Leaf pulling and cluster thinning are practices we do here at Sculpterra Winery each year that have been proven to greatly increase the quality of our grapes and the resulting wine. It’s a time of year that I look forward too. It’s fun to expose the cluster and see what we have! It’s like opening up a Christmas gift, revealing the grapes hidden by the leaves. My goal in any vineyard practice is to always increase quality, taste and flavors. Leaf pulling does this by exposing the grape clusters to more light and airflow, which are crucial to the development of the crop. It’s amazing to see how this easy and small vineyard practice can alter the vines ability to ripen the fruit load. My goal in doing this is four fold:
1.) Increase light and air flow within the vine’s canopy
2.) Space out the clusters to avoid bunching up and crowding of the fruit
3.) Decrease canopy humidity
4.) Increase the rate of ripening
We leaf pull all vines under my supervision because too much leaf pulling can result in sun burning/over exposure. To achieve the right balance of sun exposure we only remove leafs on the morning side of the canopy. I started this leaf pulling practice back in 2010 and saw a great improvement in even fruit ripening. It’s also important that this practice is done in a cool week to avoid shock to young clusters. Another advantage of leaf pulling is that it helps me to accurately judge the crop load so I can better plan for the coming harvest.
In addition to leaf pulling, we also cluster thin (dropping fruit) on the varietals that produce big crops with big clusters such as Petite Sirah, Grenache and Mourvedre. Cluster thinning is done by removing the “wing” or “shoulder” of the clusters using clippers. This practice removes around a quarter to a third of the cluster’s weight. We also remove the secondary and tertiary underdeveloped clusters, allowing the vine to focus all its energy on developing the primary cluster. Our other varietals, such as Cabernet Sauvignon, Viognier, Primitivo, and Merlot produce balanced yields and do not need cluster thinning.
To recap the year’s vineyard practices so far, we have done clean and accurate pruning, followed by shoot thinning and suckering., and now we are up to leaf pulling and cluster thinning. As with any vineyard practice timing is everything. I cannot stress that enough! Next up will be a green drop. That’s where we drop more fruit; we remove the clusters that are far behind in ripening. That’s the end of the vineyard work, and then we take bucket samples (judging ripeness and sugar content in the berries) and… await the harvest!