04 Feb Are cold weather and snow good for grapevines?

Surely, when you see the fields covered in white or feel the harshness of winter in Rioja Alavesa, you have wondered if our vines suffer in these temperatures. The short answer is that the cold is not only good, but necessary, as long as it comes at the right time.

Iñigo Berzal, the winery’s winemaker, clarifies this fundamental issue for understanding the quality cycle of our wines.

The importance of the “vegetative pause”
The secret to why the cold does not damage the plant in January, but can be fatal in May, lies in the state of the vine. During the winter, the plant is in vegetative dormancy, asleep or dormant. In this state, the cold does not affect it negatively.

Vegetative dormancy is the winter rest period during which the vine stops growing and ceases visible activity to protect itself from low temperatures. During this phase, the plant enters a state of dormancy where sap stops actively circulating and leaves fall, allowing the vine to concentrate its energy on its woody structures. It is a natural survival response that occurs whenever the plant is dormant, preventing extreme cold from damaging its vital tissues.

This period coincides with the coldest months of the year and usually lasts from late fall to early spring, when rising temperatures reactivate the biological cycle. The importance of this phase lies in the fact that it allows the vine to strengthen and prepare for the next harvest.

However, the scenario changes dramatically when spring arrives. As our winemaker points out: “Spring frosts are not good because the vegetative state is no longer dormant.” At that point, the sap is already flowing and the new shoots are exposed; a sudden drop in temperature would freeze those shoots, compromising the harvest.

The three great benefits of winter

When the cold and snow arrive in moderation, without reaching historic extremes such as those of the famous Filomena storm, it brings us three competitive advantages for wine quality:

Strategic water reserve: Snow is a form of slow irrigation. As it melts slowly, the water penetrates deeply and gradually into the soil, increasing the water reserves that the vines will need to withstand hot summers.

Natural disinfection: Extreme cold acts as a biological “cleaner.” It helps eliminate microorganisms and small insects that live in wood and could survive milder winters, becoming pests when spring arrives.

Wood healing: After pruning, the cold helps the wood heal faster and better, protecting the plant’s structure for the new cycle.

Disinfect, nourish, and strengthen

For Dominio de Berzal, a proper winter is the key to healthy, balanced vines. The cold disinfects, the snowmelt nourishes, and the rest period strengthens. So, the next time you see snow on our vineyards, remember that nature is quietly working away for the next vintage.