Molecular Gastronomy: Discovering the “Science of Deliciousness”
I wrote this article on molecular gastronomy for Today’s Dietitian several years ago. In fact, it’s dropped off of the archives and is no longer available online. However, it’s so popular that I get requests for it all of the time, so I’ve added it to my blog. I hope you enjoy it!
Boldly going where no chef has gone before, today’s molecular gastronomists and curious cooks are following in the footsteps of food science pioneers, testing culinary traditions and myths and exploring new taste frontiers.
“It is a sad reflection that we know better the temperature inside the stars than inside a soufflé.” — Nicholas Kurti (1908-1992)
Do you ever feel at a loss for words when someone asks you what makes a soufflé swell? Or what transforms egg whites from a clear, gelatinous glob into glossy, white curlicues? Perhaps you’re even a bit curious yourself about the miracle of turning simple milk into something as complex and rich as ripe Stilton cheese.
These are exactly the questions a select number of scientists—including Hervé This, Peter Barham, Harold McGee, and the late Nicholas Kurti—have dedicated their careers to answering over the past two decades, gaining recognition in book sales, appearances in television programs, and features in newspapers and magazines. And with today’s obsession over the intricacies and nuances of every aspect of food—from obscure ingredients and cooking methods to phytonutrients and foodborne bacteria—a new generation of food science is positioned to take root and grow.
“I think people are becoming more interested in the topic, partly because books are now available which are far more understandable and interesting than the dry textbooks of old. Writers such as Harold McGee and Shirley Corriher are full of contagious enthusiasm. They write in terms which nonscientists can understand. The other reason for a growing interest in the subject is that many chefs are taking an interest and working in connection with scientists,” says Elizabeth Cawdry Thomas, who earned her certificate from the Le Cordon Bleu London Culinary Institute; taught cooking in Berkeley, Calif., for 20 years; and writes about food. The first printing in 1984 of On Food and Cooking: The Science and Lore of the Kitchen by Harold McGee was 5,000 copies. Twenty years later, the second edition had a first U.S. printing of 30,000 copies.
At the Association of Food Journalists conference in San Francisco in October 2005, McGee said, “The science of food has expanded tremendously. Also, the American palate has expanded. The experimental approach arose spontaneously on its own. I call it experimental cooking. You take ingredients developed in a particular place in a traditional way, and then you forget about the tradition. You look at the raw ingredients and ask what can we do that’s not been done before.”
A New Food Science Is Born
In the past, cooking and science have been neatly tucked away in their own compartments, with food science focused mainly on the understanding of materials and processes of industrial manufacturing and home and restaurant cooking more closely confined to a craft that had little to do with science. Sure, cooks had been documenting and refining their craft for thousands of years through recipes and practical knowledge, but those traditional cooking methods and cookbooks were riddled with mistakes and misconceptions.
History provides us with glimpses of food science pioneers in the 17th and 18th centuries, such as Antoine Lavoisier (1743-1813), who was interested in measuring the density of stock and how much solid gelatinous matter it contained, and Eugene Chevreul (1786-1889), who explored the chemical properties of fat. By the 1950s, a body of knowledge became known as food science and technology. And today a discipline called molecular gastronomy (MG) is taking food science to another level. Rather than focusing on the physical and chemical structure of ingredients in industrial settings, MG is devoted mainly to home or restaurant culinary transformations and gastronomical phenomena.
“Food science has traditionally been focused on food production and preservation. Take a look at food science and technology textbooks. They describe the major food groups, their physical and chemical properties, how they react to heat, cold, and different food preservation processes. There is a lot of food science in MG, but there is very little MG in food science,” says Christina Blais, MS, DtP, department of nutrition, University of Montreal.
McGee defines MG as the scientific study of the pleasure-giving qualities of foods, the qualities that make them more than mere nutrients—in short, the “science of deliciousness.” MG tackles issues such as describing and understanding culinary excellence in chemical and physiological terms, refining and improving these understandings, identifying ingredients and methods that are required to achieve excellence in a given food, and searching for ways of optimizing preparation beyond traditional methods.
