While most "eaux de vie" from the Alpine regions of Europe only rest very briefly in glass containers, others are aged in wooden casks before bottling. Thus, calvados, an apple-based spirit from northwestern France, is required by law to spend at least two years in wood, and most producers also offer much older products to the market (up to 20 years or more). Some "slivovitz" are also aged in wooden casks, giving them their golden or amber color and some additional flavors.