петак, 24. мај 2013.

Wine Cellar and Storage of Wine

Wine Cellar


A wine cellar is a storage room for wine in bottles or barrels, or more rarely in carboys, amphorae or plastic containers. In an active wine cellar, important factors such as temperature and humidity are maintained by a climate control system. In contrast, passive wine cellars are not climate-controlled, and are usually built underground to reduce temperature swings. An aboveground wine cellar is often called a wine room, while a small wine cellar (less than 500 bottles) is sometimes termed a wine closet. The household department responsible for the storage, care and service of wine in a great mediaeval house was termed the buttery.

Three factors that have the most pronounced effect on wine in storage: light, humidity and temperature.

Light

Strong, direct sunlight or incandescent light can adversely react with phenolic compounds in wine and create potential wine faults. Delicate, light-bodied white wines run the greatest risk from light exposure and are often packaged in darkly tinted wine bottles that offer some protection from the light. Wines packaged in clear, light green and blue colored bottles are the most vulnerable to light and may need extra precautions for storage. For example, the Champagne house of Louis Roederer uses cellophane wrap to protect its premium cuvee Cristal from light, the wine being packaged in a clear bottle. In the cellar, wines are stored in corrugated boxes or wooden crates to protect the wines from direct light.

Humidity

Some degree of humidity is required in order to keep wines with cork enclosures from drying out. Even when wine bottles are stored on their sides, one side of the cork is still exposed to air. If the cork begins to dry out, it can allow oxygen to enter the bottle, filling the ullage space and possibly causing the wine to spoil or oxidize. Excessive humidity can also pose the risk of damaging wine labels, which may hinder identification or hurt potential resale value. 75% humidity is often cited as ideal but there is very little significant research to definitively establish an optimal range.

Temperature

Madeira is exposed to high temperatures during its winemaking process and is thereby able to sustain exposure to higher temperatures more easily than other wines.
Wine is very susceptible to changes in temperature, with temperature control being an important consideration in wine storage. If the wine is exposed to too high a temperature (25 °C) for long periods of time, it may become spoilt or "cooked" and develop off flavors that taste raisiny or stewed. The exact length of time that a wine is at risk of exposure to high temperatures will vary depending on the wine, with some wines (such as Madeira which is exposed to high temperatures during its winemaking) being able to sustain exposure to high temperatures more easily than other, more delicate wines (such as Riesling). If the wine is exposed to temperatures that are too cold, the wine can freeze and expand, causing the cork to be pushed out; this will allow more oxygen to be exposed to the wine. Dramatic temperature swings can also cause adverse chemical reactions in the wine that may lead to a variety of wine faults.
In general, a wine has a greater potential to develop complexity and a more aromatic bouquet if it is allowed to age slowly in a relatively cool environment. The lower the temperature, the more slowly a wine develops. On average, the rate of chemical reactions in wine doubles with each 8 °C increase in temperature. Wine can be stored at temperatures as high as 21 °C without long-term negative effect.

Vibration

Although anecdotal information regarding the contributions of vibration in wine storage states that it contributes to the accelerated aging of wine with adverse effects, this remains a research area with relatively little data. In a particular study, vibrations of different frequencies have been shown to have their own distinct effect on the chemistry of the wine. The study concludes, "Vibration could be used to accelerate the aging of wine, but in most cases, this may lead to negative effects in wine quality. Therefore, to store red wines with limited changes in physico-chemical properties, vibrations should be minimized''.