According to EC law, Trappist ale may only come from 10 abbeys of the Trappist order, six in Belgium, two in the Netherlands, one in Austria and one in the United States, that still brew beer on their premises. Although the styles may differ widely among them, they share a common trait of being top-fermented, strong, bottle-conditioned, complex, and fully-flavored brews. These can often improve with some years of cellaring. Trappist ales are among the most complex and old-fashioned of beers that one can find—little wonder that many connoisseurs treat them as the holy grail of beer drinking.