Wine Microclimatology: Degree Day System and Climate Areas
My notes from a wine class. See notes at end.
Wine Microclimatology
Soil is everything in France – it differs from region to region and with each region the soil content can have a dramatic effect on the finished wine. In the U.S., weather is everything, and there are many microclimates that affect the grapes and finished wine.
Degree Day System
Growing Degree Days is the data for the average for heat accumulation in a region. Knowing this can help plan a season, compare seasons and regions, and even predict a season. Based on the assumption that 50º (in Fahrenheit) is the minimum average for all areas of a wine growing region, and April 1 to October 31 is the growing season.
As follows (simple example):
- April 1 – 51º = 1 DD (meaning 1 degree over 50)
- April 2 – 60º = 10 DD (meaning 10 degrees over 50)
- April 3 – 47º = 0 DD (meaning you don’t count backwards or subtract)
- So the three days = 11 DD. You continue through the season and count all the degrees through the end of the season. The formula is GDD = (high + low) / 2 – 50 (whereas 50 is the minimum average for the wine growing region).
Climate Areas
| Zone | Growing Degree Days | Regions | Wines |
|---|---|---|---|
| Zone 1 | 0 – 2500 | Willamette Valley, OR. Puget Sound, WA. Champagne, Burgundy, and Loire Valley, France. Rhine Valley, Germany. Central Coast, CA. Rio Negro, Argentina. Nova Scotia, Canada. Kent and Sussex, England. | Gamay, Pinot Noir, Riesling, Müller-Thurgau, Chenin Blanc, Chardonnay. |
| Zone 2 | 2501 – 3000 | Bordeaux, France. Columbia Valley, WA. Adelaide Hills and Coonawarra, Australia. Piedmont, Italy. Douro Valley, Portugal. | Gamay, Cabernet Sauvignon, Merlot, Cabernet Franc, Chadonnay (toastier ones). |
| Zone 3 | 3001 – 3500 | Umbriam Alto Adige and Friuli, Italy. Northern Rhône, France. Monticello, Virgina. Medocino and Sonoma Valley, CA. Rioja, Spain. Margaret River, Austrailia. Krasnodar, Russia. | Syrah, Grenache, Zinfadel. |
| Zone 4 | 3501 – 4000 | Tuscany and Verona, Italy. Corsica, Southern Rhône, Roussillon and Languedoc, France. Northern Sonoma and Napa Valley, CA. Barossa Valley, Australia. Stellenbosch, South Africa. Estremadura, Portugal. | Grenache. Big, bold flavors of other varieties. Higher alcohol. Richer flavor. |
| Zone 5 | 4001 – up | Lodi, CA. Madeira, Portugal. Jerez, Spain. Patras, Greece. Hunter Valley, Australia. Apulia, Italy. North Africa / Morocco. | Very heady wines. Fortified wines. Table wines. |
When I was 19, I was a student of Western Culinary Institute in Portland, OR, before Career Education Corporation and Le Cordon Bleu took it over. I graduated in 1993, and at that time WCI was a great place to learn. Many of the pans I cooked on interestingly still had HMCI (Horst Mager Culinary Institute) inscribed on the handles. Above were notes that I found in a file folder from a wine class that I took when I was a student. The notes are from my personal tasting notes. Enjoy!
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