How to Brew Gluten-Free Beer: Boiling
Today we continue our journey through the brewing process by diving into the next step: Boiling. Overall, boiling is rather similar between regular and gluten-free beer, and any differences has more to do with the hops and spices being used.
Boiling actually serves two primary purposes, as well as a few others. First, it sterilizes the beer prior to fermentation, ensuring there are no unwanted microbes that would spoil the brew. Second, it readies the wort for hops addition. In addition, the boiling process also stops all the enzymatic processes (what’s converting starch to sugar), removes certain off flavors that can be boiled off, and concentrates the wort.
The boiling process takes place inside what’s called a brew kettle, a large stainless steel or copper vat with a heating element. The heating element can be a simple burner underneath, or a more complex external, pressured boling unit, which is now quite common.
A brief word about hops. We’ll talk more about hops in a few days, but without getting too detailed, hops are female flowers that gives beer its trademark bitterness and aroma. The bitterness is influenced by the alpha acid levels in hops, while the aroma is caused by the aromatic oils. As a result, the choice of hops can greatly alter the bitterness, aroma, and flavor of the beer. Generally, hops with higher alpha levels add more bitterness, and hops with lower are used to add aroma.
The time that the hops are added also impacts the beer. Hops added earlier in the boiling phase allows more alpha acids to be isomerized, increasing bitterness, while hops added later prevents the evaporation of the oils, increasing aroma. This means that a heavily hopped beer is not necessarily bitter, depending on the time of hops used and whether it is added late in the process.
The actual boiling process itself is fairly simple. The wort is raised to a “rolling boil” and kept there for about an hour, which primarily has to do with the hop schedule, or when the hops are being added.
End of Boil
And the end of the process, the wort is bittered and aroma’d, but the hop particulates must be removed. This can be accomplished by either filtering the wort through a hopback or whirlpooling, which concentrates the particles at the center of the tank for removal. This can be done in the boil kettle, or in a separate whirlpool tank. Once the wort is cleared, it must be cooled quickly to avoid forming off flavors and prevent bacteria growth. This process usually takes place in a heat exchanger.
At the end of this stage, the wort is officially ready for fermentation–which will turn it into gluten-free beer!