Walk into the organic chemistry lab of Nobel laureate Jean-Marie Lehn and you might be surprised to see that some shelves are lined with bottles labeled "salt," "mustard," and "cinnamon." There is fresh meat and fruit on the benches, and the equipment includes two ovens and a variety of cooking pans. Such are the laboratory tools of molecular gastronomist Hervé This.

A chemist by training, This is one of a small but important group of chefs and scientists who are using chemistry and physics to improve our understanding of cooking and, more importantly, they say, helping us create the desired effect at our tables.

Every other year, many of these cooking chemists gather with leading chefs and food industry members in Erice, Sicily, for the International Workshop on Molecular and Physical Gastronomy. Each meeting focuses on a different aspect of food or cooking. In 1999, the group discussed taste, even using mass spectroscopy traces to analyze different soup stocks [1]. This year, according to This, the meeting organizer, they will focus on texture, though after speaking with several of the participants, I am sure issues of taste will not be neglected.

This has also been exploring what happens when he uses different protein sources in mayonnaise. Regular mayonnaise is an emulsion of egg yolks (protein and water) and oil. As the protein denatures during mixing, it sticks to the oil droplets, stabilizing the water in the emulsion. It has long been known that for different flavors, other protein-rich ingredients can be substituted for the yolks. For example, replacing the yolks with egg whites results in a weakly flavored mayonnaise, says This, but a mayonnaise nonetheless. In fact, by understanding the chemical role of the ingredients it becomes easy to substitute new, and perhaps unexpected, ingredients such as Roquefort cheese.

But texture really comes into play with This's next set of experiments. This shows that, depending on what kind of ingredients you use in your mayonnaise, you can either get formation of a physical gel upon heating - where the oil droplets actually fuse together - or a chemical one. If This uses plain gelatin in place of the yolks and then heats the mayonnaise in a microwave, he gets a physical gel that he says resembles an "oil sponge" - which is not very appetizing. But if, instead, he makes a mayonnaise using egg whites for protein and chocolate for oil and then heats it in a microwave, he obtains a chemical gel. He calls this creation Chocolate Dispersion and says it is a wonderful, easy chocolate cake.

Shirley O. Corriher, author of Cookwise and a participant of the Erice meetings, says that thinking about cooking in terms of science has been invaluable. "Chemistry is just everywhere," she says, rattling off a list of chemically dependent cooking processes including browning foods or preventing them from getting too brown, muffins being too flat, or even muffins falling apart.

Corriher says, "My approach is strictly to use chemistry to get what you want in cooking." Her emphasis is on understanding the role of both ingredients and techniques in cooking, and she says that once you understand those basics, you can obtain the desired effect at your table. A simple example is choosing the right fat for your cookies depending on whether you want flat, crunchy ones or puffy, soft ones. With butter, which has a relatively sharp melting point, the cookies spread all at once as they are cooking, resulting in a crunchier cookie. If, instead, you use a vegetable shortening, which has a broader melting point, the cookies will spread more slowly and leave you with a puffier, softer cookie.

At the upcoming international meeting, Corriher is teaming up with Fritz Blank, chef de cuisine and owner of Deux Cheminées in Philadelphia, Pennsylvania. They are preparing a discussion on how brining meat - soaking it in salt water prior to cooking - improves its texture and results in a more tender, moister piece of meat. Both Blank and Corriher say that like any other science meeting, the molecular gastronomy is an opportunity to exchange ideas with people who are thinking about similar things from different perspectives, though Corriher laughingly acknowledges that they usually come up with more questions than answers.

If you ask Fritz Blank what the value of the chemistry of cooking is he admits, "That's the million dollar question. For me it is about understanding the mechanism of how food behaves as it cooks and we manipulate it." When he teaches culinary students, he stresses their need to understand the role of the ingredients and is concerned that "the function of knowing how to cook is waning from American culinary education," which is increasingly dependent on recipes.

However, even as he emphasizes the importance of knowing what the science is behind his cooking, Blank remarks that for him the most important issue will always be the final product, and he notes that not all of This' inventions are what he desires on his table.

But that doesn't stop This, who says, "It is very easy to invent new dishes if you are using science." For example, describing a pure chocolate mousse he invented a few years ago, called Chocolate Chantilly, This says, "If you want to make a chocolate mousse, you don't need eggs, you don't need butter, you don't need sugar. Just use chocolate and water. This dish could not be created without science because, just like the Chocolate Dispersion, this invention is based entirely on science." He continues, "There have been centuries of cooking, but this invention has not been done because they have not been using the scientific description of the food."

Whether or not This' chemistry will lead to your newest favorite recipe or not, here's a hint from This that might help your next meringue. Meringue is whipped egg whites, which, like the yolk, are composed of protein and water. Thus, in a meringue there are three ingredients: air, protein, and water. He has found that the limiting ingredient is water; so, if your meringue lacks the desired volume, add a little water and see what happens. He calculates that one egg white is enough to make one cubic meter of meringue. Has he done it? "No, the most we've made is five liters from one egg. It took two hours and we were tired."