San Antonio’s Lara Vineyard is fermenting more than just grape juice.

The upstart vintner has incurred the wrath of California’s San Antonio Winery, which has filed a trademark-infringement lawsuit over the Alamo City vineyard using “San Antonio” in the name of some of its wines.

“I’ve lost a lot of sleep over this,” conceded Lara Vineyard owner Michael Lara.

In July, the federal Alcohol and Tobacco Tax and Trade Bureau approved the labels for Lara Vineyard’s Blanco Dulce de San Antonio and Blanco de San Antonio, the fanciful names for two of the vineyard’s white table wines.

Two weeks after the approvals, San Antonio Winery’s lawyer sent a letter to Lara Vineyard directing it to modify those labels to exclude “San Antonio” from the wine names as part of a trademark dispute.

“It is to neither party’s benefit to have confusion in the marketplace,” San Antonio Winery lawyer Jeffrey Sheldon warned. “Just as you would protect Lara as a trademark, San Antonio Winery must protect its ‘San Antonio’ mark.”

Lara said he responded by saying, “I’ll go ahead and change anywhere it says ‘San Antonio.’ I’ll make sure it’s San Antonio comma Texas. All of my labels will read that.”

Lara said he altered the vineyard’s home page on the Internet to drop “San Antonio” from one reference and to add “Texas” in another. He also modified the labels to try to avoid any confusion with the California winery. They now read: “Blanco Dulce de San Antonio, Texas” and “Blanco de San Antonio, Texas.”

The changes Lara made didn’t resolve the issue for San Antonio Winery, which filed its federal lawsuit on Tuesday in the U.S. District Court in San Antonio.

San Antonio Winery “has no objection to Lara Vineyard using the term ‘San Antonio’ solely as a geographic indicator for the source of the wine,” Sheldon said in an interview, reading directly from the lawsuit. But San Antonio Winery objects to the mention of San Antonio in the official name on the label.

“It’s a trademark use — we object to it,” said Sheldon of Pasadena, California.

Ted Lee, who represents Lara Vineyard, said he is preparing a motion to have the lawsuit tossed.

“If (a product) indicates geographic origin, then it’s proper and fair use,” Lee said. “It is not infringing anybody, whether or not they have a trademark.”

He added, “If you’re from San Antonio, do you think you’re entitled to tell people you’re from San Antonio?”

Just like the city, San Antonio Winery takes its name from St. Anthony of Padova, a popular saint of the Catholic Church.

San Antonio Winery founders, who launched the business in 1917, were very religious, Sheldon said.

“Their main product in that time was sacramental wine, and so they named the winery San Antonio,” he said. It has used the trademark “San Antonio” since 1933.

Today, San Antonio Winery’s brands include San Antonio California Champagne, San Antonio Specialty and Stella Rosa. The Los Angeles-based winery operates various vineyards in California.

Lara operates his vineyard on a few acres by his home on the far North Side. He planted vines about five years ago and recently started selling wine, he said. The vineyard received various label approvals from the Texas Alcoholic Beverage Commission in August, the agency’s website shows. It is authorized to sell wine only in Texas, Lee said.