Internationally renowned chemist and cook Hervé This *

Photo: Associated Press / Alexandra Boulat / VII * __White-haired scientist Hervé This leans conspiratorially __over a crisp tablecloth at the Paris bistro where we are having lunch. "They have my chocolat chantilly!" he says with a chuckle. "I invented it — but it was so easy, I'm embarrassed!"

This (pronounced "Tees") came up with the formula for this confection in 1995 to prove that a scientific approach to cuisine can lead to all kinds of tasty new dishes. Most people think of whipped cream — chantilly in French — as a simple combination of heavy cream and sugar. This sees it as a specific ratio of fat, water, and gas. Measure out some chocolate into a container, stir in the other two ingredients according to a particular formula, and you've got mousse. And, yes, it's delicious.

This started his culinary career in 1980, soon after he finished his Grandes Écoles diploma in physical chemistry. One night, he invited friends to dinner and made a cheese soufflé from a recipe that said to add the egg yolks two at a time. "Because I was a rational man," he says, "I decided to put in all of the yolks together. It was a failure."

Intrigued, This began to collect what he calls "cooking precisions" — rules he gleaned from disparate sources like 19th- century cookbooks, old wives' tales, and the tricks of modern chefs. He then started testing these precisions to see which ones held up (the skin on a suckling pig really does crackle more if you chop off its head right after roasting) and which didn't (a menstruating cook won't ruin mayonnaise). For the next couple of years, This and a colleague, the late Oxford physicist Nicholas Kurti, conducted the experiments in their spare time. In 1988, the pair coined a term to describe their nascent field: molecular gastronomy.

Illustration by Pietari PostiThe name has since been applied to the kitchen wizardry of chefs like el Bulli's Ferran Adria and Alinea's Grant Achatz. But This is interested in basic culinary knowledge — not flashy preparations — and has continued to accumulate his precisions, which now number some 25,000. He also has received a PhD in the field he created, served as an adviser to the French minister of education, published several books, lectured internationally, and even been invited to join the lab of one of his fans, Nobel Prize winning molecular chemist Jean-Marie Lehn.

In 2001, This came up with a formal system of classification for what happens when foods are mixed, baked, whipped, fried, sautéed in lime juice, and so forth. It shows, for example, how the 451 classical French sauces break down into 23 distinct types. More important, the system allows the creation and pairing of billions of novel, potentially tasty dishes. To demonstrate how, This randomly generated a formula describing the physical microstructure of a previously nonexistent dish, then asked chef Pierre Gagnaire to plug real ingredients into it. The result — a bitter orange, scallop, and smoked-tea concoction — delighted Gagnaire's customers.

As This guides me through the comfortably cluttered halls around his AgroParis Tech lab, he reviews his to-do list. His team is using nuclear magnetic resonance to analyze carrot-based soup stocks and studying why green beans change color when cooked. But he says that the next big idea he wants to tackle is the role that love — of the cook for the diners, the diners for the cook, and of everyone for each other — plays in determining tastes. "Cooking for someone is a way of telling them, 'I love you.' This has to be understood, of course," This says before pausing for a second. "But first, I do my job with the carrots."

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