccharides, which are large molecules composed of numerous sugar molecules strung together. Polysaccharides are often a structural component of plants and animals. Corn starch (every starch, in fact) is a polysaccharide; so is cellulose, which gives plants their rigidity, and chitin, the main ingredient in lobster shells.

Jeanes developed a way to use bacteria to produce a polysaccharide called dextran that could be used to extend limited quantities of blood for transfusions. She received several awards for the lives saved with dextran in the Korean War. Then she used a similar technique to create xanthan gum.

Xanthomonas campestris, a bacterium found on cabbage, converts sugar into a long polysaccharide. When the USDA team cultured it in large stirred vats, the result was a thick gum they called xanthan. Today, the gum is dried and ground into a powder for sale, then re-hydrated for use.

Like other hydrocolloids, xanthan’s long, string-like molecules grab onto each other in a tangled web when they get wet. That micro-scale web slows down any water that tries to flow through it. So dissolving even a very small amount of xanthan powder in a liquid raises the liquid’s viscosity. The more you add, the thicker it gets, from a gentle full-bodied mouthfeel, to a syrupy slow pour, to a jelly you need a spoon to get at.

There are a great number of hydrocolloid gums and thickeners out there: guar gum, locust bean gum, agar, pectin, carrageenan, gum arabic, and more, each with its own properties and specialties. Some of them work best at very specific temperatures or pH levels, or require the presence or absence of other ingredients like calcium or salt. Xanthan happens to be very forgiving and very easy to use, in a wide range of environments.

Its versatility makes it extremely useful in all sorts of applications. In a pureed hot sauce or ketchup, a small amount provides thickness and a smooth feel, and also helps to keep the solid and the liquid components from rapidly separating in the bottle.

It can emulsify oil and water together, which is why it’s often seen in bottled salad dressings. In ice cream, it binds water and reduces the formation of ice crystals, yielding a smoother, creamier dessert. It’s even used in the construction and oil industries, to thicken drilling fluid and concrete.

Xanthan is sold as a beige powder and is increasingly available in supermarkets. When adding it to a liquid, some care is required to disperse the powder lest it form clumps. Mixing it with another dry ingredient before adding the combination to liquid keeps the xanthan from clumping. If that’s not possible, sprinkling it slowly into a whirling blender full of liquid is a tried and true dispersal method.

For working with it in the kitchen, a high-precision scale is helpful, since xanthan is effective in small doses: no more than 1 part in 100, and usually much less. Its potency: that’s yet another reason we love this hydrocolloid.

Amidst the chaos of TV filming that Sasha is experiencing for the first time, I have been quietly frying my way through pounds and pounds of chicken. But not just any chicken: I have been developing a recipe for a spicy fried chicken to accompany our upcoming feature about spiciness. And since the departure of ATK’s undisputed, all-time greatest fried chicken queen, senior editor emeritus Diane Unger, the mantle of fried chicken warrior seems to have fallen to me. Diane’s chicken was famous for, among other things, its supremely crispy crust. In her last days here at the company—at the peak of my testing for Koji Fried Chicken—Diane left me with this cryptic (chicken) nugget of wisdom: “There’s so much more to explore . . . If you really want crispy fried chicken, cornstarch is just the tip of the iceberg.”

For years, Diane had championed wheat flour only, or a blend of wheat flour and cornstarch, for the dredges in her Southern-style fried chicken recipes. More recently, she had developed a Hawaiian-Style Fried Chicken recipe using potato starch to good effect. But that’s as far as she went. She never officially published a recipe incorporating alternative starches (tapioca, rice flour, etc.) into her dredges.

For this recipe, I needed a super crunchy coating that would hold up well to being lacquered in a flavorful chili oil without sogging out. So I thought I would rappel down the rabbit hole of dredge blends, in hope of finding a coating that would deliver crispier, crunchier fried chicken.

Classic southern fried chicken recipes call for dredging in 100 percent all-purpose flour. But the companies and restaurants that make fried chicken professionally rely on a tailor-made mix of  alternative starches to get specific results. While a portion of classic wheat flour contributes important flavor, they may add other starches to create crispier, crunchier products, with long shelf life, or perhaps a thinner, more delicate coating that shatters like glass. And there are starches specially engineered for that.     

Taking a cue from “big fried chicken” I set up four different dredge blends in a ratio of 5 parts all-purpose flour to 3 parts alternative starch—the standard ratio of starches for many of Diane’s delicious fried chicken recipes. In this case, I chose cornstarch, tapioca starch, rice flour, and potato starch. I seasoned the dredges lightly and fortified them with baking powder for added crispness and browning. After a quick brine to ensure juicy meat, I dipped the chicken in buttermilk, dredged it, and let it hydrate overnight until the coating was mostly wet-looking. Finally I fried all of the batches in 325 degrees F oil and we tasted them blind, next to a control batch dredged in 100 percent all-purpose flour for comparison.

