How much air does yeast need during fermentation?

[joe7dust]

Would a shut cooler lid be good? It's not a tight seal and I read you want a little bit of oxygen to get in, but I have 0 experience in homebrewing.

 

[Inthekeg]

Joe7...There is optimal levels of oxygen and then there are all points leading up to it. I am trying to find the data for this, but it has been sooo long since I bothered with this. I do know that when I was exploring this issue it prompted me to get an oxygen stone, which I highly recommend. Having said that, I have never had a stuck fermentation that resulted from lack of oxygen when simple agitation was used. I seem to remember that yeast prefer oxygen levels at around 25 ppm. Agitation yield only about 8 ppm, but if you do it several times throughout fermentation you can compound the effect. About 20-30 second with an oxygen stone gets you there right of the bat. You'll know you have potential oxygen problems if you miss your taget gravity by too much (although this may be caused by a couple of other issues).

 

[joe7dust]

I'm shooting for .99 and I don't have a hydrometer so I was just going to let it go for the recommended time and hope for the best. The guide I have makes no mention of O2 stones or even how much O2 the fermentation vessel needs unfortunately.

 

[Edcculus]

Oxygenate the wort before you pitch. Put on an airlock after you pitch and don't let oxygen in. I hope this makes sense. Its 2am!

 

[david_42]

Yeast only needs oxygen during the growth phase. Fermentation doesn't start until the oxygen is gone. If you keep adding oxygen, you'll end up with a huge amount of yeast and little else.

 

[Edcculus]

Yeast only needs oxygen during the growth phase. Fermentation doesn't start until the oxygen is gone. If you keep adding oxygen, you'll end up with a huge amount of yeast and little else.

I think thats the point I was trying to get across last night when I decided to answer the question after a heavy night of drinking.

Note to self, dont try to answer technical questions when drunk. Go straight to the drunken ramblings forum.

 

[joe7dust]

So will I run into problems if I just have a shut cooler lid? Not going to be completely airtight.

 

[Edcculus]

No problems.

 

[Hammer]

I'm shooting for .99 and I don't have a hydrometer so I was just going to let it go for the recommended time and hope for the best. The guide I have makes no mention of O2 stones or even how much O2 the fermentation vessel needs unfortunately.

Nothing wrong with your technique, but if you get a .99 FG, be sure to let us know. Beer doesn't finish that low as a rule.

To your original Q, if you can aerate the wort the best you can at first, you (and your yeasty buddies) will be fine. Once they get to turning sugar into alcohol, they are done multiplying and into consuming. I wouldn't stuff that cooler lid on tight- it might pop off and make a mess....

 

[Yuri_Rage]

What, exactly, are you fermenting, and what, exactly are you fermenting it in?

 

[ChshreCat]

He's fermenting a bunch of sugar in water using superyeast and then planning on using it to spike some Hawaiian Punch. Hopeing for 20%+ abv. I think the OP has been shown the door.

 

[gplutt]

He's fermenting a bunch of sugar in water using superyeast and then planning on using it to spike some Hawaiian Punch. Hopeing for 20%+ abv. I think the OP has been shown the door.

You saw this, too? CANOE -- CNEWS - Canada: High-test homebrew fuelling violence

 

[jpowers1]

I've heard the super yeast tastes bad. I have no experience with it, but this has been the main point of detractors.