“As gastronomy is the reasoned knowledge of all that is related to man as far as he is eating, MG is the chemical and physical study of these aspects. Of course, as culinary transformations are physical and chemical processes, they are at the core of the studies,” says Hervé This, PhD, physical chemist, College de France, Paris, and Institut National de la Recherche Agronimique. “Food science is very general…. We observed that it moved since the beginning more in two directions: the science of food and the industrial processes. But in the 1980s, culinary phenomena were forgotten. MG was created to study these phenomena, such as soufflé making, pot au feu, and choucroute.”
When Nicholas Kurti, a professor known for his work in ultra-low-temperature physics at the Clarendon Laboratory at Oxford University, England, retired in 1975, he applied his scientific knowledge to the kitchen. Kurti and This worked together, naming their new brand of food science molecular gastronomy in 1988.
“I [have been] cooking and doing chemistry since the age of 6. [In] 1980, I realized that old wives’ tales should be collected and tested experimentally. And this [has been] the basis of continuous research since that time. In 1988, I met Nicholas Kurti and we decided … that some scientific discipline was possible and needed. I proposed ‘molecular gastronomy’ and Nicholas asked for ‘and physical,’ which made the title of my PhD under my own direction—molecular and physical gastronomy. But as it was cumbersome, I decided in 1998 when Nicholas died that we would limit the title to MG and gave the name of Nicholas to the international workshops that I am [holding] in Sicily every two years or so,” says This.
Sicily for Food Science
Since 1992, International Workshops on Molecular and Physical Gastronomy in Erice, Sicily, have been a forum for professional cooks, university scientists, and food scientists to work together to advance the knowledge of restaurant and home cooking.
“I was at a meeting on a different scientific topic in Erice, Sicily, in the late ’80s when I suggested to Professor Antonino Zichichi, director of the Ettore Majorana Foundation and Center for Scientific Culture in Erice, Sicily, that the science of cooking be added to the topics in this series. He enthusiastically agreed. I suggested that Professor Nicholas Kurti, an old friend and eminent physicist from Oxford who had a passion for cooking and experimenting in the kitchen, would be the ideal scientific connection. Nicholas and I compiled a list of people from around the world to invite to the first meeting,” says Thomas of the birth of the MG workshops, noting that she has attended all but one of them. Thomas points out that while the Erice meetings on MG are very stimulating, attendance is by invitation only.
The Formula of MG
This believes that since every aspect of the environment is studied by a specific scientific discipline using the experimental method introduced by Galileo Galilei, cooking is also worthy of such scientific devotion. So what does the study of MG really look like? Begin with recipes describing culinary transformations. Modeling culinary transformations involves a comparison of food before and after cooking. Dishes are disperse systems (formerly called colloids). In a simple disperse system, gas, liquids, or solids can be the disperse phase in a continuum phase that can itself be a gas, liquid, or solid. Examples are emulsions, foams, and gels. “In whipped egg whites, air bubbles are in the middle of a liquid [the egg white]. Or in whipped cream, air bubbles are in the cream. These ‘physical systems’ are called foams, just like the foam that you have in your bath. Look at the bubbles,” This explains.
More complex disperse systems exist as well.1 Consider ice cream. The physical structure is complicated. Gas is dispersed by foaming in a condensed medium containing ice crystals, protein aggregates, sucrose crystals, and fats. But how do you name such a physical system? A multiple suspension/foam/emulsion seems a bit unwieldy. In 2003, This proposed a new formalism to describe complex disperse systems (CDS) formalism found in the kitchen. Taking into account the involved phases of food being gas, liquid, or solid, This applied letters for phases—such as G (for gas), O (for oil), W (for water), and S1 (for solid 1). Then main processes were described by a few symbols: / (for dispersed into), + (mixed with), and _ (superposed), to name a few.
To consider all possibilities, a number of k phases were chosen in the set and then symbols from the set were introduced between successive letters with the parentheses added. More rules were taken into consideration, such as the phases mixed should be written by alphabetic order, and more details were added, including the distribution of sizes of disperse structures indicated in brackets. Thus, molecular gastronomists describing aioli sauce may write:
O[10-5, 10-4]/W[d > 6 × 10-7].
