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WINEMAKING creases wine scores directly, it also leads to finer, softer tannins and prolongs age- ability.1 The strategy worked, producing wines that sensory analysis was able to significantly differentiate. In 2006, Wample got funding for a larger project, this time looking at Cab- ernet Sauvignon. At Constellation Wines' Twin Creeks Vineyard in Lodi, 35 acres were measured for anthocyanin, Brix and berry weights on a grid at 10 samples per acre, both in late August and again in early September. When metrics were mapped by GPS, variation across the field was again appar- ent. Differential harvesting of 40-ton lots resulted in 30% increases in both total phenols and anthocyanins, and a 14-mem- ber panel significantly preferred the high anthocyanin lot. While significant differences between the lots were promising, no easy causal pattern was apparent. Not only did Brix fail to match up with anthocyanin, but maps of normalized differential vegetation index (based on chlorophyll reflectivity) were completely unrelated. Wample had found a useful harvest tool but no under- lying causality that growers could use to make improvements. Ranch-WV-080211.pdf Enter the draggin' Wample had so far failed to find anything suggesting an easily measureable parameter that could cheaply assess where the good stuff might be found without resorting to the expense and tedium of mapping berry com- position. If he found the underlying sources of variability, he might be able to go a step further, enabling the grower to improve problem areas and increase uniformity. Soil drivers are a fundamental breakthrough in winegrowing. Wample went looking for this Holy 1 8/3/11 3:56 PM Grail in an area California viticulturists have long pooh-poohed: soil variability. As late as the 1980s, New World viticultur- ists at the University of California, Davis, and in Australia were still in denial about the European concept of terroir, scoffing at any direct connection between soil com- position and grape composition. While technically correct, this hard-liner position diverted academic attention from the criti- cal influence of soil on flavor expression. Store it at The Ranch. C M Y CM MY CY CMY K NO IN-FEES IF DELIVERED BY SEPT. 1 FOR 25,000 & 50,000 GAL. TANKS. CRUSH | WINEMAKING | BARREL & BULK STORAGE | BOTTLING 707.963.4520 RANCHWINERY.COM SAINT HELENA, CA, NAPA VALLEY Wines & Vines sePTeMBeR 2011 57 But in 2001, famed down-under grape guru Richard Smart finally pronounced, "I give up. I was wrong. Terroir differences really do exist." Practical application is another story. Vineyards are generally laid out in blocks according to property lines and tilling con- venience. Since wire trellises favor linear layouts, soil variability is almost never considered or even known. The prospects for guiding viticultural practices according to soil variability im- proved considerably in 2007, when STI launched their Soil Information System (SIS), previously reported by Cliff Ohm- art.2 Thanks to a fleet of towed detection toys including a conductivity sled "surfer" and a penetrometer drilling "diver" with moisture, resistivity and color sensors and soil core sampling capability, 65 data di- mensions can be collected, then digested by sophisticated fuzzy logic software, rendering the complex data set into three- dimensional vineyard maps. Due to a request from Constellation in 2007, Wample's project shifted to the Mer- jan Vineyard,3 80 acres of Cab Sauv planted in Madera, Calif., at a mechanically pruned, drip-irrigated vineyard on a variable mix of sand and clay that STI had mapped.