The distillation of cider must be carried out in two stages in a pot still in order to obtain the Pays d'Auge AOC label for Calvados. The cider is heated to 176° F (80°C), hence the importance of the manometers. The result is called small waters and contains 28 to 30% alcohol. The second heating, at a maximum of 161 °F (72°C), reveals the final eau de vie once the head and tail alcohols have been removed, leaving only the heart of the alcohol. The liquid then ages for at least two years in oak barrels. Unlike wine, Calvados no longer ages once bottled.