The Beer Purity Law is the oldest currently applicable food regulation in the world. It is also the outcome of a legal development reaching back several centuries in Germany, whereby the relevant legal authorities and bodies strove with their various decrees to improve the quality of beer, a staple item in the popular diet. Similar regulations are also to be found outside Germany and in the mists of early pre-Christian antiquity.

The first documented references on German soil date from the reign of Barbarossa. In 1156 the Emperor gave the City of Augsburg a new statute, the famous "Justitia Civitatis Augustensis", which is the oldest German town charter. And it gets down to the business of beer: "A publican who serves bad beer or gives short measure shall suffer punishment ..." The punishment, incidentally, was quite considerable, in the amount of 5 Gulden. The licence was withdrawn on a third offence.

A further regulation is known from the City of Nuremberg. In 1393 the local City Council decided to use only malted barley for the brewing of beer. Some 30 years later, in 1420, Munich Town Hall decided to store or "lager" the brew before sale.

In 1447 the good people of Regensburg engaged their Municipal Physician to inspect the locally brewed beer and to take particular interest as regards the ingredients used in the brewing of beer. His alarming reports led to a Brewing Regulation in 1453.

The people of Munich were also concerned about the quality of their beer in 1363. They charged 12 members of the City Council with the task of beer quality assurance. And in 1447, they expressly instructed the brewers to use only malted barley, hops and water for the brewing of beer; "... und sonst nichts darein oder darunter tun oder man straffe es fuer valsch" - and neither add nor subtract any ingredient lest it be treated as a case of adulteration.
40 years later Duke Albrecht IV confirmed the demand of the Munich City Council, for he had seen that the beer trade in North Germany was flourishing mainly because the local brewers' guilds insisted on the production of good quality beer.

In 1998 mediaeval Runneburg in Thuringian Weißensee delivered up a hitherto unknown document on the subject of beer purity. Article 12 of the Tavern Law "Statuta thaberna" of 1434 states that beer may not be brewed except with hops, malt and water. It goes on to impose penalties for offences against the rules of the brewer's art.

A little later, in 1493, Duke George the Wealthy followed suit and decreed this rule for his entire Duchy of Bavaria-Landshut, the old Bavarian heartland: "Brewers and others shall use only malted barley, hops and water for the brewing of beer; brewers, publicans and others adding any other ingredients to the beer are liable to incur physical and material punishment."
All these decrees were duly controlled: beer inspectors paid regular visits to the brewers, tasted and tested the beer. They themselves were bound by strict regulations and were not allowed to undertake more than six inspections in one day. On inspection days they were also not allowed to eat foods that might affect the taste buds, or drink wine or even smoke tobacco.