What is "fumarium"

A fumarium was a smoke chamber used in Ancient Rome to enhance the flavor of wine through artificially " aging" the wine. Amphorae were placed in the chamber, which was built on top of a heated hearth, in order to impart a smoky flavor in the wine that also seemed to sharpen the acidity. The wine would sometimes come out of the fumarium with a paler color. In his book Vintage: The Story of Wine, Hugh Johnson noted that Pliny the Elder and Columella did not recommend that "first-growth wines" like Falernian, Caecuban, and Alban be smoked.