Reasons For the Boil

The boil is an important step in the brewing process. It happens for four reasons. Can you guess them all? Cover up the answer, and see if you can. Read below to see if you got them all.

1. Sanitation: Boiling kills all the unwanted bug and critters in the wort. That way, when you cool it, you can inoculate it with the yeast of your choice and not have off flavors.

2. Hop Isomerization: Hops contain bittering compounds called alpha acids. However, alpha acids are not soluble in a liquid. By boiling them, they are chemically rearranged into iso-alpha acids, which are soluble in a liquid. The longer the alpha acids are boiled, the more of them get converted to iso-alpha acids (up and to a point).

3. Hot Break: When the proteins in the wort are boiled, they clump together and settle out, in hot and sour soup looking ribbons. This can help beer stability and haze issues in the final product.

4. Boil off DMS Precursors: Unless DMS is driven off, the beer will have a canned corn type aroma and flavor. This comes from a compound called Dimethyl Sulfide (DMS). The precursors for this compound can be boiled off. That is why it is important to boil with the lid off.

By the way, the question, what are the four reasons for the boil, is what I always ask when someone challenges for rank in the Atenveldt Brewer's Guild. So, if you are in the SCA, a brewer, reside in the Kingdom of Atenveldt, and wish to challenge for rank in the brewer's guild, use this as a cheat sheet. If, however, you have no idea what I'm talking about, don't worry about it; it does not apply to you.