By Harold McGee
Oak barrels are expensive, so only relatively expensive wines and spirits are aged in them. There are other ways of getting oak flavor into less expensive products. Boisés, extracts made by boiling wood chips in water, are a traditional finishing additive in French brandies, including Cognac and Armagnac. In recent years, large-volume winemakers have begun putting barrel staves, oak chips, and even sawdust into wines while they mature in containers made of steel and other inert materials.