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w i nema k i n g material (excluding seeds), the likely sticking points. Tannins have to come into solution from the "inside" of the grape skins; the outer cuticle is too hard to penetrate. The most detailed examination of tannin/cell wall dynamics comes from the work of Keren Bindon at the Australian Wine Research Institute. Using mainly model wines and model fermentations, Bindon has produced a long list of intriguing results, and a concern for saving trees prohibits listing them all in this magazine. But I've included a few of the more tantalizing findings. In immature grapes, tannins tend to stick to pectins, which are plentiful at that stage. As grapes ripen, the skins get more porous. You might think that would aid extraction by providing more escape hatches, but in fact it seems to provide more places for tannins to get trapped between layers and layers of stuff. Whatever the methods of winemaking employed, any given batch of grapes seems to have a plateau maximum level of tannin extraction. Some of the tannins pried loose from their original homes end up stuck back on something else and falling out of solution by the end of fermentation. Tannins may stick onto other pieces of skin, or stray polysaccharides, or yeast/lees, in an endless round of extraction, adsorption and desorption. Extraction thus is not an either/or process—you either extract the tannins or you don't—but a complex chemical dance. Bindon's observation of a plateau effect on tannin extraction from vinifera grapes resonates with a pattern found in hybrids. Extension specialist and researcher Anna Katherine Mansfield and her cohorts at Cornell University studied several processing methods for fermentations of three hybrid reds—cold soak, enzyme additions, tannin additions and hot press (thermovinification)—and found some differences in extraction, particularly for the hot-press method. But alas, after the completion of fermentation, the level of differences in the finished wines was negligible—implying that something about the hybrid grape composition or cell wall structure was putting a very low lid on stable extraction. Bindon's trials in Australia also suggest that the presence of anthocyanins somehow helps enable extraction. Anthocyanins, too, are a non-linear bunch when it comes to extraction, having their own ways of sticking to fermentation flotsam and falling out of solution. But in some yet-to-be-explained fashion, anthocyanin levels may matter as much or more than extraction techniques. Jim Harbertson at Washington State University suggested to me that there may be different kinds of bonds at work in different cases. The "weak" hydrogen and hydrophobic bonds are the most common and most studied, but maybe there are circumstances in which tannins get strongly bonded—covalent bonds—to whatever works for them, rendering them nearly impervious to conventional winemaking methods. Jim Kennedy at California State University, Fresno, (the two Jims co-chaired How two winemakers maximize tannins in hybrids H ybrid winemakers have a more challenging problem than their colleagues working with vinifera. I talked with two of them, Matthew Spaccarelli at BenMarl Winery in New York's Hudson Valley and Derek Wilbur of Swedish Hill Vineyard in the Finger Lakes region of New York state. Both began chuckling knowingly over the phone as soon as I explained that my topic was tannin extraction. As Wilbur put Matthew Spaccarelli of BenMarl winery says he uses tannin additions to try and boost structure in his Frontenac wines. it, "We can only salivate at what could be. We can't dramatically affect things." These winemakers say that certain red hybrid varieties emerge from fermentation with a decent amount of tannin structure: Baco Noir, for example, performs this way for Spaccarelli, while Wilbur sees this effect in Chambourcin. Other varieties—BenMarl's Frontenac, Swedish Hill's Marechal Foch—need more work. Spaccarelli says his Frontenac gets very ripe and has great flavors with lots of acid, but it lacks structure and mid-palate, which he tries to address with a complicated protocol of tannin addition at the start of fermentation and at one-third sugar depletion, with oak chips in the fermentation and sometimes the cap. The modest structure he's going to get comes out early, so the wines may spend no more than three days on the skins before pressing. For his more problematic grapes, Wilbur employs a hot-press method, getting the crushed grapes to 120ºF, running them through a screw press and some initial DE After being presssed once at Swedish Hill winery, Marechal Foch grapes are put through the hot press, where they are heated up to 120ºF to extract juice. filtration, then fermenting the still-solid heavy must with red wine yeasts. (He admits to losing a lot of wine in the process.) He uses the method for certain vari- eties, but also certain vintages, and for lots affected with Botrytis, where the heat treatment neutralizes laccase. Sometimes he may add more tannins between the alcoholic and malolactic fermentation, but neither Wilbur nor Spaccarelli goes for postfermentation tannin additions, which don't integrate as well into the finished wine. T.P. Win es & Vin es N OV EM B ER 20 13 25