Here’s how it all broke down, with some cursory team tasting notes:

All-Purpose Flour Only
This coating was decent. These pieces were crunchy and crispy out of the fryer, but a bit delicate. There was a slight toughness to the coating, likely due to too much gluten formation in the hydrated dredge (all-purpose flour is 10 to 12% protein). After thirty minutes, the coating was getting soggy and unappetizing.

All-Purpose Flour & Rice Flour
This crust was much more substantial than the control sample—in a good way. But tasters noted a slightly sweet flavor, a bit like stale cereal. Overall, we felt like this wasn’t the best direction for this particular application.

All-Purpose Flour & Cornstarch
This had more crunch and crispiness than the control, but the coating seemed to flake off when we bit into the chicken moreso than in the other samples. Overall, this was a solid coating, and I can see why so many recipes at ATK employ this blend. After thirty minutes, the coating appeared to stay decently crispy, with only minor patches of sogginess.

All-Purpose Flour & Tapioca Starch
This was our runner-up for favorite blend. The coating was thin, even and shattered a bit when you took a bite. After thirty minutes, this coating stayed moderately crispy, with no patches of sogginess.     

All-Purpose Flour & Potato Starch
This blend was the team’s favorite for two reasons: exceptional, satisfying crunch and crispiness, and unmatched staying power. For some, the crunch factor was a little over the top. And even after two hours, this coating stayed crispy. While a few blends produced satisfactory results, this was our clear winner in this application.

Based on this testing, it seems like I found my ideal blend for this recipe’s chicken dredge in all-purpose flour and potato starch. But what’s the reasoning here? After lots of reading—and lots of back and forth with senior editor Paul Adams—the answer is pretty complicated. (And in case you were wondering, fried chicken scientists—and even better, tempura scientists—exist.) Here is what I can gather so far: The starchy dredge absorbs water during the overnight hydration period, but it doesn’t soften up until it hits the hot frying oil.

All starch is made up of granules, and the granules are composed of two kinds of molecules, amylose and amylopectin. When it comes to a crispy coating, it’s the amylose content that really counts.

When they’re in a moist, hot environment—like a hydrated dredge that’s being deep fried—starch granules swell up allowing the amylose starch molecules to move about and separate from one another. Then, as water is evaporated during the frying process, these separate starch molecules lock into place, forming a rigid, brittle network with a porous, open structure that’s crispy.

Both cornstarch and potato starch are relatively high in amylose, at 25 percent and 22 percent, respectively. Tapioca starch is 15 to 18 percent amylose, and rice starch can be even lower. But given that we repeatedly found the potato starch sample to be crunchier than the rest, it’s clear there is more to the crispy equation than the percentage of amylose. What’s making the difference?

Of all the starches I used, potato starch has the largest starch granules (up to 75 microns compared to 5 to 20 microns for cornstarch), and accordingly, the longest amylose molecules. According to starch researcher Peter Trzasko, quoted in Food Product Design magazine, smaller molecules rapidly form a starch gel when exposed to moisture and heat, as our dredges were. Larger molecules cohere but don’t gel as readily: “[p]otato and tapioca have a molecular weight so much higher than that of corn that it actually makes it more difficult for the molecules to associate.” It seems likely that the water is more easily and thoroughly evaporated from a potato-starch dredge during frying, since it’s not trapped in a gel. The result is a denser coating with brittle crunch, and one that is less quick to retrograde and become chewy or soggy.

This paper corroborates that granule size appears to correlate positively with the perception of crunch. But it’s complicated.

I now understand the need for starch scientists. I’ve been buried in many contradictory findings after reading one too many independent studies. Part of the issue is the specificity of my recipe: I can’t find many studies that mimic or even loosely follow my exact testing conditions. Unlike a lab or academic setting, cooking doesn’t happen in a bubble. I can’t control every single variable in such a complex system as cooking. Instead, it’s useful to use scientific research to inform and guide my testing. In the end, we have to trust our palates and ask as simple question: Does this taste good? As for my fried chicken, for now I’m happy I’ve found a coating that’s undeniably crispy, crunchy, and long-lasting.

Do you have experience with alternative starches and fried chicken? Any tips or insights into the test results? Let us know in the comments below.

[Editor’s Note: Be sure to check back next week on Cook’s Science to see Tim’s final fried chicken recipe!]

Photography by Steve Klise.