(Feb. 16) Grant Achatz, chef/partner of Trio Restaurant, Evanston, Ill., believes sous-vide cooking is a greatly underused technique in the U.S., though it is popular in Europe. He came to Trio from the French Laundry restaurant, Yountville, Calif., where he was sous chef under chef Thomas Keller. Food & Wine magazine named Achatz as one of its Top Ten Best New Chefs for 2002. He also is a 2003 James Beard Rising Star Chef winner.

Produce Concepts asked him a few questions about his popular sous-vide cooking.

Q: Describe sous-vide cooking and your use of it.

A: It’s cooking of food in a vacuum-sealed bag in the medium of water. We’ve been doing it religiously here since I came about 2½ years ago to about 70% of the food brought into this restaurant. It’s a very precise way of cooking in which you control the temperature and cooking time. With an artichoke, for example, if you set the temperature at 175 degrees and keep it in for three hours, we know the artichoke will still retain some structural integrity and won’t become mushy, as opposed to simmering.

Q: What tools are required?

A: You need a Cryovac machine. You could start with an inexpensive Foodsaver tabletop model. You also need an electronic thermometer you can put in a water bath to monitor the temperature to the degree.

Q: What are the benefits of using the technique with fruits and vegetables?

A: It prevents oxidation of things like artichokes and potatoes. It also helps the items maintain their structural integrity. It allows you to cook without moisture, so the items don’t become waterlogged. It’s a clean way to cook. You’re not dirtying anything, and there’s no danger of burning or scorching anything.

Q: What do you include in the bag with the food?

A: You can cook without any moisture in the bag. If you want to make a puree with chestnuts or potatoes, for example, you avoid a waterlogged purée. It allows you to introduce flavored liquid you want. You can add butter or cream and therefore have a richer, more flavorful purée. You also can add other flavors in the bag, like olive oil, herbs, garlic or nuts. You can add something aromatic or a spice that will be absorbed in the cooking, like a marination.

Q: What are the flavor benefits?

A: You’re capturing the essence of the food you’re putting into the bag. If you’re cooking fennel, all the liquorice/anise flavors aren’t evaporating. Also, if you don’t introduce dilution liquid in the process, the end result will be more flavorful.

Q: Are there any other applications of sous-veed cooking?

A: To produce juice, seal and cook the fruit, take it out of the bag and run over it with a rolling pin. Then put it in a wine press to squeeze the juice out. It helps prevent scorching, you get higher yields and you’re not dealing with all the inconvenience of cooking fruits.