<P> Historically, the restriction on ingredients led to the extinction of many brewing traditions and local beer specialties, such as North German spiced beer and cherry beer . Only a few regional beer varieties, such as Kölner Kölsch, Gosler Gose, or Düsseldorfer Altbier, survived its implementation . However, modern versions of the law have contained significant exceptions for different types of beer (such as top - fermented beers), for export beers, and for different regions . The basic law now declares that only malted grains, hops, water and yeast are permitted . </P> <P> In response to the growth of craft breweries globally, some commentators, German brewers, and even German politicians have argued that the Reinheitsgebot has slowed Germany's adoption of beer trends popular in the rest of the world, such as Belgian lambics and American craft styles . In late 2015, Bavarian brewers allegedly voted in favor of a revision to the beer laws to allow other natural ingredients . </P> <P> The earliest documented mention of beer by a German nobleman is the granting of a brewing licence by Emperor Otto II to the church at Liege (now Belgium), awarded in 974 . A variety of other beer regulations also existed in Germany during the late Middle Ages, including in Nuremberg in 1293, Erfurt in 1351, and Weißensee in 1434 . </P> <P> The Bavarian order of 1516 formed the basis of rules that spread slowly throughout Germany . Bavaria insisted on its application throughout Germany as a precondition of German unification in 1871 . The move encountered strong resistance from brewers outside Bavaria, and imperial law of 1873 taxed the use of other ingredients (rather than banning them) when used by Northern German brewers . It was not until 1906 that the law was applied consistently across all of Germany, and it was not formally referred to as Reinheitsgebot until the Weimar Republic . </P>

Who decreed that all bavarian beer must conform to the reinheitsgebot the beer purity law