Protecting vines from frosts

The spring frosts arrive in Champagne just as the buds on the grape vines are ready to burst, and in some years the results have been catastrophic, with almost total loss of the crop. There is one method though that the vignerons use that can save them from disaster, and that is to purposely freeze the vines.

It sounds insane, but deliberately freezing vines during nights of sub zero degree temperatures is a system that is growing in the Champagne region. But how is it different from freezing naturally, and why does it work?

In the spring evenings, while the temperature is still above zero, frequent, successive layers of water are sprayed onto the vines using rotating spray heads. As the temperature drops the outermost layer of water begins to freeze, and is quickly coated with repeated layers of water that also begin to freeze, forming a protective shield around the bud. In this way the frozen layer moves outward from the emerging buds, instead of penetrating inwards. At the same time, a tiny amount of heat is released from the water, as the last remnants of warmth leave the liquid and finally allow the water to become ice. This minute amount of captured warmth, and the ever expanding coat of ice, are what protects the heart of the bud from freezing, cocooning it and ensuring that the starting point for this years fruit is preserved.

It’s also one of the most spectacular sights to be witnessed in the vineyards of Champagne.