WHEN Eileen Judge, a 27-year-old tempeh maker, introduces her product to people, she keeps the story simple, sticking to recipes with familiar titles like tempeh barbecue.

It's easy to see why. Tempeh is made from soybeans that are hulled, cooked, cooled and inoculated with a culture (just as milk would be for cheese), and left to incubate for 24 hours. The mold growth "weaves the beans together," says Judge, who makes tempeh in a Morse Street warehouse and distributes it to about 20 area health food stores and co-ops. This results in a very firm, solid loaf that can be sliced and cooked in a variety of ways.

Not a description to woo potential fans.

Strange as it sounds, it plays in Peoria. Researchers there at the U.S. Department of Agriculture's research laboratory are enthusiastic about tempeh. Dr. Clifford Hesseltine, who has spent 20 years researching tempeh production, says whenever they make up a batch of tempeh, "it gets eaten up right away." The only person he's known to not like it was his daughter, who wouldn't taste it.

Had she, she would have found that tempeh isn't bland like its soy cousin, tofu. It has a distinctive, musty flavor. Hesseltine compares it to almonds. Tempeh is to tofu what blue cheese is to cream cheese.

"After eating tempeh for such a long time," says Judge, "tofu is pretty boring stuff."

And unlike tofu, which now stocks the shelves of even the most mainstream metropolitan supermarkets, tempeh is relatively unknown, says Judge, even to the thousands of vegetarians in the Washington area. While bland, versatile tofu can become anything from dinner to dessert, tempeh's distinctive personality relegates it to "meatier" dishes. Even those people know of it tend to relegate it to "croutons"--toasted tempeh topping for salads and sauces.

Like tofu, tempeh has Blue Book nutrition status. Tempeh is a reliable plant source of vitamin B-12, containing about 140 percent of the recommended daily allowance. "That's really important for vegetarians who don't eat any animal products," says Judge. Soybeans, always known for their high quality protein, also contribute significant amounts of iron, vitamin B6, phosphorus and riboflavin (vitamin B2) to the diet and small amounts of other vitamins and minerals. But soybeans contain all of their original fat, which makes them more caloric than the soybean derivative tofu.

Fermentation distinguishes tempeh from other beans and soy products. It enhances their digestibility (reducing gas) and gives it a distinctive taste. The mold also produces a low-grade antibiotic, according to Hesseltine. "Not strong enough" to be used as a drug, he says, but strong enough to have a "beneficial effect" on the population of Indonesia--virtually the only one for which tempeh is a staple.

Judge believes that the soybean "explosion" is coming. Even tofu, which "gets a lot of press," hasn't made the impression that it, along with tempeh and miso (another fermented product), will make, she predicts. Hesseltine thinks that someone needs to package tempeh culture, the way yeast is packaged for bread bakers. Tempeh "is easier to make than bread," he says, as long as you have a strong culture to begin with.

In the meantime, says Judge, people are becoming more accustomed to soybeans. Once only animal food, they now go into unsaturated vegetable oils, margarines, emulsifiers, flours and a whole host of modified meat products. Now that they're seeing soy in their hamburger, Judge says, people are getting more experimental.

And "people concerned about their health are getting more courageous. People don't have a choice any more because of their health," she says, adding, ". . . anybody with brains in their head is getting away from meat."

Still, deciding what's good for you is one thing, and altering your diet is another. Not everyone could bear the thought of buying a lump of moldy soybeans, although the same people may have no problems relishing a hunk of Roquefort cheese.

To encourage familiarity, Judge cooks "things that remind me about all the things I've had"--gravy and spicy tomato sauce, pa te' and salad and dip. She says she would make chili if it didn't take so much time.

Those inclined to experiment can pick up a little tempeh at their neighborhood co-op or health food store and try some recipes in the new style or the old. BARBECUED STRIPS (4 to 5 servings) 8 ounces tempeh, cut into 1/2-by- 1/4-inch strips 4 tablespoons oil 2 stalks celery, chopped 1 large onion, chopped 2 cloves garlic, crushed 3 tablespoons soy sauce 1 tablespoon molasses 2 tablespoons honey 6 tablespoons ketchup 3 to 4 tablespoons red wine or cider vinegar 1/4 to 1/2 teaspoon dry mustard Pinch hot Hungarian paprika Salt and pepper to taste Juice of small orange

Heat oil in large skillet. Fry tempeh strips until dark brown on both sides. Remove and drain on paper towels. Saute onions, celery and garlic in remaining oil for 3 minutes. Add remaining ingredients, except tempeh, and simmer for 5 minutes. Finally add the tempeh and cook on low heat for 10 to 15 minutes. Serve hot on buns or over rice. TEMPEH PATE (About 2 cups) 2 tablespoons vegetable oil 1 cup of slivered almonds 2 tablespoons butter 1 small onion, minced 1/2 pound sliced mushrooms 1 clove garlic, minced 1 jalapeno pepper, seeded and minced 8 ounces tempeh 1/2 teaspoon salt 1/4 teaspoon thyme 1/8 teaspoon leaf sage 1 tablespoon tamari

Toast the almonds in a 325-degree oven for about 15 or 20 minutes until they are golden brown. Set aside to cool. Saute' the onion, garlic, jalapeno and sliced mushrooms in butter until mushrooms are soft and most of the liquid has evaporated. Meanwhile, cut the tempeh in quarters and steam for about 10 minutes. Remove the tempeh from the steamer and cube it before adding to mushrooms. Stir in salt, thyme, sage and tamari. Cook, stirring often, until the mixture is almost dry, about 5 minutes. In a food processor or blender, grind the toasted almonds very fine then add the oil. Continue processing until a thick nut butter forms. Add the tempeh mixture and process until it is thick and smooth. Taste and adjust for seasonings and serve chilled with crackers. TEMPEH STIR--FRY (6 servings) 3/4 cup water or vegetable broth 1/3 cup tamari 1 tablespoon grated ginger 2 or 3 cloves garlic, minced 2 teaspoons sesame oil 2 tablespoons cornstarch 1/4 teaspoon red pepper flakes 2 tablespoons vegetable oil 1 bunch scallions (including tops), sliced 3 carrots, cleaned and sliced 8 ounces tempeh, cut in small cubes 1 head broccoli, cut into florets 8 ounces mushrooms, sliced if large 2 tablespoons sesame seeds 6 cups cooked rice

Combine broth, tamari, grated ginger, garlic, sesame oil, cornstarch and red pepper. Stir to blend and set aside. Heat vegetable oil in wok, tipping the wok to coat the bottom. When the oil is hot, add scallions and stir for 1 minute. Add carrots, tempeh, broccoli and 2 tablespoons of water. Cover the wok and steam about 4 minutes, stirring occasionally. Add mushrooms and stir 2 minutes longer. Add sesame seeds and stir 1 minute more. Add sauce and stir over flame until the vegetables are coated and the sauce is transparent. Serve with rice.