Since the 20th century, the "Purity Law" has stipulated that beer may only consist of hops, malt, yeast and water. This is exactly what was laid down in the Land Code of the Duchy of Bavaria as early as 1516. On today's day, April 23. Today is virtually the annual day of all German beers.
Since 2005, the Beer Ordinance regulates what may be called "beer". Here the purity law was loosened a little, so that now the most different creations romp on the beer market.