barrel fermentation, winemaking technique of fermenting grape juice or must in small barrels rather than in a larger fermentation vessel. The technique is used principally for white wines because of the difficulty of extracting through a barrel’s small bung-hole the mass of skins and seeds which necessarily remains after red wine fermentation, although in the late 1990s, fermentation of red wine in barrel, said to improve oak integration and mouthfeel, gained in popularity. In Burgundy, California, and especially Australia, however, some winemakers deliberately put pressed red wines which still retain some unfermented sugars into barrel, thus allowing completion of red wine fermentation in barrel in an attempt to make softer, more approachable wines.