Barrel ageing is an important step in the winemaking process. It is also used for certain other alcohols, such as some specialty beers. During the barrel ageing process, the wine mellows, becoming more complex and pleasant to drink. Different types of barrels are used, depending on the wine, and the wine may age for varying amounts of time as well. Decisions about the mechanics of the process are made by the wine maker.
When wine is made, grapes are pressed and then allowed to ferment, often in stainless steel tanks. Once the wine has been sufficiently fermented, it is “racked,” or pumped out of the barrels and filtered to remove the yeast, arresting the fermentation process. After racking, the wine is far from finished. It has a raw, aggressive, intense flavor. Barrel ageing allows the wine to settle, creating the rich and complex flavors which most people associate with wine.
The practice of barrel ageing is ancient. Wine makers before the birth of Christ understood that resting wine produced a better final product. The barrels were also easier to handle and ship, making wine a major export of regions which were capable of supporting grapes. During the barrel aging process, the wine is stored in cool, humid caves to minimize evaporation. Controlled oxidation of the wine also occurs, changing the flavor and texture of the wine.
Several different types of barrels are used. In many instances, wine is barrel aged in oak barrels, which change the flavor profile of the wine as it ages. Barrel ageing which takes place in oak barrels will yield a more tannic wine, as the tannins in the oak leach out. The wine may also have flavors of earth, vanilla, and humus, again courtesy of the oak. The oak itself changes over time, ultimately becoming “neutral,” meaning that it will not have an impact on the flavor of the wine. Cement and stainless steel barrels are also used for neutral aging.
People who are knowledgeable about wine often ask how it was aged. Many wineries publish profiles of their wines which include information about the barrel ageing process. The profile typically states what kind of barrel was used and how long the wine was aged. If the barrel is made from wood, American and French oak are the two most common choices for barrel ageing, although other aromatic woods may be used for unique wines.
The winemaking process is extremely complex, and barrel ageing is only one part of it. The wine maker must also be able to select the best grapes, and the winery crew must handle the grapes and wine well throughout the manufacturing process. When winemaking goes awry, the unpleasant results are readily detectable to consumers.