The first indication that the Luchsinger Vineyard might be noteworthy came when Duncan Arnot Meyers and Nathan Lee Roberts, the proprietors of Arnot-Roberts, decided they needed to make a trousseau wine. They already produced superb wines of balance and restraint, and, like many in the wine vanguard, they had developed a taste for the wines of the Jura in the last decade. The problem was, they couldn’t find any trousseau in California.

“We had called vineyards and nurseries all over the state,” Mr. Meyers said. “Finally, we just typed ‘trousseau’ into Google and worked backwards.”

The trail led them to the Luchsingers, who, though they grow the grape, had never tasted a trousseau wine. In 2001, Mr. Luchsinger had a brainstorm: imagining that California producers might want to try their hand at fortified wines, he would plant six acres with five of the grapes used to make port. Why not? The Douro Valley of Portugal, where port grapes are grown, is awfully hot, too.

Among the grapes he chose was bastardo, a lesser port grape that historically was used in Madeira, too, and that happened to be identical to the trousseau grape of the Jura. As Mr. Meyers and Mr. Roberts learned, the two acres he planted seemed to be the only vineyard block in California devoted to the grape.

Alas, the Luchsingers found that no producers were interested in making a port facsimile. While they managed to sell a few grapes here and there, the first real interest came when the Arnot-Roberts team arrived for the trousseau in 2009.