Midwest Grape Maturity Analysis 08/15/2023

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 2 of the Midwest Wine Grape Berry Composition Report! 

In this week’s report, we posted both the week 1 and week 2 data.  The data from the same sites have been subdivided with shading as well.

While it’s difficult to generalize ripening when we are dealing with several sites and cultivars, I will try and highlight a few trends.

 The pH did not change as much as I had anticipated it might. However, there were considerable increases in pH in the Jo Daviess County, Illinois samples. While most samples had moderate increases in brix and decrease in TA, this was more pronounced in the samples from our more northern sites in Webster County (IA) and Jo Daviess County (IL). 

There are some reports of Brianna being harvested in central Iowa, along with some growers watching their Edelweiss very closely. The forecast next week looks warm, so that could have the potential to advance ripening more quickly. 

There is a good chance next week that we will start picking the early harvests for the Vine to Wine project that the Midwest Grape and Wine Industry Institute (MGWII) and I are working on with Frontenac Blanc and La Crescent. We will be harvesting those plots at three different times during the season. If you were not at the 2023 Iowa Specialty Producers Conference, the participants did some sensory analysis from the 2022 La Crescent wines that the MGWII made from the fruit harvested at different times. Some of the results I discussed in part of the Optimum ripeness parameters webinar. 

Please don’t hesitate to contact us with suggestions on how to improve our report!