The past couple days have seen overnight temperatures dip dangerously low as dawn approached in the Napa Valley. We say dangerous as we look through the the eyes of the young, budding shoots in the vineyards. The frost, if it sets in, can destroy the young crop and put a winery’s annual harvest (and potential profit) in jeopardy. That’s why you see (and we constantly hear) the large vineyard fans buzzing in the early morning hours this time of year. This isn’t something that’s unique to Napa either.
Aside from the fans, we’ve noticed the overhead vineyard sprinkler systems working some major overtime in the past week or so. These systems aren’t used in the way you might think. Here’s a good explanation from the St. Supery Winery website:
When the water comes in contact with the vine, it begins to freeze, which gives off energy, known as latent heat of fusion. As ice forms around the bud, it acts as an insulator while this energy keeps the cells of the young vine tissue from freezing, slightly above 32 degrees.
The other typical method is the burning of smudge pots, which we don’t see too much of in the valley. Here’s a glimpse of what things looked like at sunrise on Sunday morning in Napa: