Duke Wilhelm IV of Bavaria signed the Reinheitsgebot, a law to ensure the purity of beer that specific a limited number of ingredients.
The early 1500s experienced economic and agricultural tensions which saw brewers and bakers competing to purchase grain to produce their goods. In an effort to avoid price inflation, the Reinheitsgebot consequently limited brewers to only use barley while wheat and rye were exclusively made available to bakers for bread.
The original purity law was signed in Ingolstadt and stated that beer brewed in Bavaria could only contain barley, hops and water. As the political situation in Germany changed over the subsequent centuries the Reinheitsgebot continued to be a central piece of legislation. Its pan-German implementation was even a prerequisite for Bavaria joining the German Empire in 1871. The strict nature of the law meant that it has often met opposition from some German brewers leading to some adaptations. These include recognising that yeast is required for fermentation, and permitting malted ‘grains’ rather than just barley to be used.
Despite the subsequent changes, some people have blamed the Reinheitsgebot for the lack of diversity in German beers. As recently as 2016 the German daily newspaper Der Spiegel criticised the law for denying brewers the opportunity to experiment with new ingredients and styles. Consequently some breweries have begun to create brews that don’t follow the law, but they are not allowed to call them ‘beer’.
Meanwhile the Reinheitsgebot continues to have a number of supporters, and German beers brewed to its specifications have the status of a protected traditional foodstuff under European Union law.