Chenin Blanc at Veraison

True to form, our Chenin Blanc was the last to reach veraison. Yesterday, when we went into the vineyard, we noticed that there was wide variation in the Brix level in the Chenin Blanc. Most of the Chenin Blanc appear to be around 11 Brix, but some of the Chenin Blanc are now between 16-18 Brix and are tasting very sweet. At this level of Brix, the skin on the grape is quite thin and susceptible to predation by birds, bees, etc. Since there are only a few clusters at that Brix level, we have been bagging those aberrant clusters which usually appear to be larger than the typical Chenin Blanc clusters shown on the right.
When we are working in the vineyard, we use all of our senses to get a handle on the ripening progress of our grapes. Visual cues include the change in color from green to lime green and the expansion of the clusters. Other visual cues include interest by yellow jackets and other bees. By handling the cluster, we can feel the softening of the grape skin. Tasting the grapes and comparing it with our refractometer gives us an indication of the flavor that is associated with the particular sugar level. Between 9-11 Brix, the grapes still can taste rather astringent. Above 11 Brix, the grapes are now very tart but have lost their astringency. Above 16 Brix, the grapes are noticeably sweet and the seed can be crunchy, think grape nuts, the cereal.
I've updated my tracking timeline to include veraison for Chenin Blanc: