Issue link: http://winesandvines.uberflip.com/i/101495
GRAPEGROWING to have no difficulty identifying the vineyard plots that produced their best wines. So there you have it: no point system, no fancy quantitative methods. I just accept what they tell me about their wines (with a small amount of tasting by myself to keep it honest.) An award-winning wine, of course, has to be mentioned, and I do so with no apology. Shifflett Estate Vineyards Shifflett Estate Vineyards Graphics: JBA Works INC. CAD: T. Zitko A geologic map of Shifflett Estate Vineyards covers the area where five Bordeaux varieties grow. Darms Lane Vineyard Graphics: JBA Works INC. CAD: T. Zitko Fourteen acres are planted at the Darms Lane Vineyard pictured in this geologic map. Jeffrey Shifflett produces all five red Bordeaux grape varieties on 60 planted acres, but most of the production is Cabernet Sauvignon and Merlot. He definitively singles out three vineyard blocks. His best is F block: high on a hill, which is planted with Cabernet Sauvignon Selection 7 on St. George rootstock (he says this is unusual.) It produces a ���killer��� wine that has done well for him since 1998. No doubt climatological conditions and the right vines matched to the right soil are important, but it is remarkable how well the block location corresponds to a dominant dacite unit lithology. The dacite consists mostly of fine-grained volcanic flows. Chemically, dacite has a fairly high silica (SiO2) content. The soil is thin on F block, and the underlying rock breaks into small chunks. Drainage is naturally good. Nature has provided for Shifflett in multiple ways on this small hill. The winegrower often ends his tastings by hauling customers up the hill in the bed of his rickety pickup truck to see the great view. This informal, almost counter-culture Napa experience sets Shifflett apart and makes for an appealing and memorable visit. I saw him bring a lot of happy people up the hill while I was mapping in the field, and it brought home the fact that wine is about more than a drink. Second best for Shifflett is block B1, a Cabernet Sauvignon Selection 6 (the Jackson clone) on 110R rootstock. This excellent block resides on a rock unit of andesite-dacite and soil derived from it and transported just downhill. This rock that spans the compositional fields of both andesite and dacite (see examples on page 92) has less silica than the dacite of block F, but it is also a volcanic flow rock. A distinctive rock, it can be characterized as containing abundant, larger feldspar crystals (18%-27%) set in a medium to dark gray and even blackish matrix that is very fine grained and sometimes glassy. This is one of the dominant rock types of the hillsides west of Napa Valley, exWin es & Vin es JA N UA RY 20 13 89