Hops are one of the main ingredients in beer. The German Reinheitsgebot (=purity law) specifies only four ingredients which are allowed to make a good brew. Besides hops, the other ingredients are water, malt, and yeast. But hops are special, because the premium hops from German growing regions balances the sweetness of the malt sugars. Hops are responsible for providing a refreshing finish.
Hops are usually divided into two main categories: bittering and aroma. Bittering hop are high in alpha acids. Aroma hops are usually around lower in alpha acids and contribute a more desirable aroma and flavor to the beer. Several hop varieties are in-between and used for both purposes.
The main bittering agent is the alpha acid resin which is insoluble in water until isomerized by boiling. They are added early so the heat from the boiling wort has time to break down or isomerize the acid. This iso-alpha acid is even more bitter and, unlike the alpha acid, soluble. It is therefore dissolved into the wort and carried into the final beer. The longer the boil, the greater the percentage of isomerization and the bitterer the beer turns out.
By adding different varieties of hops at different times during the boil, a more complex hop profile can be established that provides a balance of hop bitterness, taste and aroma. Premium aroma hops from German growing regions are excellent for adding fruity flavors, such as mandarin or melon, to innovative beer styles In addition German hops are protected by the EU and are products of origin. German hops are displaying the EU quality labels PDO (Protected Designation of Origin) respectively PGI (Protected Geographical Indication) and guarantee European high quality products.