As winemakers, one of the main keys to making great wines is being able to have control over our temperatures at all stages - starting with the fermentation and ending with the cellar.
The temperature of a fermentation has a direct influence on the quality of the wine. This is because wine yeast create different compounds at various temperatures. Cooler temperature fermentations preserve more aromatic esters and create lean, focused wines, but often with reduced mouthfeel. Warmer fermentations give greater complexity and mouthfeel, but at the loss of the original clarity of the fruit. In addition, the warmer a fermentation gets, the higher the amount of H2S will be produced. For winemakers, the goal is to be able to control the fermentation temperature within a desired range for the style of wine we are trying to make while never allowing it to get too hot.
Cellaring / Storage:
Once the fermentation is over, the temperature the wine is cellared at also has an effect on the quality of the wine. Wine is constantly developing and changing, and temperature determines how fast and harmonious this evolution will be. The ideal temperature for a slow and steady evolution is around 55 F (13 C). When wine is stored at cooler temperatures (less than 55 F), its development slows down but this doesn't really harm the wine. On the other hand, storing wine at higher temperatures can definitely have a detrimental effect on the wine over time. Heat causes wine to lose its fruit and volatile aromatic qualities, rendering it flat and lifeless over time.
(Note: Quick swings in temperature are more harmful to a wine than slightly elevated, steadily-held ones. In other words, even though 55 F is the ideal storage temp, it is better to store wine at a steady 60-65 F than to swing between 55-75 F every couple of days. This is why indoor closets are better than garages for wine storage!)
The Tools to Cool!:
MoreWine! offers two basic set-ups for controlling your winemaking temperatures: