You could call it tart grape juice or the latest answer to balsamic vinegar
San Francisco chef Gary Danko, winner of the 1995 James Beard award for best California chef, waxes enthusiastic about fruity-tart verjus, the unfermented juice of unripe wine grapes.
"It's delicate enough to make a salad dressing that you want to pair with wine. You can use verjus to deglaze a roasting pan for a sauce, in a marinade or baste for meats, even in a spritzer. Because of the lack of big acid in verjus, dressings and sauces need a lot less fat to tame them."
This happy by-product of winemaking has been popular in Europe for centuries. When growers thin their grapes (to concentrate the flavor of the remaining grapes), the thinnings are pressed to make verjus (pronounced ver- joo). Now two California producers are bringing verjus to the kitchens of Western chefs and home cooks.
The product from Fusion Foods, called Napa Valley Verjus, is the most widely available. If a specialty foods store in your area doesn't carry it, order by mail; call (707) 963-0206. A 750-ml. bottle costs $9.95, a 375-ml. bottle $6.95, plus shipping. Navarro Vineyards sells verjus by mail only ― a 750-ml. bottle costs $7.50, a 375-ml. bottle $4.75, plus shipping; call (800) 537-9463. Other wineries occasionally sell verjus at their tasting rooms.
Once opened, verjus keeps one to two weeks in the refrigerator. For longer storage, just freeze it in ice cube trays, then transfer the cubes to an airtight container.
Gary Danko shares these quick suggestions for enjoying verjus.
Verjus vinaigrette. Combine 1/2 cup verjus, 1 tablespoon extra-virgin olive oil, 2 teaspoons minced shallot, 1/4 teaspoon minced garlic, and salt and pepper to taste. Serve over mixed salad greens.
Verjus fruit salad. Splash verjus over your favorite combination of fruit (use about 3 tablespoons of verjus per 21/2 cups of fruit, such as bananas, apples, grapes, and kiwi fruit).
Verjus spritzer. Place 2 orange slices in a large ice-filled glass. Pour 1 cup unflavored sparkling water and 1/4 cup verjus on top; stir to blend.