The main ingredients of the beer in the middle ages were the malted barley, water and yeast. In occasions, added rosemary and thyme to prevent the beer from being spoiled (action against mildew, mold and yeasts), and to give it flavor. This beer was cloudy and contained a lot of protein and carbohydrates, which turned into a drink very nutritious, consumed by both the peasants as the nobility.
The monks europeans refined the process and institutionalised the use of hops for its flavour and its properties as a preservative.
Before knowing the hops, the northern europeans used aromatic herbs and wild plants, making a beer more light, of short duration and not suitable for transport. In the TWELFTH century, the king of German John Primus, known as Gambrinus , fought hunger in their domains through the cultivation of barley, which promoted greatly the manufacture of the beer.