Issue link: http://winesandvines.uberflip.com/i/197145
W I N E M A KI N G the ASEV Symposium) says the evidence for this high-test bonding so far is mostly anecdotal, but quite intriguing. There may be varietal differences in extractability, even among vinifera cultivars, let alone between vinifera and hybrids, but this has not gotten much attention yet. (My amateur speculation: Maybe grapes like Tannat and Sagrantino, sources of infamously tannic wines, are just more willing to let their tannins go?) It is also entirely possible that site and viticultural factors exert an influence that persists all the way The level of tannins in the grapes is the best general predictor of tannin levels in wine, even if it's not perfect. through winemaking. Doug Adams at the University of California, Davis, for example, mentioned a field trial done a few years back on own-rooted Pommard clone Pinot Noir in Oregon involving two vineyards near each other, one on a hillside, one on flatlands. Tannin levels in the fruit were comparable; the hillside grapes had three times as much tannin in the finished wines. Go figure. Measuring and managing Right now, there is no handy-dandy instant tannin extractability assay, no nifty attachment to your refractometer that indicates you will get 43.8% of the tannins out of these grapes. What's more, there is no particular demand for such a test. "I've never heard a winemaker say, 'If I could only get my cell wall interaction right…'" Kennedy observes. But some kind of rapid test might help growers and winemakers avoid unpleasant surprises of over- or under-extraction that complicate the pursuit of a particular wine style. Bindon insists that the level of tannins in the grapes is the best general predictor of tannin levels in wine, even if it's not perfect. She thinks relatively primitive tests can easily be done to get a grip on extractability: macerating grapes in an acidified solution of 15% ethanol, or hitting grapes with a 70% acetone solution. Instead, what vinifera winemakers generally do is get used to their fruit sources and learn to live with them. Careful winemakers track their various lots year after year, and if a particular block is always tannindeficient, or a particular vineyard is always tannin-heavy, those lots are treated accordingly and set on track for a particular wine tier or blend. This kind of informed experience doesn't explain all of the tannin extraction anomalies, but it handles them in a practical fashion over time. Good red hybrid winemakers face much tougher challenges (see "How two winemakers maximize tannins in hybrids" on page 25) and certainly earn their pay in meeting them. But even in their wineries, the mysteries of extraction and non-extraction probably aren't the most pressing problem at harvest time. Advancing our understanding of tannin dynamics could lead to more informed decisions both in the vineyard and the winery, and someday that will happen. In the meantime, there are plenty of cool riddles wrapped in these mysteries, all part of the great tannin enigma. Tim Patterson is the author of "Home Winemaking for Dummies." He writes about wine and makes his own in Berkeley, Calif. Years of experience as a journalist, combined with a contrarian streak, make him interested in getting to the bottom of wine stories, casting a critical eye on conventional wisdom in the process. 26 W in e s & V i ne s NOV E M B E R 20 13