CDS formalism was recently applied to hundreds of classical sauces given by the French official textbook of cooking (Gringoire & Saulnier, 1901). The sauces were studied using optical microscopy and the complete formulas were found. The formula could be simplified in many cases. Scientists discovered that all the French classical sauces belong to only 23 groups.1
The other part of the process focuses on culinary transformations. What does cooking really mean? The word is used to describe many different processes, since heat causes different changes in vegetables or meats, even if the physical structure of the plant and animal tissues is similar. Cooking is generally considered the application of a thermal treatment, but there are other scenarios involved in cooking. Ceviche obtains maceration of fish with lime juice using no heat application. Is the fish really cooked?
In 1996, This demonstrated that the strongest chemical forces established during cooking egg whites are disulfide bridges. Adding some reducing compound such as sodium borohydride to cooked egg white uncooks it by reducing the disulfide bridges. This proposed the introduction of the new word coction based on the same Indo-European root kok as in “cooking.” Of 6,357 people notified of the proposed term, 90% who answered agreed that this new word should now be used for cooking without thermal treatment.1
This believes transforming animal and plant tissues can be done in many ways and many new techniques could be introduced in the kitchen. But the way we eat is due to culture, which explains why culinary innovation is slow. Food neophobia (fear of the new) is probably responsible for part of the limited application of new techniques, but the issues of “love” and craft associated with food may trump what cooks do in the kitchen.1
“MG says, ‘let’s apply what we know about mayonnaise as an emulsion and play around with the ingredients.’ Why not replace the emulsifier with a protein—say a lobster meat—and the oil with some other kind of fat—say a melted duck fat—and the water phase with, say, parsley juice? If it tastes good, then MG has achieved its main goal: to advance the science of cooking to the next level,” says Blais.
All About Precision
MG has another main goal of testing “precisions.” Since the 1980s, many precisions have been tested, with the number of precisions now collected from French culinary books totaling more than 20,000. Examples of precisions include sayings such as “pears stay white when lemon juice is added.” Like food “myth-busters,” molecular gastronomists can answer yes through testing because ascorbic acid inhibits polyphenoloxidase (PPO) enzymes. When pears are cut, PPO transforms liberated polyphenols such as chlorogenic acid and –epicatechin into reactive quinines, which can in turn polymerize into darkened pigments. It is easy to see that the browning process is inhibited by lemon juice.1
Molecular gastronomists are testing scores of precisions—from the old wives’ tale that mayonnaise fails when made by menstruating women to whether the skin of suckling pigs has more crackling when the head of the pig is cut immediately after being roasted. Some precisions turn out to be true, some plain wrong, and others somewhere in between. For example, cooks say vinegar is less acidic when boiled, but This and Kurti showed that various vinegars yield different results, as the solutions of acetic acid in water also contain various concentrations of many other compounds, such as malic acid and lactic acid.1
Blais points out that McGee has been debunking old wives’ tales about cooking since the mid-1980s. “McGee debunked what has been taught up until recently about searing meat before [roasting]. Cooks have been taught for years—until quite recently—based on the writing of the famous Escoffier, that roast had to be seared first in order to seal in the juice. Of course, this is false. MG has brought this kind of essential knowledge into professional kitchens.”
Scientists in Chef’s Hats
While chefs have discovered empirically many successful culinary techniques and dishes, there has been very little scientific understanding in the profession. As the culinary world became more sophisticated, young chefs wanted to learn more than the tried-and-true practices that were shoved down their throats in culinary schools. They wanted to understand why foods behave the way they do.
“One reason for a growing interest in the subject is that many chefs are taking an interest and working in conjunction with scientists—Heston Blumenthal, a multi–award-winning chef in England, being one,” says Thomas. “Only last month I ate at L’Auberge Carmel in Carmel where the young chef, Walter Manzke, who has worked at El Bulli in Spain and with Alain Ducasse in Monte Carlo, was knowingly and enthusiastically using scientific principles in his superb cooking. Three-star chef in Paris, Pierre Gagnaire works closely with Hervé This, who regularly suggests scientific methods. These are just a few of the chefs who have inquiring minds and imagination.
