Adopted on the April 23, 1516, at the State Parliament in Ingolstadt by Wilhelm IV, Duke of Bavaria, the German Purity Law of 1516 – the only piece of legislation of its kind in the world – continues to offer excellent consumer protection to this day, and therefore represents something of a model food safety standard. Things were different in the Middle Ages. All kinds of devilish things were mixed in with beer – in order (allegedly) to make it more palatable and last longer. We know from historical sources that ox gall bladders, toxic and intoxicating herbs, bitumen and even soot were often used in brewing processes at that time – often with horrifying consequences. By adopting a stringent Purity Law, Wilhelm IV was able to finally bring an end to the dubious practises pursued by such sinister beer adulterators: For almost 500 years, only water, malt, hops and yeast have been permitted for use in brewing beer in Germany. The original text of the Purity Law quite literally states: “In the future, we wish that in all our towns, markets and rural areas, beer shall contain nothing more than barley, hops and water.”
You may, however, have noticed that yeast is not mentioned? It is likely that the Medieval version of the German Purity Law contained no specific mention of yeast due to the fact that fermentation by yeast spores, which are still naturally found in the air, is more or less activated by chance – with accordingly “random” quality and taste results for the finished product.
