Literally "Purity Decree". In 1516 the Bavarian king Ludwig declared that beer may only be produced with malt, water and hops (yeast was originally not included because it's existance was unknown at the time). All the German tribes would eventually adopt this decree, so it is today known both as the Bavarian Reinheitsgebot of 1516, as well as the German Reinheitsgebot of 1516. When yeast was later discovered, it was added as the fourth ingredient allowed in beer in Germany. This is in stark contrast to the over 100 ingredients allowed in beer in North America.
IS THE REAL BEER LAW INSTITUTED IN GERMANY IN 1516ONLY MALTED BARLEY, MALTED WHEAT, HOPS, AND WATER CAN BE USED TO MAKE BEER. YOU WILL BE IN VIOLATION OF THE LAW IF YOU USE SUGAR TO MAKE "BEER"
A purity law which regulates the production of beer and various other drinks and foodstuffs.