The genetics in our Cold Climate grape varieties combine to present some major challenges in wine making. The first is that juice from our varieties tend to have very high acid levels. One common way to manage high acid levels is to let the grapes hang until the acid levels drop. That works for some varieties but with other varieties, the berries shrivel or “raisin” suddenly making it almost impossible to get any juice from the berries. Another approach is to balance the acid with added sugar. With some varieties, this works fine because our customer wants a sweeter wine.

A second problem with juice from Cold Climate grapes is that while it appears to have tannin when it is first juiced, by the time fermentation is done, the tannin has been consumed in the process. We would like to keep the tannin because it adds mouthfeel and complexity to the finished wine. It appears that tannin binds to protein in the wine regardless of whether we are talking about natural grape tannins or ellagic tannins from oak barrel ageing. As a result, dry red wines made from Cold Climate grapes appear to be lighter and less complex than dry red wine made from Vitis vinifera grapes. The Midwest wine industry and research institutions that support us are working to understand the processes involved and to find solutions to the problem.