Midwest Grape Maturity Analysis 2023 (week 5)

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 5

Berry shrivel seems to be a common theme in a number of the vineyards I have been at.  This was most noticeable in the Frontenac family and La Crescent vines I have been at during harvest this week. 

Additionally, some vines that had extensive Japanese beetle damage have had slow ripening progress as well. (see photo on the right).

Berry Report Comments/Highlights

The report reflects the last 3 samples dates.

Brianna and Edelweiss

• All harvested except in our most northern location.

Crimson Pearl

• Little movement at the one location we are monitoring.

Frontenac

• Berry weight is stagnant to trending down.
• Considerable jump in pH at the Central and East Central Iowa locations.

Frontenac Blanc

• Berry weight is stagnant to trending down.

La Crescent

• We anticipate nearly all sites will be harvested before the next report.

Marechal Foch

• Moderate gains in maturity at two locations and large gains at one location.

Marquette

• Half the locations have been harvested.
• Minimal to moderate gains in maturity at the remaining locations

Petite Pearl

• None of the sample locations have been harvested.  Reports of other locations possibly starting harvest next week.
• Brix still less than 20 at all but one location, but the pH is moving into (or at) ideal maturity range.

St. Croix

• The sample location has been harvested.

St. Pepin

• Half the sites have been sampled, with the remaining site likely to be as well.

Verona

• The pH has gotten above 3.

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