Brew Tips: Stopping Wort Boil-Overs

Off-week bonus post!  This is a quick tip for keeping your kettle from foaming over during the boil.

Use a fan to blow air across the top of your brew pot, and it will not foam over.  I recommend using the low setting, at least if you have a large fan like mine.  Try not to direct too much air at the kettle itself, as this will cool it and use more fuel to maintain the same boil.  But, less air across the top of the wort will give you less foam-stopping power, so there is a balance.  I turn the fan off as soon as I trust the pot to not foam anymore, or at least a few minutes before the end of the boil for sanitary purposes.

You can also use a fan directed at the top of the wort to increase your boil-off rate, though you should still keep it to a reasonable rate.

I’m not sure if anyone else has ever publicized this idea, but I have never seen anything other than a recommendation to stir or spray down the foam with a spray bottle.


No more foam-overs!  This garage is dirty enough without an overflowing kettle.

– Dennis,
Life, Fermented

About Dennis
Home brewer, home chef, garage tinkerer. Author of Life Fermented blog.

4 Responses to Brew Tips: Stopping Wort Boil-Overs

  1. Jon D. says:

    Excellent tip with the fan for reducing wort volume. I’ll have to try that next time I have more volume than wanted. Recently I got greedy about the remaining sugars I had left after my fly sparge had only brought the wort down to 1.022 SG and I figured I would squeeze a little more out. I thought another 1/2 gallon to cook down wouldn’t be a big deal, but I had forgotten I also had the volume of a 2 liter starter on the stir plate. Added time became longer and longer. Half hour to heat more water and sparge plus the 75 minute boil turned into about 100-110 minutes. Added time I hadn’t planned on standing out on the hot patio without sunscreen.

    • Dennis says:

      Unfortunately I have never actually measured the effect of the fan on evaporation increase. I’ve only used the fan for that twice, and it both cases it was a last second “oh s**t, I have too much wort and I don’t want to boil longer and mess up my hop timing.” But, it is definitely noticeable. The anti-foam use actually came later when I had a beer that refused to stop foaming. By 30 minutes into the boil, I was getting really tired of stirring the foam down. I still haven’t figured out what that beer’s deal was, but now I use it as a kettle watcher at the start of my boils to make sure it doesn’t foam when I’m not looking.
      – Dennis

  2. beeryben says:

    Adding copper coins is also meant to be beneficial in avoiding boil overs. I suspect this is meant to be linked to the interaction of proteins with copper. I’ve used this idea and found that the main benefit is that the coins stat to make a ‘tinkeling’ sound before it comes to the boil. Acts as a sort of alarm to make sure you are nearby when it all foams up!

    • Dennis says:

      Good tip! I’ve also heard some murmuring about some fringe benifits of adding copper to the boil- micro nutrients or something. I’ve never dug in to find out if there is any good science behind it, but some people swear by dropping a small length of tubing or a few pennies into the kettle if they don’t use a wort chiller.
      – Dennis

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: