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WINEMAKING rest of the material is where the frontier is," says Smith. And the phe- nolic frontiersfolk have a number of interesting speculations. Could be that those gallic acid hangers-on get stripped off in the acid bath of wine. Could be that short seed tannins hook up and become more skin-like, and skin tannins break down into seed-like chains. Could be that the greater seed and skin tannin extracted during extended maceration gets masked by the greater amount of polysaccharides extracted at the same time. Could be that, since big molecules like to play with other big molecules, the longer skin tannin chains are more likely to hook up with those polysaccharides, canceling out their previous astringency. Could most likely be all of the above—and more. Bruce Zoecklein of Virginia Tech points out that astringency can trump bitterness in perception of a wine's qualities, which can be a good thing. Except in badly unbalanced wines, any bitterness contributed by seed tannins is likely to be covered up, sooner or later, by the astringency from skin tannins. Many winemakers have learned that early bitterness fades with time; less fortunate wine- makers have learned that overly aggressive fining for tannin reduc- tion can bring the element of bitterness back into the spotlight. And now it's time to return to our friend the epigallocatechin, CONNECTING VINEYARD PRACTICES TO WINE QUALITY NOVEMBER 16, 2011 INNOVATIVE SEMINARS WITH WINE TRIALS • INDUSTRY TRADE SHOW • SPANISH SEMINARS the one monomeric tannin building block found only in skin tan- nin. Paul Smith notes that epigallocatechin is the subunit most susceptible to oxidation. Jim Kennedy, who on the whole is not that fond of seed tannin, suggests that its comparative resistance to oxidative reactions (since it has no epigallocatechins) may make it valuable for wine's longevity, slowing down the pace of oxygen-driven deterioration, Jim Harbertson says we don't really know the effects of epigallocatechin. I followed up my initial email exchange with Paul Smith by asking whether he thought the epigallocatechins' propensity for oxidation was overall a good thing or a bad thing, and what he sent back is a succinct expression of the state of tannin knowl- edge. Here is his response in its entirety: "We don't know if it's good or bad—if oxidized tannins are soft and mellow, then I guess it's good. If oxidized tannins are grippy and coarse, I guess it's bad!" Always diplomatic, those Aussies. Finally, one important part of wine tannin is the tannin that never gets into the wine at all. Research by Doug Adams at UC Davis, several investigators in France and Keren Bindon at the AWRI has illuminated the ways in which extracted tannins, espe- cially the longer chains, can get trapped back into the skins, a kind of self-fining process. Jim Kennedy says some wines never get half their potential tannins. As an example he uses grapes from Cali- fornia's toasty Central Valley, where skins toughen up and trap tannins as a form of self-defense against the heat. In this complex and somewhat fuzzy picture, it's hard to see seed tannins as the prime bogeyman. N A PA VA L L E Y G R A P E G R OWE R S TO PRESERVE AND PROMOT E NAPA VAL L E Y 'S WORLD-CLASS VINE YARDS napagrowers.org What if we made the seeds go away? Perhaps the strongest case for the value of seed tannin comes from knowing what happens when they are utterly banished. It's not good. Zoecklein and other researchers did some studies a while back in which they removed as many seeds as practical in the early stages of red fermentations, before there was much ethanol to pull out the seed tannin. He describes the resulting wines as having a "donut hole" where the mid-palate should be. More recently, the same issue has arisen with the hot-button tech- nology of Flash Détente. The rapid heating and vacuum-cooling of grapes with Flash Détente's version of thermovinification performs almost instant extraction of skin tannins and pigments using only heat and water (juice). Without any ethanol present, seeds remain 58 Wines & Vines OCTOBeR 2011