The SOMM Journal

June / July 2015

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90 { THE SOMM JOURNAL } JUNE/JULY 2015 Physiological Changes The impact of climate change on viticulture and winemaking is not a simple beast. In fact, while temperature increases are the primary culprit for spurring possible dramatic changes in how grapes are grown and wine is made in the future, there are many other factors that are affected by climate change. As global daytime temperatures continue to increase, research has shown that different physiological changes in the grape vine occur and will continue to occur. Events like bud break, bloom, veraison and harvest dates are happening sooner than ever before and are predicted to occur even sooner as global daytime temperatures increase. Additionally, not only are these important developmental events in the grapevine going to occur earlier and earlier, but the number of days in between these events will also shorten. Specifically, with every 1 o C increase, it is predicted that there will be an accompanying 5 to 10 day earlier date for these physiological events. Studies have shown that earlier events like veraison could have tremendous impacts on wine quality, with the majority of those impacts leading toward the negative territory. If veraison, the start of the ripening phase for grapes, starts earlier in the season, then the ripening process will also occur earlier in the season and when the temperatures are at their hottest in many places. Earlier veraison and ripening spells major changes in the chem- istry of the grape, including increased sugar levels, decreased acid levels and decreased anthocyanin, pyrazine and methoxypyrazine levels. Increased sugar levels, in turn, lead to increased alcohol levels as well as changes in wine flavor and mouthfeel. Decreased anthocyanin levels lead to less stable color characteristics and quality in red wines, while decreased pyrazine levels lead to fewer wines having the undesirable sensory characteristic of "green" or "vegetal." Overall, earlier veraison and ripening as a result of climate change will markedly change the chemical composition of grapes, ultimately leading to marked changes in the sensory characteristics and quality of the finished wine. Pests & Disease Pressure Not only do current models predict that increased global tem- peratures will affect the physiological development and growth of the grape vine, but increased pressure from pests and other diseases will also become more prominent as time goes on. Like grape vines, insects and pests also have ideal temperature ranges Hot Intermediate Warm Cool 66.2oF - 75.2oF 62.6oF - 66.2oF 59oF - 62.6oF 55.4oF - 59oF GRAPE GROWING CLIMATES MULLER-THURGAU PINOT GRIS GEWURZTRAMINER RIESLING PINOT NOIR CHARDONNAY SAUVIGNON BLANC SEMILLON CABERNET FRANC TEMPRANILLO DOLCETTO MERLOT MALBEC VIOGNIER SYRAH TABLE GRAPES CABERNET SAUVIGNON SANGIOVESE GRENACHE CARIGNANE ZINFANDEL NEBBIOLO RAISINS Grape Colors Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Colors Map Colors Grape Map Colors Map Colors Map Colors Data sourced from the works of Dr. Gregory Jones. http://www.sou.edu/envirostudies/faculty/jones.html Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread Grape Colors Map Colors Light blue bar on bottom -> teal / turquiose 10-15 cool -> 40 -> top use reg orange get rid of 1 dial (orange smaller) -> spread out to 3 columns - convert to Farenheight - ll in space type bigger spread INFOGRAPHIC: TOM DONCHEZ { wine science }

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