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WINEMAKING Palate Structure and Texture Balance Components Volume, Body, Sweetness <——> cid + Phenolics (tannin intensity, A astringency, dry tannins, bitterness) Volume, Body, Sweetness • Carbohydrates • Polysaccharides • Mannoproteins • Gums • Alcohol Acid • Organic acids intervals. For example, we initially taste sweetness at the front of the palate, followed by acidity, and finally the taste of bitterness and tactile sensation of astringency near the back of the palate. Yet we expect in a high-quality, well-integrated and balanced Viognier not to perceive these as separate sensations, but as a harmonious whole. Palate balance is impacted by the quantitative and qualitative nature of components in the above relationship and wine temperature. For example, a low temperature can increase the perception of acidity while reducing the perception of sweet elements. Warming wine a few degrees often reverses this by increasing the Phenolics • kin, seed and stem phenols S • Barrel phenols • Enological tannins • Volatile phenols sweet perception, thus lowering the sense of acidity and the discernment of phenols. This highlights the inverse nature of the palate-balance relationship. It also serves as a reminder of the importance of specific serving temperature recommendations predicated on style and essential for optimum wine enjoyment. The relative interaction of the structure and texture components of Viognier are outlined in the following gray boxes. The plus signs (+) indicate a positive correlation; negative signs (-) a negative correlation, and zero (0) no association. These generalizations follow winemaker's empirical observations. SUPPORT RESEARCH Correlations with Volume, Body, Sweetness + + + Alcohol Polysaccharides and mannoproteins Gums, like Gum Arabic Alcohol, an important component to Viognier, impacts wine mouthfeel being bittersweet and producing palate hotness.8 A high (above 14.5%) alcohol level may enhance negative textural characteristics including tannin roughness and bitterness. This highlights the importance of understanding the potential alcohol level (sugar-to-ethanol conversion) specific to each vineyard site. Mannoproteins in the yeast cell wall are bound to glucans and exist in wines as polysaccharides and proteins. They are released from the cell wall by the action of an enzyme (ß-1,3-glucanase) and can impact aroma, oxygen buffering and wine stability.9,10 These so-called macromolecules provide a sense of sweetness as a result of increasing the perception of volume or body, thereby lowering the perception of acidity and the phenol elements.11 This is one reason for the addition of glucanase enzymes and/or storage sur lie. & WINE INDUSTRY NEEDS THROUGH THE AMERICAN VINEYARD FOUNDATION Finding Solutions Through Research Drs. Walker and Cousins continue to develop rootstocks resistant to phylloxera and nematodes while displaying tolerance to abiotic stressors like drought and salts, with new selections from the Walker program now available to growers. Dr. Qian and others are studying the impact of closures with different oxygen transmission rates on aroma development with a focus on volatile sulfur compounds during post bottling aging. This work should help the industry make informed closure selections. For a wealth of useful viticulture and enology research and information, visit AVF.org, iv.ucdavis.edu, enologyaccess.org, or ngwi.org. P.O. Box 5779, Napa, CA., 94581 • T: (707) 252-6911 • Email info@avf.org. Visit our Web site at www.avf.org for information on funding and current research projects Win es & Vin es F EB RUA RY 20 13 67