Ever sipped a California Chardonnay, Cab-Sauv or Petite Sirah? Thanks to wine pioneers Wente and Concannon, we bet you have.

Take a close look, and it’s clear that the histories of the Concannon and Wente vineyards are as entwined as the vines in a block of old-growth Chardonnay. Both were founded in 1883—Wente by German immigrant C.H. Wente, Concannon by Irish émigré James Concannon—and both survived Prohibition to become among the oldest continuously operating wineries in the U.S. And finally, both have been instrumental to the success of California’s wine industry.

Wente got its start in 1912, when second-generation winemaker Ernest Wente convinced his father to import Chardonnay vine cuttings from France. In 1936, Wente became America’s first winery to bottle and label what is now the world’s most popular varietal. Those cuttings were eventually cultivated into the Wente clone of Chardonnay, the most widely planted in California. “Little did he know the impact he would make on today’s wine industry,” says current CEO Carolyn Wente of her great-grandfather.

Concannon tells a remarkably similar story. In the early 1970s, third-generation winemaker Jim Concannon collaborated with UC Davis to cultivate several Concannon Cabernet clones. Those same clones are currently the most widely planted in the state, playing a key role in achieving California Cabernet’s world-renowned status. In addition to providing the backbone for California’s Cabernet explosion, Concannon introduced Petite Sirah to America. So wine drinkers the world over have already tasted a piece of the Tri-Valley. Still, says fourth-generation vintner John Concannon, there’s nothing like going straight to the source. “If you want to understand a wine, the best thing is actually experiencing the terroir and vineyard it comes from,” he says, “to really see where the wine is born.”