Chemistry in the Kitchen
Bloody Shame cocktail is thickened tomato juice foam with celery "air" float. On the plates, fresh tomato pulp mousse over mozzarella di bufala; tomato basil soup sphere, balsamic vinegar sheet and olive oil powder on crostini with basil leaf.
Vegan Chocolate Cake used no eggs or dairy products; the chocolate mint chantilly frosting is whipped chocolate and water with lecithin. The cake is garnished with agar-thickened raspberry "pearls."
In 20 years, your kitchen might have a rotary evaporator, which rapidly concentrates liquids.
Share with others:
"Ever wanted to boil water in ice? Cook an egg so the yolk is set but the white is still runny? Make 'caviar' from fruit juice, or noodles from yogurt?
"We will explore the science of molecular gastronomy through lectures and demos. We will reveal the chemistry and biochemistry of food ingredients and their preparation. With the kitchen as our laboratory, we'll delve into molecular cooking, and you will get to eat your lab results."
That was the bait in the course catalog that lured 28 students at Carnegie Mellon University to sign up for The Kitchen Chemistry Sessions, a five-week mini-course during the fall semester. It was the third offering of this new course.
Food science is a hot ticket these days. The stages for teaching it are books, national television shows and the Internet, some of it accurate, some not. Surely, this would be a fun class to audit, I thought.
With the professor's permission, I sat in on the classes, taught at Mellon Institute. I didn't understand the chemistry by a long shot, but I reveled in the creativeness of the teaching, as well as the students' remarkable transformations of food by applying chemical principles.
Subha Ranjan Das has been an assistant chemistry professor at CMU since 2006. He is interested in all things science and is also an accomplished home cook.
"Cooking for my family and friends appeals to both my inner and outer chemist," says Dr. Das, a young man who is intense, energetic and enthusiastic about all things. "I see people cooking on television shows, or writing about food on websites and blogs, and they don't explain the why of their actions. My thought is if these educated and experienced cooks are just now getting around to learning the science, why not flip that idea on its head? Why not study science first and apply those principles to an understanding of food? I decided to try to make the science palatable, literally."
Dr. Das is teaching his mini-course with the official approval and encouragement of the chemistry department, and the student response has been huge.
About that confounding name, "molecular gastronomy." Around 1987, a Catalonian Spanish chef named Ferran Adria began creating new and unusual food forms and textures by experimenting with a variety of chemical and physical techniques. His restaurant, El Bulli, is located in a Catalan coastal town near Barcelona, and the menu, a 30-course revolutionary dinner, has captured the imaginations of adventurous chefs around the world.
Through original techniques such as deconstruction, spherification, ultra-low temperature freezing and the creation of culinary foams and airs, Mr. Adria reimagined the basic characteristics of food, while celebrating and intensifying the natural flavors of his raw materials. Because of his work, restaurant cooking -- and to some extent home cooking -- has been changed forever.
Then, a self-promoting French chemistry professor and TV personality named Herve This (rhymes with crease), who had been investigating ways to improve a variety of classic French dishes, such as quiches, quenelles and souffles, claimed thereby to have created "a new scientific discipline" which he christened "molecular gastronomy." Mr. Adria loathes the term. Unfortunately, the clever name caught the attention of press and foodistas, and it has become the generic term for all new methods of food preparation that can be said to be in any way "scientific."
A better name for Mr. Adria's groundbreaking contributions to cuisine would be modernist cuisine. That is the term coined by Nathan Myhrvold, whose book, scheduled for release in December, is called "Modernist Cuisine: The Art and Science of Cooking." It is a six-volume set totaling 2,400 pages and selling for $625. According to advance information, the book "reveals science-inspired techniques for preparing food destined to reinvent cooking." Mr. Adria blurbs that "this book will change the way we understand the kitchen."
