The Life Cycle of a Grape vine – Harvest pt. 1
Jeff’s Corner 8-6-22
Hey, Hey, Hey,
Today we are going to conclude our five-part series on the life cycle of a grape vine.
This story will be a two-parter, with today focusing on what goes on in the vineyard leading up to harvest, while next week we’ll talk specifically about the 2022 growing season.
With our ’22 harvest underway on the Estate, I reached out to our vineyard manager extraordinaire Clint Messimer for some first-hand info, along with some help from our extremely capable chemist, Julian Maher.
Much of this story (and we’ll be discussing our red grapes) will be in Clint’s words, but first we should define some of his terminology. “Veraison” is when the grapes transition from their growth phase and begin to ripen and their color changes from green to dark purple. “Phenolic compounds” are found in the skins, and include tannin and color.
“Brix” is a scale that measures the sugar content of the grape juice. One degree Brix is equal to 1 gram of sugar per 100 grams of juice. “TA” is titratable acid and measures the volume of acid in the juice, and “pH” measures the concentration of acid. TA is measured as the number of grams of tartaric acid per liter, while pH measures the acidity or alkalinity of a liquid. The pH scale ranges from 0-14, with 7 being neutral and 0-6.9 acidic and 7.1-14 alkaline.
Now, on to Clint:
“We sample in the morning when it’s cool. We pick 100 individual berries throughout each block from every part of the clusters–sun and shade. Julian mashes them up together and does the chemistries. We’ll do an early sample towards the end of veraison just to see where we are, and then about once a week close to harvest.
So, I talked to Julian about numbers. Of course, everything varies greatly depending on near-infinite variables, but ideally we look for a pH between 3.5-3.7, Brix mid-to-higher 20’s, and TA of about 6.4 grams/liter. In the vineyard we try to keep the fruit zone open and utilize organic treatments to minimize insects and fungal development.
Also, for the last few years, we’ve been spraying a fertilizer made from brewer’s yeast at veraision that helps phenolic development before we hit the target brix. Everything else is determined by weather–we may have to pull (pick) early because of rain or let it hang because of rain. The big thing is, as you know, we want the best maturity while maintaining chemistries we can work with.”
Thanks, Clint and Julian!!!
Stay tuned next week when both Clint and our Commander in Chief, Brian Heath, talk about the very challenging 2022 vintage…