Posted by Colleen | Cellar Activity | Posted on May 21st, 2012
The following is a grapegrowing/winemaking update from our winemaker Richard Sowalsky:
Grapevines throughout the Napa Valley have finally emerged from their winter dormancy, awakening to produce the green growth and fruiting clusters that will soon become this season’s winegrapes. To ensure that the highest quality wine is produced at harvest, springtime finds abundant activity in the vineyard similar to the frenzied activity at harvest – no rest for the weary! One reason for this intensive work is that the neatly trimmed and tidy grape vines play against type. In their natural habitat, the plants act more like true vines, sending out vegetation which clings to any vertical element in its vicinity (such as a tree or rock face), moving ever upward in search of additional sun exposure for photosynthetic energy. These wild vines also exploit height to spread their seeds through presentation of fruit where birds are most likely to dine.
This natural strategy, while clearly advantageous to the grapevines, presents a number of challenges for the winegrower. Shimmying up trees and cliffs to harvest fruit for winemaking, while a healthy if somewhat perilous activity, is time consuming, especially if the vines are few and far between. Also, individual vines in the wild will spread many small clusters throughout the vast architecture, making the harvesting of sufficient fruit to produce wine on a commercial scale essentially impossible.
Now, if all of this wild growing behavior actually resulted in better winegrape quality, then it might be advantageous to pursue as close to a wild style of growth as possible. However, vegetatively sprawling, shy yielding vines do not produce superior wines, in general, because the energy of the vine is typically unbalanced in favor of growing support and light-capturing structures (the canopy) at the expense of the production of fruit with optimal wine chemistries and sensory characteristics. Essentially, since all birds and other wild grape eaters care about is sugar for energy and all the vine is trying to accomplish is propagation, just enough resources are put into fruit production as required to optimize seed ingestion and dispersal. Winegrowers have developed ways to flip this formula such that more of the vine’s resources are directed to the fruit, increasing production and accumulation of the non-sugar elements in the grapes such as flavor and aroma compounds, tannins and pigments.
Thus, the preponderance of the efforts put forth by a fine winegrower are directed at taming the natural tendencies of the grapevine for the betterment of the final wine. But, the vines never lose their call of the wild. One of the times during the growing season when this is most apparent is a few weeks after budbreak (when the vines emerge from their winter dormancy and begin their annual cycle of growth) until bloom (when the grape flowers burst open and self-pollinate). At this time, meristem (the stem cells of a plant from which all of the green tissues grow and develop) begins to multiply and differentiate in areas of the vine which have had leaves at any time in the past, because the meristem resides in the leaf angle (the area between the leaf stem and its attachment to the plant). At this time of year, it quickly becomes obvious that during the history of even the most immaculately pruned and trained vines, there must have been leaves almost everywhere on the plant, since shoots begin to grow all over the place, including from the middle of the trunks and even from the rootstock!
Excessive shoots on a vine can have a number of negative consequences, including (1) limiting the growth of so-called primary shoots (the stronger cluster-bearing shoots pruned and trained to be optimally positioned for quality) by diluting the inherent resources of the vine; (2) excessive leafiness leading to canopy shading and humidity in the fruit zone which, in turn can increase disease pressure, limit effective photosynthesis (through shading of interior leaves) and harm fruit development (by limiting sunlight to the clusters); and (3) poor fruit set after pollination due to hormonal imbalances in the vine. Thus, after the winter activity of pruning, where the desired growth potential of the vine is determined by removal of all but a limited number of the most promising meristem buds on the dormant vine, suckering is the next vital step in assuring vine balance, leading to sufficient shoot growth to ripen a healthy and moderately exposed crop of high quality winegrapes. Timing is key: if done too early, more suckers will be encouraged to grow and the activity will need to be repeated; if done too late, the primary shoots may be stunted for the remainder of the season. Growers throughout Napa Valley are seizing this time of perfect weather and optimal vine growth to “git” those suckers – yet another step in the handcrafting of the best wine possible.