Making up the 28 students were 12 freshmen, nine sophomores, one junior and six seniors. They were science majors and non-science majors, some with cooking experience and some who didn't know what whipping an egg white meant. When asked if anyone knew how to separate an egg, one student said, "Well, you crack the shell, then ping-pong the contents of the egg, and then it separates itself."
I asked some about their kitchen experience and expectations for the class.
Emma Hartman, sophomore, chemical engineering major: "I'm living in a house this year. I hope to learn enough to make food."
Brandon Dzirko, freshman chemistry major: "Chemistry is not just practiced in the lab. I watch "Future Food" on the Green Network, and I cooked at home. My biggest success was cooking for my parents' anniversary."
Linda Dong, junior, industrial design/biology double major: "I enjoy combining science and art. I'm getting into cooking mainly because it's too expensive to eat out."
Jason Fishel, senior pre-med/creative writing major: "Last summer I cooked for the first time. The best thing I made was lemon-pepper seared tilapia."
There is no textbook for the CMU course. Students use class lecture notes and .pdf downloads and search for documents using assigned online links. Schedules and announcements are posted on the class website. Homework is by digital submission.
A typical assignment: "In catalytic hydrogenation, hydrogen atoms are added in cis positions to a double bond. Based on the mechanism of catalytic hydrogenation, suggest a way that partial hydrogenation of oil leads to trans fats."
Home cooks are taught the five food groups as dairy, meat, vegetables, fruit and grains. For these budding molecular chemists, however, the five food groups are water, fat, carbohydrates, proteins and aroma-flavor molecules.
Because he would be working with raw and fresh food, Dr. Das attended the Allegheny County Health Department's workshop and passed the test to earn his certificate as a certified food safety manager.
In a lab (aka kitchen) in Mellon Institute, the students donned aprons and safety glasses, normal lab procedures. Using foods as the working medium, Dr. Das covered a sampling of the science topics with the students: lipids (fats and oils), emulsions, foams and "airs," carbohydrates and proteins, polymers and liquid food spheres, protein structure, denaturation and enzyme action.
The students had to identify key chemical features and characteristics of basic food ingredients and explain how these properties affect and determine their handling, use and taste. They had to analyze and compare ingredients, recipes and protocols, to be able to predict the purpose of and test the effectiveness of ingredients in recipes and dishes. They used scientific principles to produce dishes by novel techniques, and then explained how they were constructed. They designed, implemented and documented their experiments, both edible and otherwise.
In the lab, students made pastes and gels with xanthan gum, agar and tapioca starch; made fruit leathers and "caviars" by dropping juices into a sodium alginate solution; focused on flavor and aroma molecules and their taste and smell receptors by using simple tools as well as sophisticated equipment.
One future-food apparatus, a rotary evaporator, can concentrate and distill liquids, but it does so under reduced pressure so that the boiling temperature is much lower than in the open atmosphere.
For the last class, students created original recipes for edible dishes to present to a panel, using the format of "Iron Chef." The final exam was held at East Liberty's Waffle Shop and broadcast live on YouTube. "I chose to do the final at the Waffle Shop to get science out to the public," Dr. Das explained.
The Waffle Shop is a restaurant that produces and broadcasts a live-streaming show of interviews with its customers. This public lab functions as an eatery, a classroom for CMU students and a TV production studio. Anyone can visit the shop on Highland Avenue at Baum Boulevard and be served a pile of waffles, along with the opportunity to talk about hot topics on camera.
Student guidelines for the final: Each "dish" or item(s) had to include at least one each of an aqueous liquid, a lipid or fat, and a carbohydrate. Protein was optional. Six teams planned their plates and submitted their lists of ingredients and materials to Professor Das, who did the shopping, then supplemented the list by raiding his own pantry. On the day of the final exam, the students transformed the ingredients in a makeshift, backroom and primitive kitchen area.
