Aeration Questions

[Painter]

I was wondering if it is possible to over aerate wort? I use a paint stirrer on an electric drill to aerate, and it does double duty circulating the wort in the cooling bath. Last time I brewed I went a bit overboard and by the time the wort had chilled I had built up quite a head of foam. It took a couple of hours for the bubbles and foam to dissipate in my hydrometer so that I could get a proper reading. Once in the fermenter, but before fermentation started there was already a head of foam, and I got a massive blowout once the yeast kicked in. I don't know if the extreme aeration had anything to do with that, and everything else went okay.

Is there any way to know how long to aerate? As I said I use a paint stirrer on a drill. Should I aerate vigorously for a certain amount of time and then cut back to a slow speed for circulation?

 

[TANSTAAFB]

I don't think you can overdo it with a paint stirrer. There is a limit to the amount of oxygen you can introduce w/o pure O2, and even then I've read that using a stone and oxygen bottle the O2 only stays in solution for about 30 minutes. You just maxed out the upper range of manual aeration and gave the Yeastie Beasties what they wanted!

 

[Braufessor]

I don't think you can overdo it with a paint stirrer. There is a limit to the amount of oxygen you can introduce w/o pure O2, and even then I've read that using a stone and oxygen bottle the O2 only stays in solution for about 30 minutes. You just maxed out the upper range of manual aeration and gave the Yeastie Beasties what they wanted!

+1 to the above.

Also, the one thing I would maybe be a bit concerned about is if you whipped up that much foam and were waiting to take gravity reading, etc...... be careful that you are not leaving your beer exposed during that time to possible contamination. Take your gravity reading right away. Aerate, pitch yeast and close that fermenter up ASAP.

 

[Rockn_M]

I don't think you can overdo it with a paint stirrer. There is a limit to the amount of oxygen you can introduce w/o pure O2, and even then I've read that using a stone and oxygen bottle the O2 only stays in solution for about 30 minutes. You just maxed out the upper range of manual aeration and gave the Yeastie Beasties what they wanted!

+2. You're good to go. Take your OG reading add the yeast and wait...

 

[Queequeg]

With air you can only aerate to a maximum of 8ppm, this can be achieved by vigorous shaking in 5mins. So you don't need to do much more than that with a paint stirrer/drill combo. This is optimal for beers up to a SG of around 1.060, above that you need 12-14ppm which can only be achieved with pure O2.

Air pumps have been shown to be less effective than just shaking, although they are more sanitary.

 

[Conman13]

One thing I noticed is that it sounds like you are aerating hot wort. You should NOT do that. Only aerate the wort once it has reach 90 degrees or lower.

 

[TANSTAAFB]

Hot side aeration seems to be another homebrew myth. It may be a concern on the commercial scale but is not an issue at the scale we are working with according to many brewers more experienced than I.

 

[jonmohno]

Whipping up a head is what you want, I do that with my bubbeler. It will grow near the top then Ill stop,wait til it settles then do it again a few more times. Ideally though it would be good to do it intermittintaly every 1/2 hour maybe up to three-four hours maybe once an hour but I never do that or have the patience and have to worry about being carefull sanitation and exposure. Most ideally and easy would be using pure 02. And yes Ive heard you can overaerate but I think it would be tedious and hard to do and you dont want to do it either after the yeast has whent though its lag phase. I would like to aerate it again though after a few hours of pitching the yeast a but never do. And yes never aerate the wort unless its less than 80 deg and preferrabley room temp or 70 or less. Better yet what ever fermenting temps your using.

 

[Painter]

+1 to the above.

Also, the one thing I would maybe be a bit concerned about is if you whipped up that much foam and were waiting to take gravity reading, etc...... be careful that you are not leaving your beer exposed during that time to possible contamination. Take your gravity reading right away. Aerate, pitch yeast and close that fermenter up ASAP.

Yeah, I sealed everything up, so the only thing that was risking contamination was the small amount in the hydrometer.

Next time I will start serious aeration after the temp drops below 90F. Thanks for all the good comments and advice.