Northern Grapes Project August News You Can Use: Grape Berry Ripening

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News You Can Use


Grape Berry Ripening

Marquette clusters during veraison at Parley Lake Winery in Waconia, MN.

photo: Seth Reid

As we head into August, veraison will commence, and along with it, thoughts of when to harvest. A great deal of research has been conducted to characterize the ripening profiles of Vitis vinifera cultivars, which helps growers make informed decisions regarding harvest. However, little is known about the changes in chemical composition during ripening of the cold hardy cultivars.

Recent work at the University of Minnesota tracked changes in fruit composition of 11 cultivars, including seven cold hardy cultivars. The results are a good start to understanding more about the changes that occur in fruit chemistry as berries ripen. Included in this months’ News You Can Use are two publications that summarize this work; the first is “Understanding the Ripening Chemistry of Cold-Hardy Wine Grapes to Predict Optimal Harvest Time,” an article originally published in the August 2012 issue of Northern Grapes News. The second is “Fruit Ripening Profiles of Cold Climate Wine Grape Cultivars,” a research report that was written as part of the Year 2 Northern Grapes Progress Report.

Additional Resources:

Fruit Maturity Evaluation of Wine Grapes for Harvest Planning (

Collecting Berry Samples to Assess Grape Maturity


Using a Refractometer to Measure the Sugar Concentration of Sap and Syrup (

Chrislyn A. Particka, PhD

Extension Support Specialist

Cornell University

Department of Horticultural Sciences

630 W. North Street

Geneva, NY 14456


315-787-2449 (desk)

315-787-2216 (fax)