When a wine drinker thinks of Sonoma County, they likely focus on Pinot Noir. The top grapes by acreage are Chardonnay, Pinot Noir, and Cabernet Sauvignon, making up two-thirds of all the grapes grown in the county. There are smaller amounts of Zinfandel, Sauvignon Blanc, Merlot, and Syrah. The last ten percent is made up by over 50 other grape varieties. There's a move to diversify for several reasons.