Food 2.0: Chefs as chemists

By Kenneth Chang

International Herald Tribune

In September, talking to an audience of chefs from around the world,
Wylie Dufresne of WD-50 in New York waxed enthusiastic about a type of
ingredient he has been adding to his restaurant's dishes.

Not organic Waygu beef or newfound exotic spices or eye of newt and toe
of frog, but hydrocolloid gums - obscure starches and proteins usually
relegated to the lower reaches of ingredient labels on products like
Twinkies. These substances are helping Dufresne make eye-opening (and
critically acclaimed) creations like fried mayonnaise and a foie gras
that can be tied into a knot.

Chefs are using science not only to better understand their cooking, but
also to create new ways of cooking. Elsewhere, chefs have played with
lasers and liquid nitrogen. Restaurant kitchens are sometimes outfitted
with equipment adapted from scientific laboratories. And then there are
hydrocolloids that come in white bottles like chemicals.

Xanthan gum, for instance, a slime fermented by the bacteria Xanthomonas
campestris and then dried, is used in bottled salad dressing to slow the
settling of the spice particles and keep water and oil from separating.
Xanthan and other hydrocolloids are now part of the tool kit of high-end
chefs.

"These ingredients are finding more and more of a footing in the
traditional, free-standing restaurant," said Dufresne (pronounced
doo-FRAYN) at the Starchefs International Chefs Congress in New York.

He noted that the hydrocolloids he uses came from natural sources and
often had a long history in the cooking of other cultures.

"In our ongoing search of working with hydrocolloids, we're always
trying to find interesting and new things and new applications," said
Dufresne, who at times sounded as if he were talking to chemists rather
than chefs.

And rightly so. Cooking is chemistry, after all, and in recent decades
scientists have given much closer scrutiny to the transformations that
occur when foodstuffs are heated. That has debunked some longstanding
myths. Searing meat does not seal in juices, for example, but high heat
does induce chemical reactions among the proteins that make it tastier.
The experimentation with hydrocolloids represents a rare crossover
between the culinary arts and food science, two fields that at first
glance would seem to be closely related but which have been almost
separate. Food science arose in the 20th century as food companies
looked for ways to make their products survive the trek to the
supermarket and remain palatable. The long list of ingredients on a
frozen dinner represents the work of food scientists in ensuring shelf
life and approximating the taste of fresh-cooked food.

"Ten years ago, or maybe a little more than that, no chef in a serious
restaurant would be caught dead using these ingredients," said Harold
McGee, author of "On Food and Cooking" (Scribner, 2004) and the "Curious
Cook" column, which appears in the Dining section of The New York Times.
"Because they were industrial stabilizers for the most part."

Then a few chefs like Ferran Adrià in Spain and Heston Blumenthal in
England started experimenting. "They asked what can you do with these
ingredients that you can't do with other ingredients," McGee said.

Despite its imposing name, a hydrocolloid is a simple thing. A colloid
is a suspension of particles within some substance. A hydrocolloid is a
suspension of particles in water where the particles are molecules that
bind to water and to one another. The particles slow the flow of the
liquid or stop it entirely, solidifying into a gel.

Cornstarch used as a thickener is a hydrocolloid. So is plain flour. But
the properties of hydrocolloids differ widely, depending on their
molecular structure and affinity for water.

Today, Grant Achatz, chef of Alinea in Chicago, uses agar-agar, which is
a hydrocolloid made from seaweed that is best known for growing bacteria
in petri dishes, and gelatin, a more familiar hydrocolloid made from
collagen in meat, to make transparent sheets that he drapes over hot
foods. For a dish made of a confit of beef short ribs, he wanted to add
a taste of beer so he draped a veil flavored with Guinness on top - "a
thin, flavorful glaze that ensured the diner would get some beer flavor
in every bit of the dish," Achatz said. Plain gelatin would simply melt,
and ruin the effect.

Even chefs far from the avant-garde use hydrocolloids. David Kinch, the
chef of Manresa Restaurant in Los Gatos, California, known for
ultra-fresh and ultra-local ingredients, makes purees of vegetables. To
keep water from leaking out, he adds a touch of xanthan gum.

One of the dishes Dufresne presented in his Starchefs talk was what he
called "knot foie," a result of experimentation combining xanthan gum
with konjac flour, made from a tuber long used in Japanese cooking.

"We've had konjac flour in the kitchen for a long time, and we just
hadn't used it," Dufresne said. "We realized, after reading, that it has
a really interesting synergy with xanthan gum. It makes a kind of funky,
strange gel on its own, but in conjunction with xanthan gum, which on
its own won't make a gel but is just a thickener, it makes a really
interesting, very elastic product."

He continued: "So we thought, well what could we take that normally
wouldn't behave like that but would be really interesting. And almost
instantly, we came up with the idea of foie gras."

One wall of the WD-50 kitchen, with metal shelves filled with white
bottles of hydrocolloids, looks almost like a pharmacy. Dufresne's
reading material includes "Water-Soluble Polymer Applications in Foods"
and "Hydrocolloid Applications: Gum Technology in the Food and Other
Industries."

Like scientists, Dufresne and his staff experiment, recording their
observations and findings in notebooks. Using butter - much cheaper than
foie gras - they began a series of trials in May to determine the ideal
proportion of konjac to xanthan, which turned out to be 70 percent
konjac, 30 percent xanthan in a 0.65 percent concentration.

"It's a recipe," Dufresne said.

In addition to flexible butter, Dufresne also has a recipe for a butter
that does not melt in an oven. (That innovation has yet to find a place
on his menu.) The latest experiments are how to make deep-fried
hollandaise sauce, which he hopes to wrap into a variation of eggs
benedict.

To make a flexible foie, a foie gras terrine is melted into liquefied
fat, the xanthan and konjac are mixed in, and then a small amount of
water and an egg yolk, which helps keep everything evenly suspended in
the liquid, are blended in. The mixture is spread on a sheet, chilled,
cut into strands and tied into knots. Hence, knot foie.

In the question-and-answer session, one person asked why Dufresne went
to the trouble of making a foie gras terrine, a process that takes half
a day of chilling, when the next step was melting it into a liquid.

"We were trying to be true and honest to that aspect of French cooking,"
Dufresne replied. He paused before adding, "And do something kind of
crazy with it."