that microbes can “spoil” fruit juice and gruel
into something both delicious and pleasantly
inebriating. A few centuries ago, winemakers
and distillers discovered another remarkable
piece of good luck: simply storing wine,
spirits, and vinegars in wood barrels turns out
to give them a new and complementary
dimension of flavor.
Oak and Its Qualities Though chestnut and
cedar have been used in Europe and redwood
in the United States, most barrels for aging
wines and spirits are made from oak. Oak
heartwood, the older inner wood, is a mass of
dead cells that supports the outer living
layers. The heartwood cells are filled with
compounds that deter boring insects. These
are mainly tannins, but they include such
aromatic compounds as clove-like eugenol,
vanilla-like vanillin, and oaky “oak lactones,”
relatives of the characteristic aromatics of
coconut and peach. From 90 to 95% of the