Good Fruit Grower

August 2012

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Do low yields make better wines? Gallo's Nick Dokoozlian says there's more to making good wines than low tonnage. by Melissa Hansen merica's wine industry has a split personality. Growers and winemakers use New World meth- ods, like irrigation and modern winemaking techniques, but much of the Old World men- tality has been retained, says the head viticul- turist for E. & J. Gallo Winery. But until better yield and wine qualitative metrics are developed, changing century-old traditions will be difficult. Years ago, the idea that lower grape yields always make better wines, a European perspective brought to Amer- ica, wasn't that far off, said Dr. Nick Dokoozlian, vice pres- ident of viticulture, chemistry, and enology for E. & J. Gallo of Modesto, California. Early wine-grape vineyards in California were unirrigated and planted to wide spac- ings (8 by 12 feet) with noncertified plant material under a hodgepodge of soil and vineyard conditions. However, today's vineyards feature high-density spac- ings of six by eight feet or closer, drip irrigation, virus-free planting stock, and canopy management to keep vines in balance, a term used to describe vines that have adequate leaf area to ripen and mature the crop load. While strides have been made in modernizing plantings, Dokoozlian said research in the wine industry is still lacking and has not kept pace with technologies in other commodities. "Our industry hasn't advanced much compared to others," Dokoozlian said, noting that winemaking tech- niques have moved from wood to stainless steel tanks, but most other things are still the same. In contrast, table grape and raisin growers in California have doubled yield and quality in the last two decades by applying advanced technology, said Dokoozlian, who before joining Gallo spent 15 years with the University of California's viticulture and enology department, working with the state's table, raisin, and wine grape industries. "But we've not done that in wine grapes." The problem as Dokoozlian sees it is that the New World wine industry in the United States has retained Old World mentality. "From a research platform, we've failed to take into consideration all these things that we've changed from a production system and how they allow us to really unleash the power of new technology to change this traditional view of yield and quality," he said during a session at the annual meeting of the Washington Association of Wine Grape Growers. Yield-quality research At Gallo, Dokoozlian is focused on a wide area of research for grape and wine production, including devel- opment of growing practices that improve yield and qual- ity of grapes and wines and development of grape and wine chemical quality metrics. In looking at the yield ver- sus quality question, he has studied a variety of quality aspects at different crop loads, from color and sugar to positive and negative aromas (beta-damascenone and methoxypryrazine), odor and mouth feel intensity and activity. He's also looked at canopy and trellis systems and their effects on leaf exposure and photosynthesis. In short, there's no easy answer to the yield versus quality question. Low yields do not make higher quality wine, but there's more going on in a vineyard than just yield, he says. For example, in tracking the grape antho- cyanin levels at different yields in hundreds of vineyards in California's Lodi area, he found high anthocyanin levels in both high- and low-yielding vineyards. Pruning weight to leaf area ratios (also called yield to pruning weight ratios) are used to determine if vines have enough canopy to ripen the fruit. This concept of a bal- anced vine, a measure of the pruning weight divided by leaf area, has been used by the industry for more than 25 years, Dokoozlian said. Optimum values have been developed for vines in balance: a ratio of 5 to 8 is in bal- ance; a ratio of 4 or less is undercropped; and more than "Our industry hasn't advanced much compared to others." —Nick Dokoozlian 10 is considered overcropped. Dokoozlian uses vine bal- ance in his research instead of tons per acre because it accounts for differences in vineyard design, plant density, vine vigor, and site capacity. Odor and mouth feel In Dokoozlian's research looking at undercropped, balanced, and overcropped Cabernet Sauvignon, the undercropped vines (yield to pruning weight ratio of 3 and equivalent to 2 tons per acre) reached 24° Brix two weeks before the balanced vines (7 tons per acre, yield to pruning weight ratio of 8), while the overcropped vines (12 tons per acre, yield to pruning weight ratio 14) hit that sugar level two weeks later than the balanced vines. 52 AUGUST 2012 GOOD FRUIT GROWER www.goodfruit.com

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