My posts for the month of January have been devoted to our winegrowing climate. Today I will focus on degree days. They are important to growing grapes because they determine how the climate of a particular place is in sync with what will grow well there. Wikipedia says, “A degree day is a measure of heating or cooling. Total degree days from an appropriate starting date are used to plan the planting of crops and management of pests and pest control timing.”
Dry Creek Valley is ranked as a Region II. This means there are between 2501 to 3000 growing-degree days. This is the way wine growing regions are classified and was developed by A. J. Winkler and M. Amerine in 1944 at UC Davis (go Aggies). How they defined the method was by taking the sum of degree days over 50 degrees Fahrenheit from April 1 until October 31. This is how Regions 1-V were born.
As quoted from their definition, "It is believed that Region I and II are the best for most varietals as they produce the best dry table wines with light to medium body and good balance." When looking at Region V, which has the highest heat over the time period, this would not be considered the best for wine grapes at over 4000 degree days. I’ll wrap up with a toast to my grandparents for finding this hospitable corner of Dry Creek Valley 88 years ago.
Region II in Dry Creek Valley-a summertime view of our Cabernet Sauvignon.