The character of the wood which is employed in the storage of distilled spirits also has much to do with the aroma, and also to a certain extent with the flavor of an old spirit. The process of charring the barrels in which distilled spirits are stored gives to such spirits in the United States a distinct character not possessed by similar spirits stored in plain wood.

In the storage of brandy in the south of France great care is exercised in the selection of the wood and the manufacture of the barrels. A variety of oak known as Limousin is preferred. It is believed that this wood gives up very little bitter principle to the alcohol. The principles which are extracted from the oak are not only the tannin, but also quercin, which gives a distinct aroma, and quercetin, which contributes to the yellow coloration of the distilled spirits.