September 29, 2014 by Prost Brewing
If you’ve taken a tour of the Prost brauhaus or another brewery, you’re familiar with the different steps in the brewing process. To truly understanding brewing, however, it’s important to know exactly why we do what we do in each step. Today we’re looking at the boil stage in the brewing process, in which wort is boiled with the addition of hops.
Wort is the liquid that’s formed after malt is steeped in hot water during the mash stage. After the malt particles are removed from the wort, or lautered, the wort is transferred back into the kettle to be boiled. The purpose of the boil period covers a multitude of reasons, most of which relate to the chemical changes the wort undergoes to be converted into bier. Some reasons have to do with adding color and style-specific flavor elements.
One big reason for the boil is that it sterilizes the wort, destroying any germs or bacteria that could contaminate the batch. Boiling atomizes unwanted flavor volatiles, mainly dimethylsulfide, or DMS. It also stops malt enzyme activity and lowers the wort pH level, both of which have a big impact on fermentation. Boiling the wort isomerizes hop alpha acids, coagulates proteins, and concentrates the wort. The boil darkens the wort color and forms certain toffee and nutty flavors.
Each bier style varies when it comes to the length of the boil, varieties of hops added, and at what point the hops are added. This is just one phase in the brewing process, but a very important one. You can definitely taste our dedication to excellent brewing in the finished product. Prost!