From chemist to chef

A former biochemist has built a new career unraveling the mysteries of the kitchen

Nov 3, 2006
Kate Thomas
The great 19th century gastronome Jean Anthelme Brillat-Savarin studied chemistry before becoming the authority on all things epicurean, and in 1825 he happily announced the birth of food science: "Gastronomy has at last appeared, and all the sister sciences have made a way for it. Well; what could be refused to that which sustains us, from the cradle to the grave, which increases the gratifications of love and the confidence of friendship?" The connective tissue between science and good eating is the subject of The New York Academy of Sciences' "Science of Food" lecture series, in which wine, cheese, beer, and taste itself will be put under the microscope. The series was launched with an address on the "Science of Cooking" by culinary consultant and chemist Shirley O. Corriher, author of Cookwise: The Hows and Whys of Successful Cooking (Morrow, 1997), which won a coveted James Beard Award.For 20 years, Corriher has worked with luminaries such as Julia Child and Roland Mesnier, the White House pastry chef. When a recipe mysteriously fails, restaurant and food industry chefs turn to Corriher for help. Corriher's career path was not unlike Brillat-Savarin's; she came to food after working as a biochemist in the research laboratories at the Vanderbilt Medical School. She knew nothing about cooking until she and her husband opened a boys' boarding school and Corriher found herself catering for 140. With the measured irony that only those blessed with a southern accent can achieve, Corriher described the experience as a "trial by fire." Teenage boys are, she added, "the ultimate restaurant critics." Flummoxed by why her scrambled eggs stuck to the pan, Corriher was saved by her German mother-in-law, who taught her to pour eggs onto a hot, not a cold surface. This simple lesson was the first in a life-long course of study. "Science is an indispensable part of our everyday lives, and nowhere is that more clear than in cooking," Corriher said. "You can't be a great cook without understanding the chemical properties of food and how it interacts with other variables, such as temperature, time, and the type of cookware used." Becoming a cook, on the other hand, has taught her about the relation of theory to practice: "From chemistry I know what is supposed to happen, and I also know from my pots and pans what really happens. I take what really happens and work backwards." For Corriher, food is full of pedagogical possibility. "When you heat an egg white, it starts off translucent: you can see right through it until the protein bonds pop open. One protein runs into another with their bonds sticking out, they join together, and bam! The egg white turns white. This is chemistry you can see." It is also chemistry that you can taste. Everyone knows what happens when you overcook an egg -- it turns rubbery. The explanation? When those protein bonds first join, they trap water, but if you keep heating, the water is squeezed out entirely. This basic science also underpins the sophistication of sous-vide cooking. A fashionable and hotly debated technique, sous vide (literally "under vacuum") seals ingredients in plastic and slowly cooks them in a water bath at low temperatures. Some topnotch chefs like Alice Waters of Chez Panisse, who prefer a hands-on intimacy with ingredients, dismiss the technique. But it has found favor with other premier chefs, like Thomas Keller of The French Laundry. Cooking protein extremely gently avoids muscle-length shrinkage and substantial moisture loss, so the sous vide method can lead to sublime textures. Done incorrectly, it can also lead to botulism. Placing food in anaerobic environments preserves cell structure and amplifies flavor, but requires a kitchen run with the precision of a laboratory. Cooks need scientists to understand the thousands of elements affecting food, including color. It is a culinary truism that blue food is not appetizing. But cherries in muffins sometimes have a blue halo, red cabbage can turn blue in the sauté pan, and Corriher recalled being asked to explain why walnuts stained a chef's fish with a nasty "blue drool." The culprit was anthocyanins. Three groups of compounds give red fruits and vegetables their color. Carotenoids are relatively stable (think pumpkin), and so are betalains (think beets). But anthocyanins are what Corriher calls "the problem children." Water soluble, they also lose their red hues when made too alkaline. If red cabbage turns blue while cooking, it is because its acids have evaporated. A teaspoon of vinegar will restore its scarlet. The blue cherries have reacted with the baking powder or baking soda in the batter. Substituting acidic sour cream for milk will solve the problem. Acids will, however, be the death of green vegetables. Corriher set the scene: "There's your green bean, a happy little fellow, breathing in oxygen, breathing out CO2, just like us. He hits the hot water and he starts leaking acids like crazy. The pectic substances that hold his cell walls together begin dissolving, and before you know it, your bright green bean is army drab."Nothing about Corriher's career in the kitchen is drab, and the comfortable fellowship she feels with the respiring green bean has everything to do with communion among scientists, cooks and eaters -- "the gratifications of love and the confidence of friendship" that Brillat-Savarin celebrated. Kate Thomas mail@the-scientist.comKate Thomas is a professor of English at Bryn Mawr College, where she teaches a course on literature and the history of food.Links within this article:Jean Anthelme Brillat-Savarin"Science of Food" lecture series O. Corriher The Secrets of Cooking Revealed (Morrow, 1997)