Peter Barham, PhD, reader in physics at Bristol University, United Kingdom, and author of The Science of Cooking, believes a kitchen is just like a laboratory and cooking is just another form of experimental science. They both have chemicals and containers to mix, tools to control temperature of the reactions, and devices to measure the quantities of the chemicals for each reaction. In a sense, recipes themselves are like experiments. You measure out the ingredients, mix or react them together following instructions, and then test the result by eating it. You even test the result of your experiment against the model by checking out the photo in the cookbook. A good cook will try, try again, tweaking the experiment slightly to produce better results.
Barham has famously collaborated with Chef Blumenthal by taking MG dans la cuisine. Using traditional laboratory equipment, Blumenthal’s kitchen at The Fat Duck in Bray, Berkshire, United Kingdom, includes temperature-controlled water baths to cook fish and meats, a vacuum still to extract flavors from herbs and stocks, and temperature probes. Their kitchen experiments include testing the perfect method of cooking lamb to produce tender and juicy meat. Blumenthal extols his fascination with the science of taste and perception on his Web site (www.fatduck.co.uk), discussing experimentation such as bacon and egg ice cream. This July, Blumenthal will be awarded an Honorary Degree of Doctor of Science by The University of Reading for his dedicated research and commitment to the exploration of culinary science.
“The important thing is that some chefs find once they start to understand some of the science behind what they are doing, it can empower them to go further. The useful knowledge they gain may come from physics—for example, the way in which heat is transferred into a piece of meat as it cooks; from chemistry—for example, the different rates of the Maillard reaction depending on the temperature of the meat and the amount of sugars present; from psychology—for example, how we interpret the combination of signals from the tongue, the nose, and the eyes to generate the concept of flavor in the mouth, and so on. What is nice is that the result is that as chefs put into application the science they learn, so the food they serve gets better and better,” says Barham.
This also collaborates extensively with French chef Pierre Gagnaire, who runs Restaurant Pierre Gagnaire in Paris. Gagnaire contacted This in 2000 when he was developing his new menu, proposing they work together as a team. Together they created the Science and Cuisine menu served at an advance preview at the Cercle de l’Academie des Sciences. This gives him one invention per month, which Gagnaire posts on his Web site (www.pierre-gagnaire.com).
This believes MG has definite appeal in the culinary world. “It’s useful through technological and education applications. When you cook, if the lid has no importance on the color of green beans, why should you care about the lid?”
Face time between innovative chefs and food scientists not only provides new dishes and ways of preparing them, but it also opens a new horizon for the understanding of food. One goal of MG is that these new developments will trickle down into home kitchen use.
The Future for the New Food Science
The future of MG is exploding. “I’d like to think it is leading to a revolution in the way we eat. Some years ago, the Nouvelle Cuisine changed food here in the UK. Hopefully MG will have at least as much impact through Europe and the USA,” says Barham.
A number of culinary schools now offer experimental courses that investigate cooking and encourage critical thinking. The EU recently backed a three-year research project, INICON (Introduction of innovative technologies in modern gastronomy for modernization of cooking).
A growing number of chefs are experimenting with industrial and laboratory tools and nontraditional flavors to bring new forms of pleasure to the table. Molecular gastronomists started realizing that labs are full of hardware perfectly suited for the chef. Barham reports that there are filtration systems for stocks and consommés that reduce preparation time by many hours or even days and the use of ultrasonic mixing devices that have the potential to make novel emulsions in development.
MG is also wide open to issues such as how and why people prefer some foods and hate others, what makes good flavor combinations, and the perceptions of aroma release. Barham reports that an example of these issues is found in the fact that potato chips need to be marketed in packages that crackle. If manufacturers market them in packages that don’t have that crisp sound, then consumers believe the chips are stale.
When you stop to ponder all that we don’t understand in the science of food, the sky is the limit for MG. “Since 1980, I have collected more than 25,000 French culinary old wives’ tales that are still to be investigated. At a speed of one culinary precision tested by month, see the future!” says This.