During the early 1970s, Dexter and Valerie Ahlgren began to dabble in fermentation at their suburban home in the town of Sunnyvale. They experimented with beer, mead, and Zinfandel grapes. The results were impressive, and the couple began to ponder a career in winemaking. At the time, Dexter was a civil engineer and Valerie taught at De Anza Community College.
In 1973, the Ahlgrens decided to build a house in the Santa Cruz Mountains and pursue their dream. They also built a small cellar and winery in the hillside underneath their home. In 1976, Ahlgren Winery was bonded and the first vintage was produced. To this day, the wine is still made in the cellar under their house.
Their estate wines include Cabernet Franc, Merlot, and Cabernet Sauvignon. Wines they make with purchased fruit include Chardonnay, Zinfandel, Semillon, Pinot Noir, and Syrah. The Ahlgrens also make a red wine called Tre Vini-Rossi. This is a blend of Nebbiolo, Cabernet Franc, and Cabernet Sauvignon.