When Mark Herold and his wife Erika Gottl climb out of bed in the morning, they carry their coffee cups from the kitchen of their modest wood- frame house on a working-class residential street near downtown Napa to a bonded winery -- their garage.

To a casual observer, that tin-roof structure seems suited to shelter a couple of dusty pickup trucks, maybe a lawnmower. To Herold and Gottl, it's the home of Merus Wines, where they produce less than 500 cases a year of one of the most sumptuous, coveted Cabernet Sauvignons in the country. Wine critic Robert M. Parker Jr. tasted it a few years back and fell madly in love. ***

Garagistes share a passion in their approach to winemaking that often trumps profit. Marketing and sales usually take the form of a basic Web site, a mailing list, local restaurants and possibly a few small distributors. Gottl parcels out Merus three bottles at a time to devoted customers willing to pay $105 a bottle. But most garagiste efforts retail between $20 and $50.