Wines & Vines

30 WINES&VINES February 2018 VIEWPOINT impacted by both climate and fruit maturity. Problems with under-ripe fruit include the following: 17 • Insufficient pigments, • Limited extraction, • Limited desirable flavors, which lim- its tannin capacity. The problems with over-ripe fruit or wide varia- tions in fruit maturity include the following: • Loss of color, • High alcohol capacity, which can de- stabilize color-tannin complexes, • Significant loss of reductive strength. The change in phenolic content as a func- tion of excessive fruit maturity can lower the reductive strength by a factor of 10. 17 In some regions, the use of hyperoxygenation for some white cultivars may become more important in helping to provide longevity. (See Enology Notes #160 at vtwines.info.) Grape nitrogen Both YAN (yeast assimilable nitrogen) and micronutrients are essential for fermentation. Nitrogen availability can be considered a ter- roir factor, being correlated to both red and white wine quality, particularly where soil moisture is not limiting. Fruit nitrogen may change notably in some regions as a result of increases in temperature and precipitation extremes. As such, it may be even more important in the future to monitor each block, each season, for nitrogen status. This monitoring should be done in concert with the understanding of differences in optimum YAN in red and white grapes, cultivar differ- ences and difference between native plant- derived nitrogen and fermentation adjuncts. Grape/must temperature The importance of energy management should be highlighted as a result of climate change. Many regions around the world have sustain- ability programs to help winegrowers under- stand the importance of sustainable practices including thermal control. These programs will become even more important to the industry in the future. Winemakers and winery owners should understand that energy is a variable, not a fixed cost. Each producer, large or small, interested in saving money should answer the following questions: • What is the relationship between en- ergy cost and your bottom line? • How is energy used at your facility, and where? • What are the ways to reduce energy consumption? • Are you benchmarking or measuring your energy use? The advantage of benchmarking or deter- mining your energy use lies in the ability to answer these questions by measuring, contrast- ing and charting progress. It is like the old saying: "If you do not know where you are going, any road will take you there!" AUTHOR'S NOTE This text is adapted from a presentation given at the 18th annual British Columbia Grape and Wine Conference in Penticton, B.C. I am not a climate scientist nor a spe- cialist in this area. However, I have been involved in winemaking and enology education for more than 40 years in North America and various wine regions around the world. As such, I have observed some of the impacts of climate change on our industry. My goal is to review several issues related to climate change, winemaking practices and the attitudes regarding a changing climate in the United States.

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