Mark Phillips's job is to teach others about wine. But last week, the executive director of the Wine Tasting Association got a wine lesson from a law enforcement agent that he won't soon forget.

Phillips, who lives in the Alexandria section of Fairfax County, heard that a fellow wine collector wanted to buy one of his bottles of 1991 Chateau Lafite Rothschild. The transaction seemed as mundane as the trading of a Beanie Baby or the sale of a baseball card, Phillips said. He said he didn't think twice about getting the bottle from his wine cellar and selling it for $110.

What Phillips didn't know was that the buyer was an undercover agent from the Virginia Department of Alcohol Beverage Control. Shortly after the purchase, ABC agents arrested Phillips on a charge of selling an alcoholic beverage without a license, a misdemeanor, and seized 12 other bottles of wine and several financial records from his home.

If convicted, Phillips faces up to a year in jail and a $2,500 fine.

Phillips doesn't deny that he sold the bottle of wine, adding that he has made similar sales in the past as a collector of fine wines. He said he simply didn't know that selling wine from his 200-bottle private collection was against the law. The Wine Tasting Association, a nonprofit group that hosts wine tastings throughout the Washington area, has had no part in any wine sales, he said.

"It was news to me that that was illegal," Phillips said yesterday. "Anyone knows that people who are into the wine business, they buy wine. From their private stock, they'll sell to someone, like a collector sells any other valuable item. People do it all the time."

ABC officials said that it is rare for them to arrest anyone for selling wine in a home and that it is usually businesses that are caught violating the law against selling alcohol without a license.

"In the last year, I don't believe we've made any other arrest that compares in style to the arrest involving Mr. Phillips," said Phillip G. Disharoon, a spokesman for the ABC regional office in Alexandria. But, he added, "the violation is ultimately the same. . . . For the most part, in order to sell alcoholic beverages in Virginia, you must hold an ABC license."

Disharoon said agents began investigating Phillips in June after they discovered that his association's Web site offered bottles of wine for sale. Phillips acknowledged that such an offer "may have existed on the Web site." It was no longer posted there as of yesterday.

Disharoon said yesterday that Phillips has obtained seven one-day ABC licenses since July 1997 for wine tastings or related events. But Disharoon said there is no license in Virginia that would allow an individual to sell alcohol from his or her home.

Suzanne Horsley, a spokeswoman for ABC headquarters in Richmond, said the agents' visit to the Web site was not part of a crackdown on Internet alcohol sales, though she said that ABC agents have been grappling with that issue as well. Anyone selling alcoholic beverages to Virginia residents over the Internet must have a Virginia ABC license, and the product must be shipped to an approved Virginia distributor.