make them more pliable and easily bent into the final barrel shape In Europe, the barrel interior is heated with a small brazier of burning wood scraps to 400ºF/200ºC Once the softened staves have been tightly hooped into their final positions, the interior is “toasted” further at 300–400ºF/150–200ºC, for to 20 minutes, depending on the degree of cooking desired: less for wine barrels, more for spirits In the United States, the heat treatment for whiskey barrels is more extreme The hooped staves are first steamed to soften them, and then the barrel interior is charred with an open gas burner for from 15 to 45 seconds Barrel Flavors Several things happen when alcoholic liquids are stored in new barrels First, the liquid extracts soluble materials that contribute color and flavor, including tannins, oak and clove and vanilla aromas, and the sugars, browning-reaction products, and smoky volatiles formed when the barrel was heated In the charred American barrels used for whiskey, the carbonized surface acts something like an activated charcoal absorbant, removing some materials from the whiskey and so accelerating the maturation of its flavor Gaps and pores in the wood allow the liquid to absorb limited amounts of oxygen And the rich chemical brew of wine or spirits, wood components, and oxygen slowly undergoes innumerable reactions and evolves toward a harmonious equilibrium New oak barrels give a pronounced flavor to liquids stored in them, one that can overwhelm the inherent qualities of delicate wines The producer can control the contribution of the wood by limiting the aging time in new barrels, or by working with used barrels, which have already had much of their flavor components extracted Barrel Fermentation Some wines and vinegars are fermented in ... whiskey and so accelerating the maturation of its flavor Gaps and pores in the wood allow the liquid to absorb limited amounts of oxygen And the rich chemical brew of wine or spirits, wood components, and oxygen slowly... The producer can control the contribution of the wood by limiting the aging time in new barrels, or by working with used barrels, which have already had much of their flavor components extracted... reactions and evolves toward a harmonious equilibrium New oak barrels give a pronounced flavor to liquids stored in them, one that can overwhelm the inherent qualities of delicate wines The producer can control the