Kitchen Chemistry | July 7, 2008 Issue - Vol. 86 Issue 27 | Chemical & Engineering News
Volume 86 Issue 27 | pp. 26-30
Issue Date: July 7, 2008

Kitchen Chemistry

Our love of food is helping bring science to the masses
Department: Science & Technology
High-Tech Cooking
Chefs at Alinea gelatinize black truffle juice for a ravioli dish.
Credit: Bethany Halford/C&EN
High-Tech Cooking
Chefs at Alinea gelatinize black truffle juice for a ravioli dish.
Credit: Bethany Halford/C&EN

The next time you prepare dinner for your family, Kent Kirshenbaum hopes you'll be thinking about cooking on the molecular level. He wants the common cook to understand the difference between basting a turkey with an oil-based sauce versus a water-based sauce, to consider how the functional groups on sugar molecules interact when onions brown, and to know that at a certain temperature the proteins in an egg white begin to unfold and coagulate while the yolk remains runny.

"I want to transform the way people use their brains when they go into the kitchen," says Kirshenbaum, a chemistry professor at New York University (NYU).

Kirshenbaum's mission is to engage the general public in science while adding a level of precision to the art of cooking. He's encouraging people to think more often about the chemical and physical transformation happening in their frying pans or ovens, with the help of pastry chef Will Goldfarb and Amy Bentley of NYU's department of nutrition, food studies, and public health. Last year, the trio launched the Experimental Cuisine Collective (ECC), which holds monthly workshops that bring together scientists, chefs, and diners to explore the intersection of science and cooking.

ECC is part of a broader movement to use science to improve the quality of what comes out of the kitchen. That movement has trickled down from the galleys of the most avant-garde restaurants in the world, like Spain's el Bulli and Chicago's Alinea, where chefs are using technology and unconventional ingredients to create fanciful dishes, to the back room of your neighborhood bistro, where a line cook is interested in poaching eggs in a consistent manner. The trend is even starting to reach the countertops of chowhounds and Food Network fans keen on baking the perfect sponge cake.

As a result, science—particularly chemistry—is entering the lexicon of the culinary world. It's common these days for chefs to talk about the Maillard reaction, when the carbonyl group of a sugar reacts with an amino acid to form an intermediate that can result in a range of flavor molecules, or the use of calcium chloride and sodium alginate to make spheres—often compared to caviar—out of a flavored liquid. Two chefs, Goldfarb and el Bulli's Ferran AdriÀ, have even launched lines of kitchen chemicals.

ECC got its start after Kirshenbaum applied for a National Science Foundation grant to support his research in biomimetics, and the agency asked him to design a more imaginative outreach program to draw in the greater community.

He says NSF's request really pushed him to think outside the box. He asked himself: "How do you engage the public in polymer chemistry?" The answer: Everyone can relate to food, and polymers are ubiquitous in food. After all, starches are nothing more than sugar polymers, and thickeners and stabilizers such as alginates and food gums are simply complex polymers of carbohydrates.

At the same time, Kirshenbaum recognized the growing trend for upscale restaurants to apply the techniques of "molecular gastronomy," which is highly reliant on chemistry to produce dishes that push the boundaries of our perception of taste. Looking around his hometown of New York, he realized there were several local high-profile chefs, including Goldfarb, experimenting with technology.

Kirshenbaum typed up a two-page proposal outlining the general idea of ECC and walked the 10 or so blocks from his chemistry lab in Greenwich Village to Goldfarb's now-shuttered restaurant, Room 4 Dessert.

Cuisine And Chemistry
Kirshenbaum explores polymers in the lab and in the kitchen.
Credit: Lisa Jarvis/C&EN
Cuisine And Chemistry
Kirshenbaum explores polymers in the lab and in the kitchen.
Credit: Lisa Jarvis/C&EN

The image is priceless: the lanky, floppy-haired professor who once was featured in Time Out New York as the real-life version of John Frink, a scientist and college professor from "The Simpsons," strolling into the restaurant to hand Goldfarb the letter. In an age when the Food Network and Bravo's "Top Chef" have raised chefs to the level of B-list celebrities, it was an audacious move.