The following panelists, all from CMU, were invited to rate the food: Jon Rubin, assistant professor of art and founder of the Waffle Shop; Amy L. Burkert, teaching professor in biological sciences and vice provost for education; Marsha Lovett, associate director of faculty development for the Eberly Center for Teaching Excellence and associate research professor in psychology; Linda A. Peteanu, associate professor of chemistry; and David Yaron, associate professor of chemistry.
In addition were two celebrity panelists who know both their food and their science: owner and Executive Chef Kevin Sousa of Salt of the Earth restaurant, and Robert L. Wolke, professor emeritus of chemistry at the University of Pittsburgh and author of "What Einstein Told His Cook: Kitchen Science Explained."
Plus me, the Paula Abdul of the panel, who in real life is Mrs. Robert L. Wolke.
"Remember, you are rating, not judging," Dr. Das advised the panel. "This is not a contest. Please rate the dishes for appearance, taste, how easy you think they were to make, and the application of scientific principles. Some, if not most, of the food will look like something it is not."
And then, up on the stage, one member of each team explained the food and the science behind it, as it was set before the panel. There was much high-fiving, fist-pumping and glee from fellow team members.
In the cocktail glass is thickened tomato juice foam with a celery "air" float. On the plate, fresh tomato-pulp mousse over mozzarella di bufala and next to it, a tomato basil soup sphere and a balsamic vinegar sheet with olive oil powder topping a crostini placed on a basil leaf.
The "egg white" is sweetened coconut milk thickened with agar, and the "yolk" is mango juice with added calcium encapsulated in a thin membrane of alginate. Whipped cream is a stand-in for Hollandaise sauce, with seared angel food cake pretending to be toast.
The vegan cake uses no eggs or dairy products, and the chocolate mint chantilly frosting is whipped chocolate and water with lecithin as an emulsifying agent. The cake is garnished with agar-thickened raspberry "pearls."
On a black plate, the "umami" comes from the tomato "leather" sheet wrapped around crumbled rice cake (for crunch) and drizzled with thickened black tea sauce. The pairing of tomato and black tea was used because the two have aroma molecules in common. On the white plate, the "sweet" is a chocolate wafer topped with basil cream and flash-frozen honeyberries.
Strawberry "leather" inari sushi cones are filled with sweet couscous, chocolate chantilly cream, caramelized peaches and green tea mousse. The wasabi is sweet green tea mixed with tapioca starch to thicken it. Slices of crystallized ginger and chocolate syrup "soy sauce" complete the dish.
The Gruyere souffle was served hot and puffy. The traditional dish, whipped in a copper bowl, highlights significant science such as incorporation of air and stabilizing a foam. The crusty bread was not kneaded, but baked in a covered enameled cast-iron Dutch oven. The cheese pairs with the strawberries in the salad because they share common aroma molecules.
In summing up, Dr. Das said, "It would have been easy for me to find a textbook and make lecture notes and be done with it. But being able to have this presentation, and especially after what the students have come up with, I am totally blown away. Today was amazing, given that no one has any culinary training (including me), and they have had only five classes with me. I like to think that the high level of creativity is because they understand the underlying chemistry and science, which was my goal. Beyond the pretty dishes, it is how much science they take away that is impressive. It is fairly advanced work, too -- if not for this food context, the chemistry topics are taught only in much higher-level classes, and typically only to science majors.
"By using their knowledge in a creative way, these 28 students have demonstrated that they have mastered some scientific knowledge. But at the end of the day, what I care about is that they had fun learning."
• Waffle Shop: waffleshop.org.
• YouTube: Search on "molecular gastronomy."
• A rotary evaporator in action: Aviary Cocktail Bar in Chicago: See YouTube video here
• "Ferran: The Inside Story of El Bulli and the Man Who Reinvented Food" by Colman Andrews (Gotham, Oct. 2010, $28). [Excerpt here.]
• "Modernist Cuisine: The Art and Science of Cooking" is a forthcoming six-volume series: modernistcuisine.com.
First Published November 4, 2010 12:00 am