Have you ever wondered why some wines are aged in oak and some are not? Barrel aging in winemaking is a beautiful, necessary, and often overlooked  process.  Without oak, many wines we love would not exist as we know them.  Traditionally speaking, most white wines are not aged on oak, while most reds are.  However, as wine makers experiment with new processes, many combinations are becoming available.  The most common types of oak used in wine barrels are American and French. American oak barrels add flavors of coconut, vanilla, cedar, and dill.  European Oak adds flavors of vanilla, clove, allspice, and cedar.  In addition to imparting new flavors, oak barrels impart texture as well.  Many wines get their tannins from oak barrels.  You may also hear people refer to their oak barrels as “neutral.”  Oak barrels have the highest impact on wine during the first four years of use.  After four years, the barrels become “neutral,” meaning that they do not impart such strong flavors and textures as new barrels.  Fun fact: Evaporation occurs during oak barrel aging.  Both water and alcohol diffuse outward through the staves of a closed oak barrel.  A 50-gallon barrel of cabernet sauvignon, for example, may lose as much as 5 to 6 gallons of liquid per year.  Evaporation is one of the many factors that impact the maturation of wine in barrels.  This evaporation process has been nicknamed the “angel’s share.”

References: Wine Folly: The Essential Guide to Wine (Puckette & Hammack); The Wine Bible (MacNeil)