Napa, February 12, 2015.
While it is still early in the season, this winter is looking a lot like last year’s very dry and mild winter. The Napa Valley received one significant rain storm in December, but January set records for its lack of rainfall. February looks to be a return to more normal weather with the return of some much needed rain.
Even though the grapevines are dormant in the winter, there is a lot of work that still needs to be done in the vineyards. While the weather is dry, crews will prune the vines using one of two common pruning techniques. Spur pruning is the more popular method used in California, and involves pruning last year’s shoots down to a short, 2-bud spur. Each bud will grow into one shoot with usually two clusters each. Most grapevines have between 16 to 32 spurs, depending on size and space. Spur pruned vines might be trellised along permanent horizontal arms, called cordons or a goblet shaped, head pruned vine. It’s a very simple and quick pruning method, but it does lead to more and larger pruning cuts and wounds over the years, which can expose the vine to disease.
The other common method is cane pruning. Pruning crews will keep only one or two shoots from the previous year. The canes are laid down and taped to a horizontal trellis wire. Usually one spur for each cane will be left to provide a renewal shoot for the next year’s cane. Cane pruning involves more skill and labor, but the vines will need less maintenance later in the growing season, and they are more self-limiting.
Above: spur pruning (L) and bi-lateral cordon trellising (M). A cane pruned vine with two renewal spurs (R)
The pruning cuttings are usually gathered and burned in piles. While burning the cuttings might seem crude, it is helps to limit the spread of common grapevine diseases and viruses.
An old vineyard is pulled out and the wood is arranged in large piles. The wood is burned to prevent the spread of disease, which is usually why the vines needed to be removed, as seen in the picture above.
Another important part of vineyard maintenance is the cover crop. There are several different options for winter ground cover that will help revive and keep the soil healthy. Annual grasses are native to the region and offer a low cost-maintenance crop. Grass roots and will provide a carbon-rich organic layer to the top soil as they dry up and decompose over the summer. Many vintners like to plant Nitrogen-fixers like legumes, bell beans and clover. These plants absorb Nitrogen from the air and will return Nitrogen to the soil as they decompose.
Mustard is a beautiful and very low maintenance cover crop as seen in the picture above.
Cover crops also provide an important, multi-biotic ecology in the vineyard. A wide variety of predatory insects thrive on cover crops, and they will play an important role in controlling mites and other leaf damaging insects during the growing season. Cover crops also prevent erosion during heavy rains.
Vintners also use cover crop to help regulate the amount of moisture in the soil. In years with a lot of late spring rain, cover crop will be allowed to grow a little longer to help soak up excess water. Alternatively, like in 2014, cover crop might be tilled into the soil early in the season to help maintain soil moisture.
Winter in the Winery
Winter is a busy time in the winery. Winemakers are still keeping a keen eye on wines from the last harvest. It is very important to make sure that the new wines are biologically stable using sophisticated lab analysis. Tests are conducted to ensure that the primary fermentations are complete and the malo-lactic fermentations are either finished or progressing well.
There are aromatic white varieties that will be bottled soon, keeping the cellar crew busy preparing blends and getting the wines stabilized and filtered before bottling. It is also likely to be the first time in several months that the winemaker has had time to taste wines that have been aging in barrels from the previous vintage. Each lot will be assessed by the winemaking team, and they will put together experimental blends on the benchtop before making final blending decisions. The cellar crew will be busy throughout the winter assembling blends and topping the barrels.
As a finishing note, many of us are starting to compare notes about the 2014 vintage. There seems to be a strong consensus the 2014 Napa Valley Cabernet Sauvignon is extremely dark and rich, with extracted fruit and velvety tannins.
We couldn’t be more excited!