Pucker Up for Tamarind : Exotic: This tropical seed pod, tasting of fresh lime juice and pureed prunes, makes everything from soft drinks to curries and Worcestershire sauce.

I never actually saw a fresh tamarind pod until I went to Thailand. But during 20 years of gastronomic peregrinations, this tart fruit had crossed my path dozens of times.

I have sipped tamarindo sodas at sidewalk cafes in Sicily. I have spooned tamarind chutney over samosas (potato turnovers) in Boston’s Little Bombay. I have munched on tamarind candies from the Philippines at the Fruit & Spice Park in South Florida. I have gulped tamarind punch under a blazing sun at a juice bar in San Juan. I have even lounged in a hammock under the shade of an enormous tamarind tree, namesake and signpost of Le Tamarin restaurant in St. Barths.

As it turns out, I didn’t have to go so far afield to experience tamarind. The acidic fruit is a primary ingredient in a condiment found in every American kitchen: Worcestershire sauce.

Tamarind is a tall tropical tree with a fruity pod grown in Asia, India, Africa, the Caribbean and Latin America. The name comes from the Arabic tamr hindi : literally, Indian date. The Moors introduced tamarind to Spain and Portugal in the Middle Ages, and centuries later explorers brought it to the New World, where it was adopted with gusto.

The part of the tree we eat is the seed pod. Tamarind pods are shaped like fava bean pods, are three to four inches long and are covered with a hard brown skin with a light layer of fuzz. Each pod harbors eight to 10 black seeds. When the pod is ripe, the skin cracks open to reveal a thick, stringy, orange-brown pulp. This pulp is sharply acidic, like lime juice with an underlying fruity sweetness and a hint of smoke. Imagine a mixture of fresh lime juice and pureed prunes, and you will have an idea of tamarind’s taste.

Thanks to its fruity tartness, tamarind makes an excellent thirst quencher. (Tamarind soda and tamarind nectar are popular drinks in the Tropics.) In Thailand, the acidic pulp is used to perk up curries and stir-fries. Indians enjoy it in chutneys. Being both sour and fruity, tamarind makes an intriguing substitute for vinegar or lemon juice--in the parts of Lebanon and Syria where lemons won’t ripen, people may flavor their hummus or baba ghannouj with it. Several American chefs I know wouldn’t dream of preparing barbecue sauce without it.

That’s the good news. The bad news is that, in its natural state, tamarind is tricky (or at least messy) to work with. The first step is to turn the sticky, stringy flesh into “tamarind water,” also known as “tamarind puree.” If you use fresh pods, trim off the skin with a paring knife. Asian markets sell plastic-wrapped packages of peeled tamarind pulp. To make two cups tamarind water, you’ll need six to eight fresh pods or four ounces of peeled pulp.

Break the pulp into small pieces and place them in the bowl of a blender with 1 1/2 cups boiling water. Let this mixture stand for 15 to 20 minutes to soften the pulp. Run the blender in short bursts at low speed for 15 to 20 seconds to obtain a thick brown liquid. (Don’t blend too much: You don’t want to chop the seeds.) Pour this liquid through a fine-meshed strainer, pressing hard with a wooden spoon to extract the juices, scraping the bottom of the strainer with a spatula.

Return the pulp from the strainer to the blender and add 1/4 cup hot water. Blend again and pour the mixture though the strainer, pressing well to extract the juices. You should wind up with about two cups tamarind water. It will keep for one week in the refrigerator. I freeze it in ice cube trays to have two tablespoon portions of tamarind water whenever I need it.

If you live in an area with a large Latin population, you may be able to find frozen strained tamarind puree. The Cuban grocery store in my neighborhood sells it as pulpa de tamarindo. An eight-ounce bag costs $1.69.

This brings us to a third form of tamarind: a dark, thick, shiny syrup called tamarind extract. Made in India, this extract has the characteristic tartness, but lacks the pruney sweetness of fresh tamarind. You can make tamarind water of sorts from the extract, dissolving one tablespoon extract in four to six tablespoons water. To my taste, the extract is to fresh tamarind what a bouillon cube is to homemade stock. It’s convenient, however, and I’m not above using it in a pinch.

Tamarind is a traditional ingredient in Asian and African cooking. More recently, the sour pod has attracted the attention of progressive American chefs. Allen Susser of the Miami restaurant Chef Allen’s, for example, brushes tamarind glaze on roast rabbit and pine nut-encrusted fish.

To make the glaze, Susser simmers two cups fresh tamarind with three cups water, one cup white wine, 1/4 cup brown sugar, one teaspoon cumin and the juice of one lime. The mixture is boiled until two cups strained glaze remain.

To make a simple barbecue sauce, Susser blends equal parts molasses, mustard and tamarind water or tamarind glaze. Chris Schlesinger, co-author of the award-winning cookbook, “The Thrill of the Grill” (William Morrow: 1990), serves tangerine-tamarind sauce with West Indian-spiced grilled chicken. Mark Miltello of the restaurant Mark’s Place in North Miami features tamarind dipping sauce with spring rolls and tamarind banana salsa with fried oysters.

Nor is the mouth-puckering tamarind solely used for savory dishes and condiments. Children in the Caribbean and the Philippines nibble tamarind candies, made by rolling small balls of fresh tamarind pulp in granulated sugar. (Form 1/2-inch balls with your fingers, removing as many of the fibers as possible.) Tamarind butter--made by cooking down tamarind puree and sugar to form a spreadable paste--is delicious on biscuits and muffins.

In Indian or Asian recipes, tamarind pulp is often called for in balls. Pinch off the amount required and soak it in hot water ( 1/4 cup of water for every one-inch ball), as described above.

Fresh tamarind is in season from May to November. Look for it at Indian, Southeast Asian or Caribbean markets. Be sure the skin on the pods has started to crack open--a smooth unbroken skin indicates an unripe pod. Peeled tamarind pulp can be found at Asian markets, frozen tamarind puree at Hispanic markets.

In India and Southeast Asia, tamarind is believed to be beneficial to the kidneys and liver. In parts of Asia, the sour fruit is administered to fever victims like quinine. One tamarind pod contains about 5 calories, 20 grams of carbohydrates and 2 milligrams of potassium.

This summer refresher makes an unusual twist on commonplace lemonade.

TAMARIND NECTAR

6 fresh tamarind pods or 1/4 pound peeled pulp

2 cups hot water

4 to 5 cups cold water

1/3 cup sugar or to taste

Skin tamarind pods. Place pulp in bowl of blender along with hot water. Let stand 15 minutes. Blend in short bursts at low speed 20 seconds or until seeds are free of pulp.

Pour mixture through fine meshed strainer, pressing hard with wooden spoon to extract juices, scraping bottom of strainer with rubber spatula. Return seeds and pulp in strainer to blender and blend with 3 cups cold water and sugar. Strain mixture into tamarind puree. Cover and chill.

Just before serving, season nectar to taste, adding sugar if too sour or remaining cold water if too strong. Shake or stir well before serving. Makes 6 to 8 servings.