For beer, the main thing is purity. For almost 500 years, throughout the German-speaking area, beer has been brewed in accordance with the German Beer Purity Order.
To avoid counterfeiting the amber drink, Duke Wilhelm IV of Bavaria (1493-1550) issued this law in 1516, which German brewers still adhere to today. Generally speaking, it can be considered the oldest prescription for food. And what does it say? This law requires brewers to use only barley, hops and water, while leaving wheat and rye to the bakers. About yeast - you can't brew beer without it! - not a word in the law, because at that time no one knew about them yet.
However, mankind did not become addicted to beer in the Middle Ages. Brewing is closely related to the cultivation of grain crops and is approximately six thousand years old. The first beer was brewed by humans in 4000 BC. e. in ancient Babylon, where it became a folk drink soon after. Later, the art of brewing was adopted from the Babylonians by the Egyptians, and then by the ancient Romans.
In the Middle Ages, thanks to the monastic brethren, the drink spread throughout Europe. That is why many European countries have their own brewing tradition and beer brands. So, in England it is "Guness", in the Netherlands - "Heineken", in Denmark - "Tuborg". Nevertheless, Germany has been and remains a real stronghold of beer culture: there are about a thousand breweries here, and they produce 5,000 different brands of beer.