Dry Yeast Oxygen Requirements

[rkbarnes82]

So after some research I came to the conclusion that dry yeast is dried with sufficient sterol reserves to multiply enough times and properly ferment the wort without additional aeration or oxygen. So I brewed a 1.070 IPA and pitched 2 packs of rehydrated packs of US05. Everything went well but I can't help to be nervous that I'm gonna end up with a stuck fermentation. Am I needlessly worrying? My goal was to minimize staling.

 

[boydster]

You should be just fine. A little oxygen doesn't hurt when you pitch, but as you stated, they are packaged with enough sterols for a full fermentation as long as you had a good pitch rate (sounds like you pitched plenty of cells). Did you rehydrate the yeast? That has a big impact on the total viable cells pitched.

 

[dangerbrew]

I'd say you should be totally fine, and I would also say on top of that to NOT worry about the staling in terms of aeration in the beginning.

One of my good friends who is the assistant brewer at our local brewpub and who also brews really great homebrew shakes the HELL out of his beer before pitching his yeast and never has problems - heck, he even shakes the hell out of it afterwards too to rouse it occasionally, and I've never noticed any oxidation or anything like stale/cardboard flavors in his beers, many of which have won local competitions.

Another local professional brewer that I am friends with sometimes has a difficult time getting his fermentations off to a good start even though he makes really large starters for his beers, and I attribute it to his lack of aeration going into the fermenter. Myself, I fill my carboys directly from the pump hose coming out of the boil kettle and it basically shoots down into the carboy really fast and makes a lot of foam and get a ton of oxygen injected into it by doing this. That said, my yeast starts up QUICK and I have really good vigorous fermentations because of it that finish up totally in about 5-6 days max.

So yeah. Don't be afraid to shake it, shake it, shake it like a polaroid picture. IMO it seems to help a lot actually.

 

[TipsyDragon]

Anyone else think 2 packets of dry yeast is overkill? Where these 5 or 11 gram yeast packs?

Your beer will be fine. Leave it alone and let the yeast do their thing.

 

[rkbarnes82]

I wasn't concerned with stalling but staling or in other words oxidation or a rapid loss of hop aroma/flavor.

I ran it through mr malty and it said to pitch 1.4 packets, I figured an even 2 would help ensure not a lot of growth was needed, given my concern. They were 11gram satchets.

 

[rkbarnes82]

I wasn't concerned with stalling but staling or in other words oxidation or a rapid loss of hop aroma/flavor.

I ran it through mr malty and it said to pitch 1.4 packets, I figured an even 2 would help ensure not a lot of growth was needed, given my concern. They were 11gram satchets.

Edit: just reread your post on "staling", disregard my response.

 

[TipsyDragon]

You only needed 12 grams of dry yeast, according to mr malty iPhone app. But in any case it's to late now. As long as you don't pop the top on the carboy shake it all you want. You can't oxidize your beer if there is no oxygen in the headspace of your carboy.

For my beers I've used aquarium aerators or pure O2 through an 5 micron air stone. I have found that smaller holes in the stone are better at preventing foam in your carboy. Both are cheap and work better than shaking alone.

PS. Isn't autocorrect a pain in the butt sometimes.

 

[BigFloyd]

Anyone else think 2 packets of dry yeast is overkill?

Nope, especially if he didn't rehydrate it. One 11g packet rehydrated is good for an ale up to 1.060 according to Mr. Malty calc. The OP's wort was at 1.070. He probably would have been OK with a single packet rehydrated, but he didn't over-pitch enough to cause any problems

Re: aeration using dry yeast question, no worries there. Those dry cells are packaged with sterols to provide sufficient O2 through the initial (aerobic) stages of fermentation.

I'm rigged to bubble bottled O2 through a 0.5 micron stone and do so religiously when using liquid yeast (especially in lagers), but when pitching rehydrated dry yeast I just do some simple aeration by cracking the pump outlet valve full open when recirculating back into the kettle at the end of chilling.

 

[rkbarnes82]

I normally pump pure O2 through a stone. I've notice maybe my hoppy beers are fading fairly quickly or maybe oxidized. So I figured this time I would try this technique.

And my batch size is about 6-6.25

 

[TipsyDragon]

He probably would have been OK with a single packet rehydrated, but he didn't over-pitch enough to cause any problems

Agreed.