Aeration stone turned 5 gallons of wort into foam?

I just brewed my Kiwi Express extract kit and when I tried to aerate with my stone it all turned into foam and ended up on my kitchen floor. Did I just lose all my hop oils because clean up sure smelled like I did ?? Is there some trick to using a stone ? I am using an air compressor used for airbrushing models and I have the pressure regulator turned all the way down. Also, I didn’t have any way of keeping the stone on the bottom so I guess it was just floating around on top. I’m a welder/fabricator and have access to a lot of different stainless steel so I was thinking for next time I would tie the stone to a stainless rod and drop it in. However, if the stone is always going to foam the wort up this bad I’ll just stick to shaking the bucket for 10 minutes. I ended up getting too frustrated to mess with it any more and pitched my yeast into the bucket of foam ( hopefully it’s not all foam ). Maybe it’ll make beer. This is my 3rd brew and, so far, something always goes wrong. I’m pretty sure you’re not supposed to spend 2 hours brewing and 3 hours cleaning up the mess.

First, a disclaimer, I have absolutely NO experience aerating wort.

I do however, know Airbrushing and Aquariums.

Your air compressor was WAY too much for the job at hand. The word overkill does not do it justice!
Your average aquarium air compressor is only pushing around 5 p.s.i max, at something like 0.30 CFM.
Even if your reg goes down to 5 p.s.i., your compressor is still moving 10-15 CFM of air.

So, my advice to you is, if you still have a lot in the fermentor, let it go, and see what happens, you might like the taste! If not, then brew up another batch, go to your local pet store and pick up a $3.99 compressor and aerate with that. You will have to increase you r aeration time with it, but it shouldn’t cause a foam out.

And don’t get discouraged, this is a learning experience. I have only 2- 1 gallon kits under my belt so far, and thought I knew better than the instructions and WAY overpitched them causing flash fermentation to occur. So you are not alone in this adventure! Today I get a 5 gallon Extra Pale kit in the mail, and we shall see how I screw that one up!

Hope I helped a little,


You simply need to feed it less air pressure. You can use an aquarium pump with an inline filter, or get an oxygen bottle and regulator kit.

You can go big and get a tank of oxygen from the welding shop and a cheap oxygen regulator from Harbor Freight. If you brew a lot this is best.

To hold the stone down into the wort I place a stainless fitting over the tubing that is large enough for the tubing, but smaller that the stone itself. This weights it down. What I use is actually a 1/2" NPT stainless barb because it was laying around so anything will work. I steam sanitize the stone and fittings before use.

If you are over foaming you are feeding too much air, it’s that simple.

Doesn’t the air from the compressor also have oil in it you need an in line filter and just a aquarium pump on some other canister with O2 that has a lot less volume.

I use medical oxygen only probable available with a prescription but if your Doctor loves beer no problem in getting one 8)

Inline filters should be used on any source that is pumping atmospheric air, period. Depends on the compressor if there would be oil in the output, but I’d get the proper filter in any case.

As for oxygen, welding oxygen is fine as nothing can live in the gas. Medical grade is overkill, and even though I also have a oxygen provider certification and can get it, no reason to spend the extra $ and have yet another different tank around :slight_smile: I was using scuba tanks as well, but when they ran out of certification I just started using bulk from the welding shop. Same as the dive shop uses for mixed gas mixing.

I use a welding O2 cylinder and an aeration stone. Every time I get foaming, it’s because I’ve turned up the dial on the regulator too high. It’s a non-issue (for me) if you catch it in the first minute; left alone for 5 minutes, though, you’d have a mess.

Thanks guys, the compressor was just laying around unused so I thought I’d give it a try. I had the psi down but didn’t even think about cfm. Clearly too much air !!! I did use a Hepa inline filter so at least I had too much CLEAN air !!! I think I’ll stop in the local pet shop and get a cheap aquarium pump which should work much better. Does anyone know how long I should aerate ? I’ve seen advise on the subject range anywhere from 5 min. to an hour. In case anyone was wondering, the batch that foamed up on me is fermenting away in the closet so hopefully it’ll turn out ok. As always the feedback is greatly appreciated !! ... techniques

This article suggests 15 minutes when using an air pump.

15 minutes…roger that. Thanks NightHawk.