The MGWII has teamed up with Randall Vos (ISU Extension) to perform grape maturity analysis for multiple locations across Iowa and one site in Illinois.
Each week during the harvest season you’ll receive this email with a link to the data for multiple cultivars and the current week’s analysis of soluble solids (Brix), pH, TA and berry weights.
Please consider sampling your own vineyard as well to get an accurate picture of grape ripening. Please contact Randall (rjvos@iastate.edu) or the MGWII (wine@iastate.edu) if you have any questions, or need help to get a sampling program started.
2023 Midwest Wine Grape Berry Composition Report: Week 2
Welcome to week 3 of the Midwest Wine Grape Berry Composition Report!
This week, we again had some cultivars that did not have significant changes in pH. Part of this could be due to sample variation from week to week. But, given that most of the samples in this week’s report were taken before the heat wave, there will likely be some changes in maturity between this report and the next.
Several growers have harvested Brianna, Edelweiss, and Itasca. For the Edelweiss and Brianna that were not harvested, there were significant reductions in the TA from the last report.
Last week, I spoke with some growers in the central and southern parts of the region who were anticipating harvesting next week. Instead of harvesting next week, they are doing some significant harvests of Frontenac Blanc, La Crescent, La Crosse, Marquette, St. Croix, and St. Pepin this week.
I have had a few questions about how this year’s ripening compares with last year. To generalize, I would say that this year, in some cultivars, the brix seems to be a bit lower when comparing the brix at the same pH values as last year. My typical suggestion is to prioritize pH over brix when determining when to harvest (obviously, flavor and aroma are also extremely important) since brix can vary considerably between year and location due to vine and weather factors.
Please don’t hesitate to contact us with suggestions on how to improve our report!
Last week, I spoke with some growers in the central and southern parts of the region who were anticipating harvesting next week. Instead of harvesting next week, they are doing some significant harvests of Frontenac Blanc, La Crescent, La Crosse, Marquette, St. Croix, and St. Pepin this week.
I have had a few questions about how this year’s ripening compares with last year. To generalize, I would say that this year, in some cultivars, the brix seems to be a bit lower when comparing the brix at the same pH values as last year. My typical suggestion is to prioritize pH over brix when determining when to harvest (obviously, flavor and aroma are also extremely important) since brix can vary considerably between year and location due to vine and weather factors.
Please don’t hesitate to contact us with suggestions on how to improve our report!
Commercial Fruit Crops Field Specialist
Iowa State University Extension & Outreach