How To Prevent Brew Boil Over

Boil overs are bound to occur when homebrewing beer. Unless you have access to a professional brewery, you’ll experience a boil over at some point or another. The good news is that it typically doesn’t ruin a brew, but the bad news is that it can — and will — affect its characteristics. When a boil over occurs, some of the hops and break material may escape. As you probably know, hops are used to balance the beer’s sweetness, while break materials affect its head.

Allowing your brew to boil over increases the chance of it possessing poor flavors, low body, or other unwanted characteristics. However, preventing a boil over isn’t always an easy task. You have to leave the top open so the steam can escape, making the brew susceptible to boiling over. There are, however, a couple of techniques brewers can use to help reduce the chance of a boil over.

Beer boiling: photo by adambarhan.

Stir, Stir, Stir!

You might be surprised to learn just how much of an effect stirring has on a batch of a homebrew beer. When the brew begins to develop a thick layer of foam on the top, take a wooden spoon or spatula and stir it for a couple of minutes. This offers several unique benefits, one of which is the blending of your hops and ingredients. Stirring the brew will prevents unwanted buildups of hops at the bottom of the pot.

The real benefit of stirring your brew is the simple fact that it breaks up the foamy top layer; thus, helping to prevent boil overs.

Spray It

Another technique that many brewers use to prevent boil overs is involves spraying the brew with cold water. The next time you brew a batch of beer, keep a water bottle nearby for instances where it begins to rise. Spraying the top with just a single misting of water will prevent the boil overs.

Note: only spray your brew when it’s absolutely necessary, as spraying it too much will water down your beer.

Fermcap

Fermcap is a product designed specifically for the prevention of brew boil overs. This powerful, insoluble ingredient is added during fermentation to help settle the beer and reduce the chance of boil overs. Best of all, it does not affect the beer’s flavor, texture, body, aroma or other characteristics. Simply add a 1-2 drops per gallon of beer for optimal effectiveness.