Assessing a Vineyard's Optimum Ripeness

Fessing up, we don't have a vineyard yet and we'll have to wait another two to three years after planting next spring in order to have grapes, but when we do, we'll be checking for the ripeness of our grapes by berry sampling of the vineyard in order to get statistically meaningful results. We will follow this protocol:

• Avoid collecting berries from the edge rows
• Collect samples from both sides of the vine
• Estimate the proportion of shaded clusters and sample accordingly
• Collect berries from the top, middle and bottom of a cluster
• Collect berries at the same time of the day for consistency

Single berries can be monitored for the sugar content by using a refractometer, but estimating the fruit maturity of the entire vineyard or vineyard block does involve collection of a representative sample. I want to be doing this approximately three weeks before harvest to understand the progression of the berry flavor. A really good diagram was provided in Practical Winery and Vineyard Journal called Understanding Grape Berry Development published in the July/August 2002 issue.

One of the many things that I learned is that the xylem flow to the berry ceases at veraison and the berry enlargement relies on the phloem sap.
After gathering my representative sample of berries, I would check for the sugar content using a hydrometer to measure the Brix, I would use a pH meter to check for the pH and I would titrate my sample for the amount of tartaric acid. I would also taste my sample of berry juice to see if I like the balance of fruit and acid and then make my harvest decision based on those parameters.