Is it possible to over aerate???

[bgough]

...by just shaking the carboy?

 

[Beerrific]

No. The max oxygen you can get in there using air is 8ppm where ideal levels are 10-15ppm (with over-oxygenation being at least >15ppm).

Wyeast Laboratories. Customer Service FAQs

(EDIT: I assumed you mean pre-pitching not after fermentation. If post fermentation, then yes shaking can over oxygenate.)

 

[PatMac]

Before you pitch the yeast - shake it all you want.

After you pitch the yeast - keep the shaking to a bare minimum.

 

[Revvy]

It takes a lot of splashing to do any damage, someone on basic brewing years ago, (Palmer, or Chris Colby of BYO) said that in order to truly provide enough O2 to oxydize our beers it would take pumping and entire one of our red oxygen bottle/airstones into our beer AFTER fermentation is complete.

Most of the splashing intentional or accidental that we do in the course of our brewing will not harm it...

And beside Oxygenation damage isn't immediate anyway, most of us would have our beer drunk long before it would happen.

 

[pava]

Before you pitch the yeast - shake it all you want.

After you pitch the yeast - keep the shaking to a bare minimum.

This actually brings up something I have always wondered about. My typical routine is, once the wort is at pitching temps I throw in the yeast and then immediately shake like hell for at least 5 minutes.

Have I been doing this backwards, should you really not shake up the carboy even directly after the yeast is pitched??

 

[BarleyWater]

It's fine to pitch and then shake, I do it all the time to make sure there's no yeast stuck to the sides of the carboy that doesn't get down to the wort. You just don't want to shake after fermentation has begun, because it could lead to the possibility of oxidation.

Although, this is very unlikely, because the carboy is filled with CO2 after fermentation, so it would require you to remove the airlock and stopper, or shake it after or while transferring. Shaking a little after fermentation has started is perfectly fine, and sometimes helps to keep flocculant yeast in suspension so they can finish their job.

 

[neb_brewer]

What about the use of something like a paint mixer hooked up to the drill? Too over the top?

I saw a video of somebody doing this somewhere on the internet.

 

[BarleyWater]

Check this out. The experiment could have been done better, but I think we came to some good conclusions. https://www.homebrewtalk.com/f13/surprising-aeration-results-79762/

 

[david_42]

Surprising experiments aside, I'll go with the folks from Wyeast. Inline O2 gives about double the ppm that you get with an air pump and stone. And that's double what you can get by shaking.

I am not prepared to argue with a guy who can lift a full carboy over his head and shake it. AND he was wearing a white lab coat.

 

[ChshreCat]

I don't even worry about shaking my wort. I pour it through a strainer into the pail, and then since I do partial boils I need to top up. So, I get bottled spring water for my top up, pour a third of it in, cap the jug and shake that up good before pouring in the rest. I usually get a fairly short lag time and a good strong ferment.