The main ingredients of beer in the Middle Ages were malted barley, water and yeast. Sometimes, rosemary and thyme were added to prevent the beer from spoiling (action against mold and yeast) and to give it flavor. This beer was cloudy and contained many proteins and carbohydrates, which made it a very nutritious drink, consumed by both the peasants and the nobility.
The European monks refined the process and institutionalized the use of hops for its flavor and its properties as a preservative.
Before knowing hops, northern Europeans used aromatic herbs and wild plants, achieving a lighter beer, of short duration and unsuitable for transport. In the 12th century, the German king Juan Primus, known as Gambrinus, fought hunger in his domains through the cultivation of barley, which greatly impelled the manufacture of beer.