What are the big fans in the vineyards? Are they to cool off the grapes in the summer?
Actually, no. They’re to keep the grapes warm in the spring, when there is danger of frost which can damage the young shoots. When the temperature gets down to around 34° Fahrenheit, smudge pots (diesel heaters) are started to heat up the air. The fans then blow the warm air through the vineyard. Wind machines circulate air in the vineyards to help keep the new shoots from freezing. (Photo courtesy of Napa Valley Vintners Association.) Another method of frost protection is the overhead sprinklers that you might have seen. The sprinklers spray the vines, covering the shoots with water, which then freezes. Interestingly, this insulated ice jacket protects the shoots, keeping them just warm enough to avoid freezing themselves.
