Cluster Thinning

It is dry, very dry. No appreciable rainfall for nearly a month. However, with a few exceptions the vines look great. Shoot growth is slowing and the canopy remains green and vibrant. Remember that grapevines originate from the Mediterranean where it rarely rains in the summer.

The exceptions are young vines and vines on shallow soils. They are showing signs of stress. They could use a refreshing rain.

The developing grape berries have entered lag phase. About 50 days after flowering, cell division completes and the berries pause in their formation. This is the ideal time to cluster thin. If we were to start earlier, the remaining berries would compensate and grow larger. This would produce tighter and larger clusters which is not good for quality.

We cluster thin for several reasons:

1. Aeration in the fruit zone. It is important to have good air circulation and even sun exposure around individual bunches. No crowding and entanglement. You want to be able to see the outline of each individual cluster.

2. Uniformity. Each shoot and each vine needs to ripen the same level of crop. The winegrower makes decisions about vine and crop balance. It is not left to chance.

3. Concentration. Lower yields equate to more core, density, and texture in the resulting wine. It gets down to the critical question: what kind of wine do we want to make?

Cluster thinning is an extremely important and consequential winemaking decision.

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Linden Vineyards / Learn More / Latest at Linden | Journal/Field Notes: July 18, 2023