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April 2016 WINES&VINES 37 GROUNDED GRAPEGROWING and vegetation to prevent the fire from climbing into the crown of trees if you live in a forested area. The next most devastating problem is when the edges of the vineyard either burn or are exposed to superheated air from the flames that essentially cook the vascular system of the vines and wilt the fruit. Having originated from ripar- ian areas, wine grapes are not adapted to fire (unlike so many of our California natives, which depend on fire for propagation and renewal). The bark is very thin and provides no insulation from heat. The overall mass of the wood in the vine is relatively small, so even internal cells found in the woody xylem are likely to die from heated sap that might actually boil when ex- posed to hot air accompanying a fire. Vines damaged by fire or heat rarely recover; if the vines are either charred or the leaves are com- pletely desiccated, odds are good the vines have been severely damaged and are not going to recover. You may see some buds push, but often the vascular system of the vines is seriously compromised in the woody portions, and there is likely to be irreversible damage. Careful as- sessment of your vineyard with a knowledgeable viticulturist is advised. The vines need to be checked by cutting into the cambium and in- specting the health of the xylem and phloem. Looking for discoloration, loss of turgor pressure in the cells (this requires close inspection with a hand lens or dissecting microscope), cutting into lateral buds to see if they are still green and viable are all part of the inspection procedures that should be made. You can wait and see how the vines push the following growing season and retrain vines, if needed. The nature of the smoke problem Forest and brush fires produce large volumes of smoke that can travel many miles and settle into valleys and other low-lying areas. Smoke contains visible, airborne byproducts of com- bustion made up of water vapor, particulates (including tar, ash, carbon and partially burnt fuel fragments) and many gases (CO 2 , CO, N 2 O, S 2 O, NH 3 , CH 4 , NOx, ozone and other non- methane hydrocarbons.) Smoke represents 1.5%-2% of the gases produced by fire. Lignin in wood is the primary source of phe- nolic compounds that cause smoke flavors in wine. Wood is composed of about 20%-30% lignin, which gives wood strength and lines water conductive tissues. Phenolic compounds associated with smoke include guaiacol and 4-methylguaiacol. Both are chemicals that we can taste in smoked food flavoring. These com- pounds can be found in oak barrels during the toasting process. On their own, these two chemi- cals have flavor profiles described as bacon, burnt bacon, smoky, leather, spicy, phenolic, salami and smoked salmon, which doesn't sound so bad. The problem is that there are more than 70 other compounds in forest fire smoke that also produce very undesirable flavors and odors that can described as, "like licking an ashtray," burnt garbage, burnt potato and a campfire that has been drenched with water. The phenolic-forming compounds from smoke concentrate more in the skins of the fruit than in the pulp and juice. If you can minimize the skin's contact with juice during harvest, you will also minimize smoke taste. This works fine for white varieties, but since skin contact is essential to make red wine, there is an inherent problem when red grapes be- come smoke affected. Both guaiacol and 4-methylguaiacol can be detected in the fruit by gas chromatography, so it is possible to sample fruit before harvest to make picking decisions. While these compounds aren't neces- Sap might actually boil when exposed to hot air accompanying a fire. One of the pioneers in engineering crossflow filtration, Romfil Crossflow systems have been filtering wine since 1998. Romfil crossflow stands for quality and precision in manufacturing and processing. Our filters are simple, gentle, modular and thoughtfully engineered. With capacity ranges from 200 gallons an hour to over 5000 gallons an hour – we have a system to simplify your life. FOR THE LOVE OF WINE West: 707-864-5800 East: 540-825-5700 info@euromachinesusa.com – www.euromachinesusa.com ROMFIL CROSSFLOW FILTRATION