Tannins on Trial

Dr. Mark Greenspan, the viticulturalist who writes the monthly column for Wine Business Monthly summarized the 2011 harvest like this, “one of the most difficult growing seasons in memory…cold, wet, and moldy would be the best descriptors” (WBM January 2012, 104-6). Here in Healdsburg, it rained in early October. Not so good. Luckily for me, I’d harvested 3 of 4 vineyards before the rains hit. Luckily for me, the outlying vineyard is in Anderson Valley, farmed by Rich Savoy, a veteran in the biz. And luckily for me, imperfect harvest scenarios are always excellent learning opportunities. Unfortunately, I too combated a rot problem. Botrytis, the intractable, fluffy, filamentous beast hiding between grapes, can be problematic for many reasons. First of all, the fungus thrives in wet, warm conditions. The October rains were notable not only for heartbreaking timing- smack dab in the midst of harvest- but also for subsequent warmth. I remember sweating though my shirt during punch downs; the weather was more sauna than sleet. This is incubator weather. The stuff just multiplied. Secondly, heavily infected fruit tastes funky. Ripe berry fruit flavors are replaced with dingy, moldy, earthy notes. Finally, botrytis courts a troublemaking enzyme called laccase. This sulfur-resistant enzyme oxidizes grape juice and persists in the finished wine. There are techniques and protocols to combat laccase, including the use of exogenous tannins, reductive winemaking, and limiting skin contact. I took advice to heart. Rich sorted like crazy in the vineyard, dropping any infected cluster in the days leading up to harvest. At harvest, the picking crew sorted aggressively in the fields, inspecting the fruit before sending it down to me in bins. And I obsessively examined each cluster by hand before the crusher. But sometimes even fastidious sorting is not enough.

I curtailed my cold soak to limit skin contact, warmed the bin to ignite a fast, hot fermentation, and added exogenous tannins to provide a compound for the laccase enzyme to chew. Or at least that’s the thinking. Provide a substitute substrate for the laccase activity and salvage the grape tannins. Try to preserve what nature provides. On 10/18/11, I had 11 units/mL of laccase in my juice. After following the fermentation protocol, I measured 28 until/mL of laccase (tested 11/8/11). I was deflated. Wine making pals offered all kinds of sound advice and suggested a number of products I might try. But I didn’t want to act under duress. Once you add something to wine, you can’t get it out. I needed time to reflect.

So last week I conducted a host of tannin trials. Obviously this is not a first choice plan of action. Nobody pays all kinds of money for premium, top notch grapes so that they can add more oak later. Just ask Brian. He pays my bills. But I am open to experimentation and exploring any avenue that might improve my wine. Plus, I was willing to play with a judicious wood tannin addition since I’d opted against 100% new oak for the Anderson Valley vineyard. The fruit is so delicate and pretty that I felt new oak barrels might clobber the crap out of the aromatics. In other words, I had some wiggle room.

Here is how it works. Laboratories provide winemakers with all sorts of tannin substitutes. Sometimes the product derives from wood tannins, the same stuff in an oak barrel. Imagine powdered wood chips or reddish sand that smells like a cozy fireplace. Every labs has their own secret combination of “proprietary wood” blends. Other times, the tannins are 100% grape tannins, culled from grape skins and seeds. Or it can be a blend of wood and grape tannins. You just grab a bunch to try and see how they taste. The labs provide guidelines for the amount you can add to your wine, ranging from low levels to quite a hefty dose. I tested 6 different tannins and tannin combinations from two different sources. I tried small, medium, and large doses. In the end, I found two winners. The first elevated the red fruit aromatics. The second added a more robust, ripe berry component. The two products yielded very different results. I decided to go with the first choice, a more restrained and subtle enhancement. I didn’t want to exchange big fruit for terroir. In the end, the wine still needs to taste like the vineyard where the grapes were born.

I’ve posted some pictures of the tannin trials below.

 I ended up adding 11 grams of tannin to each barrel - a laughably minute dose (especially since I had to buy the whole $125 bag; sorry Brian).

I also conducted a decidedly less high tech experiment. I poured a glass and left it on my counter overnight. Even without a tannin addition, it wasn’t brown in the morning (cost- $0).