Stumbled on this patent, filed in 1996, while looking for something else. Sounds delicious:

An extract of an oak aged alcoholic product is produced by adding a food grade solvent, such as ethyl acetate, to the oak aged alcoholic product and mixing the two liquids. The resulting mixture is allowed to separate into two layers, a first layer and a second layer. The first layer, including the food grade solvent, flavors, color, alcohol (i.e., ethanol) and water, is separated from the second layer. The solvent is then removed from the first layer to produce the extract. The extract can be added to a less costly alcoholic beverage, such as grain neutral spirits, or sugar beet spirits, to produce a beverage having the taste of a mature oak aged alcoholic beverage. Also disclosed is an accelerated whisky maturation method, including combining an alcoholic distillate with toasted oak chips, heating and aerating and/or oxygenating the resulting mixture to produce an accelerated oak aged alcoholic product. The toasted oak chips are then removed.