Here's a late 20th century tale that Marcel Proust might appreciate: A young man, haunted by the taste of a simple, honey-flavored mustard his grandmother served in southern France, creates a Net business to make the delicacy available anywhere.

DJ (a.k.a. Didier Vallauri), a 34-year-old entrepreneur in Whippany, N.J., and his wife, Marcella, took $20,000 of their savings and in early December opened mustardstore.com, which they are billing as the "world's largest 'mustard only' store on the World Wide Web."

In fact, it seems to be the only site claiming such exclusivity, though other Net food sellers offer mustard. The niche-of-niches strategy hasn't drawn much business, yet. As of the afternoon of Dec. 7, mustardstore.com made three sales, for a total of about $30. Still, Vallauri is convinced that there's ample interest in the tangy sauce, which market research shows to be a favorite U.S. condiment. "I am hoping the site will become a mustard community, if you will," says Vallauri. "There are a lot people out there who are into this stuff. It is almost like an underworld."

Of course, Vallauri's not talking about the drippy yellow stuff on ballpark hot dogs. Want something spicy and hot? Mild with dill or garlic? How about fruit mustard from the Caribbean? It's all there. The site has a search engine that allows you to search by brand, manufacturer, or characteristics. Mustards range in price from around $4.55 for a Chinese brand called Kame to $13 for Pommery, a French brand. Vallauri says his site's appeal won't be low cost, or even for brands available in stores. Instead, it's variety.

Although Proust's masterpiece, Remembrance of Things Past, unfolds from the memories evoked by the taste of a madeleine -- a shell-shaped cookie -- dipped in tea, Vallauri's sensory revelation came from Savora, a French mustard that his grandmother served with rotisserie chicken. "I have always had a love for this specific mustard, and I could never find it here. But every time I would travel through Europe, I would bring it back," Vallauri says.

Vallauri was born in Queens, N.Y., of French parents. He got his nickname because kids thought his mother was saying "DJ" when she called for him. Beside his French heritage, little in Vallauri's background predestined him for a gourmet niche market. He went to work right after high school for airlines, bringing planes off ramps. Then, he jumped to the hospitality sector, where he learned about reservations technology.

HOT PROSPECTS. Today, Vallauri is vice-president of marketing and business development for Alphanet Hospitality Systems in Ramsey, N.J., which sets up mini-technology centers for corporate travelers in hotels. "I saw the Internet as an opportunity to apply the distribution and the electronic commerce background that I had with reservations technology to become a clearinghouse, if you will, for mustards," he says.

Can Vallauri keep faith with the virtual mustard community? He'll rely on agreements with the mustard manufacturers, many of which are tiny, family-owned concerns. Several have their own Web sites, but not online stores. That's where mustardstore.com comes in. Goods are generally shipped via United Parcel Service.

Mustard makers seem glad to have him, anyway. "We are a tiny, little business that concentrates on putting out good quality products," says Nancy Raye, president of JW Raye & Co. in Eastport, Me. Her family has made mustard for 100 years. "If he sold even $3,000 to $5,000 of our mustard in the first year, that would be incredible," she says.

Though Web businesses tend to be synonymous with rapid delivery, customers who have a burning need for a certain brand of hot, green Japanese mustard may have to wait: Vallauri says it can take up to two weeks to get a particular mustard delivered, because many suppliers are in remote places. Plus, reasons Vallauri, who'll pay for overnight shipping on a $10 jar of mustard?

At this point, Vallauri sells only 350 of the world's 2,000 mustard varieties. But, he says, it's only a matter of time before his company becomes the definitive mustard resource. "We will be continually adding new mustards," says Vallauri, whose site is targeting high-income people who are into gourmet food and cooking. Despite his unpromising first week, he expects $5 million in total sales in the next two years. How did he arrive at that figure? He cites a study by the market-research firm Find/SVP, which says 83% of U.S. households use mustard.

Chip M. Hearn, chief operating officer of Peppers Inc., a hot-sauce specialty store that has sold via the Web for the past three years, says he's lucky if his site pulls in $200,000 in sauce sales a year. "I don't know how the heck [Vallauri] could possibly do that, but more power to him if he can," Hearn says.

Vallauri, who's operating out of his house, offers an unProustian retort: "Mustard is a huge market." For all the entrepreneur's sentimental inspiration, he'll have to bank on that.

By Jeremy Quittner in New York
jeremy_quittner@businessweek.com