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WINEMAKING behavioral patterns. These likely variations in botrytis strain, lac- case personality and the relative levels of both substances in any given batch of grapes helps explain why winemaker anecdotes this season are so wildly diverse—everything from rotten fruit produc- ing fine wine to apparently low-laccase wines turning brown in a matter of minutes when exposed to air. Most of the time, laccase goes after phenolic compounds and degrades them into quinones, which polymerize in the presence of oxygen, forming discolored pigmented polymers. In whites, this is called browning, after the color they turn; in reds, the resulting color is simply called ugly. Laccase also makes a small contribu- tion to flattening the aromatic and flavor qualities of impacted wines, aging them prematurely (in, say, a couple months.) space, and watch what happens. While a normal wine would take weeks to oxidize toward brown, a laccase-laced wine will turn quickly with a plentiful supply of oxygen. There are also test kits on the market that refine the process considerably by standard- izing treatment of the wine and using a color chart to translate color change into laccase enzyme units. Readings from the kits get a bit more dicey with red wines; as Adrian Coulter of the Aus- tralian Wine Research Institute (AWRI) explained via email, any pink coloration left in the prepared wine sample could mask the pinkish reaction produced by laccase activity in the kits. ETS has had a more sophisticated laccase test available—actually, Botrytis is a serious issue for vineyard manager Chad Vargas (left) and winemaker David Paige (right), seen with David Adelsheim. Vargas sprays vines early at Adelsheim Vineyard to combat "bad" botrytis. This bad actor has several disagreeable habits. First, it is quite resistant to sulfur dioxide, the when-in-doubt solution to wine impurities. Second, laccase has staying power; it doesn't just do damage once but over and over, relentlessly hunting new oppor- tunities to foment oxidation. And third, it can produce delayed reactions, months after harvest, when the right combination of phenols and oxygen are present. That can mean browning in the bottle on the wine shop shelf or an unpleasant surprise when a tank or barrel gets racked and the wine is eyeballed for the first time in a couple months. Since laccase does not immediately announce its presence (the way hydrogen sulfide does, for example), any batch of suspect fruit should be tested to determine whether it's around and at what level. For enzymes, measuring the sheer volume in milli- grams per liter is possible, but not that helpful; what we want to know is how active it is. Enzyme activity gets measured in its very own set of units, a little bit like the way penicillin comes in units. For enzymes, one unit is the amount of the enzyme that catalyzes the conversion of one micro mole of substrate per minute; an al- ternate form of activity measurement, the katal, clocks in as the amount of enzyme that converts one mole of substrate per second. Testing, in other words, has to capture what the laccase does, not how much of it is in the solution. The most basic, old-fashioned qualitative test for determining whether a laccase problem exists is simply to set a glass of the wine in question on a shelf, covered, with lots of air in the head- 84 Wines & Vines MAY 2012 a panel that includes testing for botrytis, laccase and beta-glucans— for several years, but in 2011, it did a land-office business up and down the West Coast. As described by Rich DeScenzo of ETS, who developed the test, the method involves pulling out the wine pheno- lics with PVPP, then using ABTS—2,2'-azino-bis(3-ethylbenzothi- azoline-6-sulphonic acid), if you must know—as a substrate, and using a spectrophotometer to read changes in absorbance every few minutes for an hour to calculate enzyme units. Very low scores can suggest a wine needs no particular remedial action, just careful winemaking; higher unit counts imply a call to action. These test options are clearly useful, but perhaps not bulletproof. Measuring laccase activity is not like measuring Brix or pH. Rog- er Boulton at the University of California, Davis, is dubious about current test procedures, in part because of their proprietary nature, which means they have not been subjected to sufficient formal sci- entific scrutiny. The best of the tests require a certain degree of ma- nipulation of the wine sample, pulling things out or putting things in, making the test context somewhat different from the original wine matrix. And since laccase can operate over long stretches of time, tests that measure activity over seconds or minutes could provide unreliable long-term projections. Whatever the level of testing, 2011 clearly produced tens of thou- sands of gallons of laccase-compromised wines. DeScenzo says that many wineries were aware of the potential trouble from the start and have applied sound winemaking practices to mitigate the issues. But how big, really, is the problem? "We'll learn that in the next year," he says. Will this affect wine longevity? Here we have a defi- nite unknown-unknown, or as DeScenzo put it, "Who knows?" Prevention and remediation One thoroughly known-known is that prevention of botrytis is way better than removal of its creepy legacy compounds. The impact of botrytis damage within a given weather zone varies by grape cultivar, with thicker skinned, looser clustered grapes far- ing better. Cabernet Sauvignon is fairly resistant; Pinot Noir is highly vulnerable. By far the best practice in the vineyard is to start spraying early, at flowering time, before any visible signs of botrytis are evident; waiting until botrytis shows up guarantees that some level of trouble will be folded into bunches as they swell and close up, then travel into the cellar. This is a practice Chad Vargas, vineyard manager at Adelsheim Vineyard, has been using for some time and pitching to other growers in Oregon. At Chim- ney Rock in Napa, Doug Fletcher says their spray program always starts early in the season, even if the timing had nothing to do with botrytis. It limited the rot in 2011 quite well. Selective harvesting and ruthless sorting are the next line of defense. Many wineries do a two-stage harvest: a first round designed to clear away moldy clusters and other defective fruit, and then a second pass for good fruit. Further sorting happens at the winery. Trouble is, not all botrytis is conveniently exposed on the outside of clusters; some of it is bound to be tucked inside, still able to do its thing when the fruit