The SOMM Journal

October / November 2016

Issue link:

Contents of this Issue


Page 26 of 132

26 { THE SOMM JOURNAL } OCTOBER/NOVEMBER Winemaker Kevin Sass of Halter Ranch is a de facto expert on red blotch. { getting geeky } KEVIN SASS, WINEMAKER AT WELL-KNOWN Paso Robles winery Halter Ranch and a hands-on expert on red blotch virus, led me through an informative PowerPoint presentation on the vine disease, which he says is a concern in Paso and elsewhere. Then we tasted a Cabernet Sauvignon from a vineyard block infected with red blotch virus alongside one from a block without the virus to see whether we could isolate the difference in mouthfeel—the variance was blatant. Looking at the two wines side by side, the contrast in color also indicated less-ripe fruit and lighter concentration in the red blotch affected wine. Red blotch virus—scientifically referred to as grapevine red blotch asso- ciated virus (GRBaV)—inhibits the production of sugar once the grapes reach 19–21.5° Brix. Sugar and anthocyanins (color, pigments and flavors that come from skins) are directly related; without an increase in sugar levels, the anthocyanins do not reach full potential. Lower anthocyanins translate to a thinner mouthfeel. Anthocyanin molecules bind with tannin molecules, creating bound anthocyanins. "Phenolics is really just a measurement like alcohol or total acidity," states Sass. In order to learn more about red blotch and its effect, he utilized a version of the Harbertson-Adams Assay to measure anthocyanins, tannins and anthocyanins bound to tannins. The key to understanding the depth of the influence of red blotch is in understanding bound anthocyanins. According to Sass, "They are the soul of the wine. They create mouthfeel, richness and weight." Anthocyanins are water-soluble while tannins are alcohol-soluble; this is the reason behind cold soaking: You can extract color without extracting tannin. "With anthocyanins, you reach a color peak; there is a finite level of color. The key is to reach that peak well before the tannin levels get too high. That's the winemaker's job," explains Sass. By cold soaking and closely monitoring fermentation, adjusting temperature and the frequency of pump-overs, Sass achieves tannin levels about 15 percent higher than anthocyanin levels, in order to be certain every color molecule has a tannin partner with which to bind. To illustrate the point, we discuss the northern Rhône's practice of co-fermenting Syrah with Viognier. Viognier has a high tannin content, which allows more anthocyanins to bind, increasing both color and weight. "Grape tannins do not diminish over time. Neither does bound anthocyanin." The idea is to get these levels congruent with one another, and suddenly you have a wine—with extraction, persistent but balanced tannins and a richness on the palate—that can age far longer. As for moving forward, Sass reveals, "We've been through many, many trials to try to alleviate this stall that Red Blotch causes, and nothing works. So we're in replant mode; we only have a few remaining blocks. Our wines have been solid, but they are going to continue to get better now. We're excited to see the full capacity of our potential." Saving the "Soul of the Wine" GRASPING THE RED BLOTCH VIRUS WITH THE HELP OF HALTER RANCH by Allyson Gorsuch higher extraction, can age many works. T A N N I N A N T H O C Y A N I N T A N N I N A N TH O C Y A N I N PHOTO: JEREMY BALL ILLUSTRATION: TOM DONCHEZ

Articles in this issue

Archives of this issue

view archives of The SOMM Journal - October / November 2016