Aeration After Fermentation Has Begun

[agslax]

Is there ever a situation where it is safe to aerate your wort after fermentation has begun?

Background:
I am taking a stab at adding sugar and champagne yeast to a barleywine after fermentation begins. I have already used this aeration system from William's to aerate the wort before pitching the yeast in the primary. Now, fermenation has slowed and I am pitching 1oz of sugar a day. After adding about 6oz of sugar, the plan is to add champagne yeast as the american ale yeast will not be able to thrive in the high alcohol. The thought behind wanting to aerate at this point would be to give the new yeast some oxygen to work with. I have read that you can aerate as long as fermentation has not completed, but I have not found much on this topic to confirm when a cutoff point would be. Would the risks of adding the oxygenated off-flavor be too high to make this worth trying?

Thanks for the input

 

[maida7]

I think adding oxygen at this stage would be a very bad idea.

 

[disney7]

I have added a second dose of oxygen to my imperial stouts up to 24 hours after the initial pitch with good results. I usually shoot for 8 to 12 hours though.

I have never tried anything past 24 hours and from what I have read it would be a bad idea. From what I understand, the yeast will take up the oxygen and use it to their advantage early in the fermentation process (while the ferment is vigorous). Anything past that will probably cause oxidation and wet cardboard taste.

I see that you are adding yeast and sugar, but I would worry that the amount of sugar you are adding won't create a vigorous enough ferment to use up all the oxygen you add.

 

[agslax]

Correct, the sugar/yeast would most likely not lead to a vigorous fermentation. That might be the key.

 

[Revvy]

The only recommended situation where that is appropriate and safe is during extremely high gravity beers, within the first 12 hours. Once fermentation has begun oxygen becomes the enemy of beer, not before completed, once it's begun. As soon as you have beer in there, it is no longer a good idea.

 

[agslax]

Sounds like that answers my question. As good as it looks right not, I am not going to mess with it.

Thanks all for the responses!

 

[2bluewagons]

What american ale yeast did you use (001, 1056, US-05) and what ABV are you expecting? Beer yeast is more tolerant than most people think, I had a BW ferment out in 2 weeks to 12.5% ABV with just an initial pitch of US-05. Low mash temp, pitching rate of healthy yeast at the beginning, and a staged simple sugar addition (like you are doing) are the keys. Unless you are looking for the last few points of gravity to be shed (and even then I don't think it's necessary to use champagne yeast), you need a beer yeast if you want it to taste like beer. I say add the sugar alone and see how the yeast takes it.

As others have said, as soon as there is any alcohol in the fermenting beer, O2 is the enemy. Minimizing splashing and air contact is encouraged, so certainly using an oxygenation setup like you have is a big no-no.

Besides that, cheers to big beers

 

[agslax]

I used 1056. The tolerance there is 11%, so it technically can not take it to the goal of 12-13%. It took it a week to get 10%, so it is a very strong yeast, but I was afraid it won't be active much longer.

 

[cluckk]

It is not uncommon to aerate a high gravity ale 12 hours or so into primary.