Grappa is an alcoholic beverage made from the squished skins, seeds and stems (the pomace) left over after grapes have been pressed to make wine. Grappa is the Italian name. In France, it is called eau-de-vie de marc or simply marc. Some grappa is also produced in California, where it is called grappa.
Initially, grappa was made as an effort to use every speck of the grape, and was especially important as a source of income in years of bad harvest. It has evolved, however, into something a lot more sophisticated than simple leftovers. In Italy, there are varietal grappas, made from the skins of a single variety of grapes. In the Burgundy and Champagne regions in France, some winemakers buy the pomace of other growers to ensure an adequate supply. Particularly fine grappas are matured in oak barrels, which gives them a light brown color. Otherwise it is clear. It is extremely potent.