Most California wines are best to drink within a year of the bottling date. Sparkling, white, sweet blush, Nouveau, and red table wines are intended for early consumption and should be stored only for a short period. These wines must be kept cool while storing. Only a few California wine varietals – such as Riesling, Nebbiolo, Cabernet Sauvignon, and Syrah – can be stored for a long term.
Initially, the wines were stored in oak barrels and kept in large temperature-controlled warehouses. The wines kept in such barrels got easily degraded due to absorption of air and moisture by wood. Moreover, a significant amount of wine was lost due to evaporation. To overcome this, the California wine industry adopted a new storage technique using tunnels. Tunnels are extremely humid and have a low evaporation rate, nearly half that of barrels. Today, wineries in Napa Valley and Sonoma County use this tunneling technique to store the wines.
In northern California, over 130 underground caves are available for wine aging and barrel storage. Some of these caves are open for public tours.
While storing California wines, certain factors need to be considered. A constant temperature is essential for both short and long term wine storage, as temperature changes can have a negative effect on the aging process. The best temperature for long term California wine storage is between 50 and 59 degrees Fahrenheit.
A low humidity often results in dry corks, which allows oxygen to come in contact with the wine. A relative humidity of 75% is best for storing California red wines and 85% for storing white wines. Always keep the wines – especially the red wines – away from direct sunlight.
In most cases, the California wine bottles are stored horizontally, so that the wines come in contact with the cork and keep it wet. But in some wineries, there are stored in inverted position. This is not suitable for long-term California wine storage. A good storage location needs to be free from vibrations and shocks, as they deteriorate the wine prematurely.