And a move that worked. In fact, Goldfarb says he expected—and was waiting for—someone like Kirshenbaum to walk through his door. It seems as much as scientists needed the culinary world to engage the public, the culinary world was ready for scientists to collaborate to better understand and expand the boundaries of cooking. NSF was on board with the plan, providing a small grant that, along with money from NYU, has funded the venture.

Along with Bentley, the two launched ECC in April 2007, with a strategic workshop that brought together Hervé This, the French physical chemist who had earlier coined the term "molecular gastronomy;" Wylie Dufresne, the chef-owner of WD-50, a New York City restaurant known for its use of technology to make whimsical dishes; Robert F. Margolskee, professor of neuroscience at Mount Sinai School of Medicine; and food writer Mitchell Davis.

The assortment of scientists and chefs on the panel at the first ECC meeting is representative of the kinds of speakers the group has since attracted to its monthly discussions. The sessions seem to alternate between a chef, who teaches the audience about a particular topic in cooking with a scientific slant, and scientists, who talk about general concepts in chemistry as they relate to cooking.

The launch of ECC was well-timed. Many cooking schools are incorporating "food technology" programs into their curricula. Meanwhile, at-home chefs are starting to experiment with advanced techniques like sous vide, a method of cooking food in a vacuum-sealed bag at a low, constant temperature that, if done right, allows a piece of meat or fish to be perfectly heated.

David Arnold, head of the recently launched food technology program at the French Culinary Institute (FCI), in New York City, has been a leader in translating the science of the cooking process to students. Although his course is not required for culinary students, many seem eager to take it. It's not just about learning cool tricks, either. Students are definitely interested in learning how to use a vacuum to make a gin-and-tonic-soaked cucumber, but they seem equally excited about practical concepts that can help them prepare traditional dishes with greater consistency. The topics that Arnold covers range from subjects as basic as heat—how it is transferred and how it affects plant versus animal tissues—to those as advanced as cooking under a vacuum.

Arnold's course includes a level of trial and error that is highly reminiscent of the lab. In a typical class, he might show students the difference between an egg cooked in a water bath held at 57 ºC, when it is functionally raw, to one at 62 ºC, when the white is virtually set but the yolk is still runny. He continues, degree by degree, until he finally plates an egg cooked at 66 ºC, when both the yolk and white are gently cooked and the entire egg is pliable like silly putty. A degree more, and the yolk begins to harden. All the while, the students consider when proteins are denaturing, as well as the effect of the balance of proteins, water, and lipids in each part of the egg on the rate of coagulation.

Cooking schools are also teaching more advanced techniques, where chemicals—emulsifiers like lecithin, thickeners like xanthan gum, and gellifiers like methylcellulose—are used to create dishes that defy the diner's perception of taste. In fact, hydrocolloids have become ubiquitous in restaurant kitchens, chefs say. "A lot of modern gastronomy happens to employ ingredients that are chemically derived, and some of those are used by large food groups, such as Kraft and Sara Lee, to make food on a large scale," says Grant Achatz, chef and owner of Chicago's Alinea. "Now, you have chefs doing fine dining using these ingredients to create interesting textures and previously unattainable flavors. That's a great avenue of creativity."

Chefs are also starting to use equipment that would more likely be found in a lab than a kitchen. Philip Preston, president of temperature-control equipment company Polyscience, has been an indispensible resource for chefs. He began working with Alinea's Achatz, first on a thermal immersion circulator for the kitchen and later on more fanciful equipment such as an antigriddle. The former is a device that can be dropped into a pan to create a water bath, and the antigriddle allows chefs to rapidly freeze the outside of a sauce or puree, making it solid or crunchy, while leaving the inside creamy. One can imagine the delight in serving up a flash-frozen hot chocolate or Preston's favorite, a crème anglaise lollipop.

