Issue link: http://winesandvines.uberflip.com/i/66135
CO VER S T OR Y The enological pantry: tannins and enzymes W hen reaching for tannins and enzymes to adjust leafroll-affected must or wine, consider these things: Experienced winemakers recommend grape-based tannins in these cases, rather than oak tannins. Note that grape-based tannins can be either skin tannins, which have a softer tannic expression, or seed tan- nins, which have a more pronounced expres- sion. Ferco makes a skin-only tannin called Grap'tan S and a seed-only option called Grap'tan TC. For a little of each, Scott'tan Taming high acid Since leafroll virus delays veraison and ripening, both white and red cultivars can show a lower pH and higher titratable acidity. Depending on winemaking style, this may or may not be an issue—especially in white wines. Climatic variations and geographic effects greatly accentuate leafroll. Therefore, this par- ticular impact is felt more during cool years than hot ones. For cool-climate growers who have difficulty ripening non-affected fruit, dealing with virus-affected fruit is especially troublesome. "Sugar-level reduction is fairly minimal in warmer growing YOUR SUCCESS IS OUR PRIORITY makes Uva'Tan, which contains both skin- and seed-derived tannins. Extraction rate and form are two things to consider when selecting an appropriate enzyme. Some enzymes extract more than others. As far as form goes, granular is ac- ceptable for most winemakers, but liquid can represent a welcomed convenience dur- ing the hectic pace of crush. With liquid enzymes, all that's needed is a graduated cylinder to measure out a dose. There's no need to bust out a gram scale and then mix the measured amount into solution. Lalle- mand makes Lallzymes EX, which is gentler for early to market reds and an EX-V version for even more tannin extraction—both come in granular form. Enartis Zym Couleur comes in both granular and liquid form and is rec- ommended for fruit that has an unbalanced tannin/anthocyanin ratio. Scottzymes makes liquid tannins—Color Pro for a gentler ex- pression, and Color X for a more pronounced tannin expression. —K. K. areas. The hang time trend negates this issue in terms of sugar development because people are dehydrating the fruit anyways. If it's a loose cluster variety, and you're in a dry place, it's easy to leave the fruit on the vine longer to ripen," Harbertson said. Due to the reduced photosynthetic capacity of the leafroll- affected leaves, Joel Peterson of Ravenswood advised that fruit should be left on the vine a little longer for ripening and acid respiration. Once the fruit reaches the cellar, Peterson reported that since pHs are lower and titratable acids are higher, his fermentations are clean and trouble-free. He does, ScottLabs_May08 4/2/08 9:53 PM Page 1 Wines & Vines JUne 2011 35