“I was the type of guy who would break into your car and steal the change in your ashtray,” he said.

But it was not until several years after his last release from jail, in 2010, that addiction again took over and no one from his fractured family was there to catch him. He moved from one homeless encampment to the next until arriving earlier this year at his current spot by the 880 freeway and train tracks.

Mr. Holys loves talking about wine and laments that he has few people around him who share his passion. Over the relentless din of eight lanes of traffic and Amtrak and commuter trains rolling past his encampment in East Oakland, he evokes Opus, the Napa Valley cabernet blend, and Château Ducru-Beaucaillou, the left-bank Bordeaux. He smiles at the memory of sampling a 1974 Mondavi Reserve cabernet sauvignon.

But pinot noir is his favorite grape. “When it’s good and on point it’s an extraordinary experience,” he says, shirtless and in shorts on an unusually hot day last week.

Mr. Holys sees parallels between the cultivation of wine and his struggles. Pinot noir vines in particular are fragile and finicky, he says; the skins are thinner than other varieties and the best vines are stressed to produce better fruit.

“Roots are made to suffer. They have to strain for water,” he said. “It’s a metaphor for what people have to go through.”

Mr. Holys worked at restaurants where it was not uncommon to serve a $600 bottle of Puligny-Montrachet, the venerable Burgundy. If there was anything left in the bottle when the patrons left, he made sure to drip the remnants into his own glass.