Understanding Grape Berry Development

One of my go to articles was published in 2002 in Practical Vineyard and Winery and is called Understanding Grape Berry Development. This article is especially meaningful to us now that we are taking care of grapes. The following chart that is found in the article is a visual summation of what goes on during grape berry development.

The above chart tell us a lot of information at a glance from flowering to berry ripening:

• The change in xylem and phloem flow
• The change in berry size
• What and when the various chemical compounds begin to accumulate in the grape berry
• When véraison begins
• How long after flowering can you expect full berry ripening
• The increase in ^oBrix as a function of time

Relevant to what we are seeing now, is that when véraison occurs the ^oBrix of the grape is between 4 and 7. In this respect, our Auxerrois seems to be miles ahead of our Chenin Blanc. The chart also says that it takes 60 days from véraison to full ripeness. That would put us some where in mid October for our Chenin Blanc.
Today, while we took a break from mowing the weeds, we checked the ^oBrix of our Auxerrois and Chenin Blanc. Our Auxerrois is still on the course to ripen earlier than our Chenin Blanc. We are tasting our grapes when we check the ^oBrix and we are getting pretty good at telling what it is by taste. The Chenin Blanc at ^oBrix 14 is acquiring the flavors of Chenin Blanc. When we check the ^oBrix of our grapes, we are also looking at the color of the seeds.