Historically & presently, this elixir is made only by the Carthusian monks following an ancient recipe, and is called Herbal Elixir of the Grande-Chartreuse. The selection, crushing and mixing of 130 secret herbs and natural plants used in producing the liqueurs of completely natural color, is done in the monastery by two monks. This liqueur is aged for several years in huge oak casks and placed into the world's longest liqueur cellar for maturation. Even today the formula remains a mystery which modern investigation methods have not been able to penetrate!