Preston has adapted that lab equipment for the culinary industry, and interest has taken off. "Since many of the processes that take place in a kitchen are the same as those in a lab, it has been a natural fit," he says. "Heating and cooling are essential to a kitchen, but never before has laboratory precision been applied to cooking."

Indeed, thermal immersion circulators are becoming commonplace in restaurants, and Preston believes they could soon be accessible to home kitchens. As interest in the equipment has risen, the cost has dropped over the past four years from just over $1,200 to below $900, Preston says. "We've been working very diligently to engineer the immersion circulator to make it more affordable, even down to the home cook level," he adds.

Yet as all this equipment and chemistry is becoming more common in kitchens, some have challenged their use. There has been backlash from chefs and consumers alike, who believe using science—and more importantly, chemicals—deviates from the art of cooking and detracts from the beauty of ingredients in their natural state.

FCI's Arnold, who also frequently collaborates with NYU's Kirshenbaum to solve kitchen questions, recently sat on an ECC panel that addressed those criticisms. Along with Goldfarb, Vice President of Culinary Arts Nils Norén, chef Heather Carlucci, and food writer Bret Thorn, the panel explored how best to apply science in cooking. The best uses of these new ingredients and technologies are the ones that consumers are not even aware of, Arnold told the audience.

A common misconception is that "if you care about technology, you don't care about the ingredient," Norén says. Yet using an immersion circulator to make a perfectly marinated and cooked piece of steak doesn't change the integrity of the ingredients themselves, the chefs argued. Rather, technology is simply used to improve the consistency of the process. Likewise, using a bit of gellan or xanthan gum in a purée can help it retain its liquid without changing the flavor.

Philosophical discussions on the place of science in cooking aside, ECC is helping to shift the conversation about chemistry and food away from merely an exercise in the esoteric—how to use sodium alginate to make faux caviar or how to use liquid nitrogen to make ice cream—toward one that is accessible to a wider audience.

For example, Rose Levy Beranbaum, author of "The Cake Bible" and "The Bread Bible," presented an amazingly comprehensive explanation of flour during the group's January meeting. Bread is about as basic as it gets in terms of its ingredients, but the baking process itself is quite complex. She went through the wide varieties of flour, how they differ in terms of protein content, which can range from 8 to 14%, and what that means in terms of texture, flavor, and lift. She threw out phrases and words like "phenolic acid," which is responsible for the bitterness of whole wheat flour, and "glutenin" and "gliadin," the two proteins in flour that form gluten. She went on to explain how the ratio of those proteins influences the density of bread because gluten can absorb three times its weight in water. In the end, she made the perfect sponge cake, weighing and timing the addition of ingredients with the precision of an analytical chemist.

The roughly 80 audience members—some chefs, but many simply fans of baking and of Levy Beranbaum's cookbooks—were surprisingly well versed in the science of their craft. They also appeared genuinely interested in thinking about the chemistry of the baking process and how to apply science to get better results in the kitchen.

That kind of discussion—troubleshooting in the kitchen, defining the chemical makeup of ingredients, considering how those ingredients interact, and introducing concepts like reproducibility and hypothesis testing—is what Kirshenbaum hopes ECC can encourage. Although others involved in the group may have different goals, his primary objective is to engage a wider audience in chemistry.

Kirshenbaum also hopes to attract more chemists to the process of translating scientific jargon into words the layperson can understand and to answer questions that crop up in the kitchen. He says a smattering of other scientists have gotten involved with the group, but so far he has had to actively seek out collaborators.

"Chefs and home cooks are appropriately averse to radically new things, especially those they can't pronounce," Kirshenbaum says. For chemists today, he adds, there's a growing opportunity to help the public become more familiar with new ingredients while introducing them to a little science along the way.


More On This Topic

  • Kitchen Chemistry
  • Our love of food is helping bring science to the masses
  • Formula Of Food
  • Molecular Gastronomist Hervé This Tries To Define What We Eat
  • Food For Thought
  • A student finds a way to incorporate his love of science and food in his graduate work

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