Zago produces its beer with high quality raw materials. Following the traditional methods dictated by the Beer Purity Law (Reinheitsgebot).

The Reinheitsgebot (Beer Purity Law in German) is a regulation promulgated by Wilhelm IV of Bavaria in the city of Ingolstadt in 1516 and this law was born to rule beer production and sale in Bavaria. It is considered the oldest regulation, still in use, in the food hygiene field.

In the original text, the only ingredients allowed for beer production were water, barley and hops.

The regulation did not mention yeast.

It was around the year 1800 that Louis Pasteur discovered the role of microorganism in fermentation, hence, when drafting regulation yeast was not known as a beer ingredient. Master brewers generally took some “sediment” from the previous fermentation and added it to the next: this sediment generally contained the necessary organism to activate fermentation process.

Hops were added to beer as a preservative, and they were mentioned in the Reinheitsgebot with the aim of avoiding alternative preservation methods used before the introduction of hops. Medieval brewers had used several problematic ingredients to preserve beer as soot and Amanita Muscaria (fly amanita). Often other herbs were used, like nettle, which is part of the same family as hops.