Food, with a side of science

Question: When making mayonnaise from scratch, after adding oil, egg and lemon juice to a bowl, what's the best way to mix it -- with a whisk or a fork?

Answer: Two whisks, bien sûr. The wire loops of the whisk divide the oil droplets with each motion more effectively than forks. Two whisks are twice as efficient, but still not the best. "In my lab, when we want to make an emulsion, we use an ultrasonic box," says physical chemist Hervé This (pronounced "Teece"), whose work space is filled with both standard lab tools and cooking pots.



Hervé This is one of the few individuals at the center of a world-wide Molecular Gastronomy movement, in which scientists tease out the scientific processes that underlie everyday cooking tasks. Hervé This' work isn't restricted to a lab -- he is a television personality and popular author in France, and Columbia University Press has released an English version of his book Molecular Gastronomy: Exploring the Science of Flavor. This month, he presented his work during one of the food lectures hosted by the New York Academy of Sciences.

Anyone who sits down with This must be prepared to talk about food for hours. During my visit, he tells me how to uncook an egg with sodium borohydride, which uncoils the disulfide bridges made by heat. He points to a notebook pages filled with calculations, all designed to unlock the scientific secrets of food. "This is my daily life."

Back in Paris, a list of students is waiting to work with him at the Collège de France, where Nobel-prize winning chemist Jean-Marie Lehn hired him to create a lab devoted to the science of cooking. His current students are now preparing theses on the effect of flambé on food, the makeup of carrot stock, and color change in cooked green beans.

Hervé This has studied 1,250 cookbooks and gathered about 25,000 scientific questions that he'd like to address, proving or disproving chefs' tricks of the trade, wives' tales, and kitchen proverbs. It's a large number, he says, but an important one, since he's found that cookbook writers have passed along many inaccuracies.

For instance, This found what he believes is the best way to avoid lumps when making a béchamel sauce. Cooks have debated for centuries whether the roux (cooked butter and flour) should be added to milk, and whether the milk should be hot or cold. One of starch's polymers is not water soluble and another is soluble only in hot water. Dissolving starch in hot water creates a gel that makes lumps. The solution? Add the roux to cold milk. Voilá.

Hervé This has also figured out how to use a chemist's separating funnel to isolate the aromatic molecules in mushrooms, which he uses to create scented water that can become part of a flavored emulsion.

This says his data are meant to help cooks create many dishes more efficiently, without needless steps and ingredients that offer nothing to the end result. For example, while many recipes for chocolate mousse include egg, he says the dessert is simply an emulsion of fat and water, with air to make it foamy. In other words, it's best to leave the eggs out. "I don't understand why chefs use eggs," This says. "It's expensive and it's useless."

This has published his findings in scientific and popular journals including EMBO Reports, the British Journal of Nutrition, and Pour la Science magazine, the French edition of Scientific American, where he writes a monthly column about gastronomy.

He isn't the only scientist who is taking a close look at cooking. Recently, New York University Assistant Professor of Chemistry Kent Kirshenbaum teamed up with chef Will Goldfarb to bring experts together to discuss the intersection of science, cooking and eating. Often they are talking about the same thing, but with different vocabulary, says Kirshenbaum, who specializes in the architecture of polymer chains. "I think of these as reagents. He thinks of them as ingredients."

Kent Steinriede
mail@the-scientist.com

Image: Hervé This, by Kent Steinriede.


Links within this article:

K. Thomas, "From chemist to chef," The Scientist, November 3, 2006.
http://www.the-scientist.com/news/display/27998/

H. This, "Molecular gastronomy: A scientific look to cooking."
http://www.college-de-france.fr/

H. This, Molecular Gastronomy: Exploring the Science of Flavor, Columbia University Press, 2005.
http://www.amazon.com/

NYAS food lectures
http://www.nyas.org/

La gastronomie moléculaire
http://www.inra.fr/

Jean-Marie Lehn
http://nobelprize.org/

H. This, "Food for tomorrow? How the scientific discipline of molecular gastronomy could change the way we eat," EMBO Reports, November 2006.
http://www.ncbi.nlm.nih.gov/

H. This, "Modelling dishes and exploring culinary 'precisions': the two issues of molecular gastronomy," British Journal of Nutrition, April 2005.
http://www.the-scientist.com/pubmed/15877887

H. This, "Sauce hollandaise," Pour La Science, May 2007
http://www.pourlascience.com/

Experiment Cuisine Collective
http://www.experimentalcuisine.org

Kent Kirshenbaum
http://chemistry.fas.nyu.edu/object/kentkirshenbaum.html