NAPA, Calif. — How do you make a small fortune in the wine business? Start out with a big one.

Yes, it’s an old joke, but that does not diminish its essential truth. To live the mythical good life as a wine producer is excruciatingly difficult, unless you start out with a lot of money, inherited vineyards or both. Particularly in California. Especially in Napa Valley.

Even so, a number of young, intrepid winemakers are demonstrating that it can be done, by working around the edges, going where few have gone before and putting in plenty of sweat equity . Some are making great wines, too.

John Lockwood of Enfield Wine Company is one of those dedicated few, finding ways to make a small amount of captivating wine in the Napa Valley area without much money and with no vineyard holdings. While many winemakers in similar positions work day jobs to support their own labels as side projects, Mr. Lockwood, 38, has gone all-in at Enfield.

He is based here in the city of Napa, but few of his wines are entitled to the Napa Valley appellation. Until recently, Mr. Lockwood never made a Napa Valley cabernet sauvignon, the wine for which Napa is most famous. He could not afford to buy the grapes, which he said sold last year for an average of $7,500 a ton.