The Trefethen wine cellar encompasses 13,000 square feet at this award-winning winery and serves as a storage site for barrels during the aging process. While the original historic building of Trefethen Napa Valley is still in use for the Estate Tasting Room and is home to the wine library, a new state-of-the-art facility has also been added. Like many Napa Valley wine cellars, the perfect conditions have been discovered for aging wine, and Trefethen makes the most of them. Nine grape varieties (Chardonnay, Merlot, Cabernet Sauvignon, Pinot Noir, Riesling, Cabernet Franc, Viognier, Petit Verdot, and Malbec) contribute to the wines made by Trefethen Napa Valley.

Of all the Napa Valley wine cellars, Trefethen is glad to say that they have never purchased any outside grapes. All of the wine in the Trefethen wine cellar was grown on their own land, using sustainable practices. Located at the cooler, southern end of Napa Valley, the winery has a long history. A tour of the historic winery will bring visitors to the wine cellar and conclude with a tasting of Trefethen's delicious creations. For guests who are just interested in the wines, no reservations are necessary, and tastings are available daily from 10 am to 4:30 pm.