ARLINGTON, Va. -- At a party here one recent Friday, Jacob Grier stood on a chair, pulled out a plastic bag full of small berries, and invited everyone to eat one apiece. "Make sure it coats your tongue," he said.
Mr. Grier's guests were about to go under the influence of miracle fruit, a slightly tart West African berry with a strange property: For about an hour after you eat it, everything sour tastes sweet.
Within minutes of consuming the berries, guests were devouring lime wedges as if they were candy. Straight lemon juice went down like lemonade, and goat cheese tasted as if it was "covered in powdered sugar," said one astonished partygoer. A rich stout beer seemed "like a milkshake," said another.
After languishing in obscurity since the 1970s, miracle fruit, or Synsepalum dulcificum, is enjoying a small renaissance. In-the-know food lovers from Hawaii to Finland are seeking out the berry as a culinary curiosity. In Japan, it's freeze-dried and canned or sold in tablets. Some restaurants there have featured it as an avant-garde dessert, including at Tokyo's Mandarin Oriental hotel. So has the Four Seasons Resort in Palm Beach, Fla., where two miracle-fruit shrubs are planted in the hotel's garden.
Growers like Curtis Mozie of Fort Lauderdale, Fla., are racing to keep up with the recent demand. The 63-year-old retired postman has cultivated the slow-growing shrub for a decade, and now says he has hundreds of them at a nursery near his home.
Most of the small number of U.S. growers sell cuttings or seeds for chefs or other aficionados to grow their own plants, rather than shipping the highly perishable berries. After a food lovers' blog called EatFoo, to which Mr. Grier contributes, began spreading word in February about Mr. Mozie's product, he raised his prices to $1.80 from $1 per fruit. He ships them overnight, because the red berry -- about the size of a grape with a large pit -- turns brown and unappetizing within a day or so after it's picked.
Scientists say a protein in the fruit works by binding to taste buds and altering the tongue's so-called sweet receptors to activate when sour foods are eaten. A French explorer known as the Chevalier des Marchais first encountered the effects in 1725 somewhere in West Africa, says Adam Gollner, who is writing a book about miracle fruit. The chevalier saw villagers eat the berry before consuming gruel and palm wine, so he gave it a try himself.
In 1852, a British surgeon described the fruit in a pharmaceutical journal as a "miraculous" berry. In the early 20th century, a renowned botanist for the U.S. Department of Agriculture, David Fairchild, was the first person to bring miracle fruit from Africa to the U.S., says Linda Bartoshuk, a professor at the Center for Smell and Taste at the University of Florida.
Lloyd Beidler, a biology professor at Florida State University, and a colleague isolated the active protein in the berry in 1968, which Dutch researchers doing similar work dubbed "miraculin." Around the same time, Ms. Bartoshuk was doing research on the berry for the U.S. Army, which never went as far as adding it to rations. She remembers eating a bologna sandwich with mustard at the laboratory's cafeteria during the testing. It tasted "like a sweet."
Because miracle fruit is so delicate, scientists for years have tried to genetically engineer other organisms to produce miraculin. This led to a series of failures. In the 1990s, researchers tried unsuccessfully to alter tobacco plants, yeasts and even E. coli bacteria to produce the same protein, which is one of seven known to have a sweetening effect, but the only one that turns sour to sweet.
Last year, a team of scientists led by Hiroshi Ezura, a professor at Tsukuba University near Tokyo, said they finally succeeded -- with lettuce. In a scientific report published in Federation of European Biochemical Societies Letters, the researchers wrote that two grams produce roughly the same effect as one miracle fruit.
Mr. Ezura, who is collaborating with Inplanta Innovations Inc., a Japanese biotech company, says his team next hopes to develop a genetically modified tomato, possibly for commercial use as a low-calorie sweetener or as an additive for foods targeting diabetics, since it removes the need for sugar.
Several miracle-fruit growers in Florida also say cancer patients occasionally seek out the fruit because it reportedly alleviates a metallic taste in the mouth that is one side-effect of chemotherapy. There is no scientific research supporting the claim.
Miracle fruit remains in a kind of regulatory limbo in the U.S. It's perfectly fine to grow and sell it, because the Food and Drug Administration doesn't require prior approval to sell fresh fruits, though it can intercede if it suspects problems. The trickier part comes when people try to use it as an additive in other foods. That's when regulators start asking questions.
Two American entrepreneurs, Robert Harvey and Don Emery, tried this route back in the 1970s but the venture ended in heartbreak. Their initial focus was on products for diabetics, but some of their financial backers, which included Reynolds Metals Co. and Barclays Bank PLC, had a loftier goal. "They were interested in replacing half the sugar industry in the world," Mr. Harvey says.
Mr. Harvey figured out how to turn miracle fruit into a dried powder and then a tablet. His company, Miralin Co., explored making everything from chewing gum to a miraculin-coated drinking straw. It developed recipes for diabetics which assumed people would pop a miracle-fruit tablet before eating the results.
Reynolds, now part of Alcoa, then owned the Eskimo Pie brand of frozen snacks and suggested trying miraculin-coated ice pops. In the summer of 1974, a group of Harvard Business School students conducted ice-pop taste tests on Boston playgrounds, giving children a choice between regular ice pops and miraculin-coated ones. The children preferred the latter by a wide margin, Mr. Harvey says.
That same year brought a big setback: The FDA sent a letter calling miraculin a "food additive" requiring years of testing. The letter effectively scuttled the venture, which was on the verge of selling products and wasn't prepared to spend money on extensive testing. Miralin filed for bankruptcy and fired 280 employees. It's only in the past five years that "I'm able about to laugh about this instead of crying," says Mr. Harvey, now 75 years old, who went on to a lucrative career making blood pumps used in heart surgery.
The berry has lured other entrepreneurs. A few years ago Kodzo Gbewonyo, a biochemist in New Jersey, took early retirement from drug maker Merck & Co. to develop miracle fruit and other native West African plants.
Mr. Gbewonyo fondly recalls eating the berry as a boy growing up in Ghana. He says he sometimes uses the berry to add sweetness -- he calls it "body and smoothness" -- to a glass of cabernet. His company received a patent in 1999 for a method of purifying miraculin and is exploring whether the extract can be approved in the U.S. as a dietary supplement.
At the Arlington party hosted by Mr. Grier, a barista at a Georgetown bakery and coffeehouse, guests milled around a table covered with a wide assortment of tart and sour foods -- lemons, limes, grapefruits, pomelos, rhubarb, dill pickles, cheeses and sour candy.
"Rhubarb is the big winner, it's like a sugar stick," said Lalitha Chandrasekhar, a 22-year-old researcher at the National Institutes of Health.
Paul Sherman, 27, who works at a nonprofit group that studies campaign finance, followed his miracle fruit with strawberries and found them "like strawberry-flavored candy ... almost too sweet." It was, he concluded, "the strangest gustatory experience I have ever had in my life."