How many of you oxygenate dry yeast?

[BlitzkrausenNate]

Hey all,
Of those of you that use dry yeast, do you you oxygenate? I've been using more dry yeast as of late for it's ease of use, and have been using my diffusion stone but this might be in vain since the manufacturer puts lipids in dry yeast to allow for 3x growth. Was wondering if anybody had any input. Thanks in advance.

 

[Craigmn]

I do because it doesn't hurt at worst.


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[pvpeacock]

I do. It's like wearing a belt and suspenders. It can't hurt.

 

[rlonardo]

Also like a belt, it completes the outfit!

I would think the yeast still need the oxygen to grow.

 

[Brewenstein]

Although supposedly not necessary, I hit for 30 sec. with O2. Figure it can't hurt. When I re-pitch yeast I go for 60 sec.

 

[jcp]

Regardless of whether I'm using dry or liquid yeast, I still shake my fermenter for 5 minutes to oxygenate. There's no way anyone can convince me that dry yeast has some magical ability to not-need oxygen (unless you can convince me, in which case I will be convinced).

 

[BlitzkrausenNate]

Thanks dudes, I think I will just continue giving it a quick shot of O2. Anything that will help the yeast to be happy and healthy is good. Using the diffusion stone is kinda badass anyway

 

[MaxStout]

I use O2 with a stone right before pitching--regardless if it's dry or liquid yeast. Why not give the little critters every possible advantage?

 

[day_trippr]

fwiw, after reading Yeast I try to hit 12ppm no matter what strain or style I'm using...

Cheers!

 

[BlitzkrausenNate]

The silly irony is that I own that book but haven't read it yet. Thump-head. I just pitched some yeast a couple hours ago and aerated and the hamster wheel started spinning.

 

[zoomzilla]

I've only use dry yeast and I just got an oxygen wand. Haven't tasted any of the beers yet but the yeast cake on all of them is 5 to 10 times larger than anything I've ever seen. That can only be a good thing.

 

[wingedcoyote]

I do my four minute shake rattle and roll aeration whether I'm using liquid or dry yeast. Why? Mostly because it's habit and I'm usually most of the way through it before I remember that dry yeast doesn't need the oxygen.

 

[Sloobie]

One of the primary roles of oxygenation is to encourage lipid synthesis (aka sterols) which promote membrane permeability and, thus, nutrient uptake and growth. After oxygen is depleted, sterol concentration is pretty much fixed, and they are divided up during regular cell division until there are so few left that they cannot be divided and growth ceases (or other nutrient limitation occurs first).

Dried yeast is grown aerobically, meaning these important lipids (sterols) are already present in the yeast rather than, say, the lipid-depleted cells you get from the end of a fermentation.

What this means: If you oxygenate wort using dried yeast, you will allow the yeast to synthesize more sterols on top of those they already have. This means the yeast will be able to divide more, thereby producing more biomass at the expense of ethanol (and possibly more esters as well). In other words, it's just habit to oxygenate, it feels wrong not to, and it's not really doing any harm, just producing less ethanol and more yeast.

 

[Pkrd]

I usually don't. Just give a quick shake to mix in the yeast. Which I probably don't need to do either.

 

[eadavis80]

I do - throw the diffusion stone in there with the aquarium stone setup for 15-20 minutes while cooling my rehydrated dry yeast down to pitchable temps. By the time aeration is complete, yeast is good to pitch!

 

[boydster]

It's totally unnecessary as long as you are pitching enough hydrated yeast (or twice as much unhydrated). If you underpitch, the extra oxygen becomes necessary for allowing the yeast to go through the extra cell divisions.

If I'm worried that I might be on the low end of a decent pitch rate, I aerate. Usually, I try to target ~1 million cells/ml/°P for my clean ales, and in those cases I don't aerate - just hydrate and pitch.

 

[kombat]

The manufacturer's website indicates that oxygenation is unnecessary with dry yeast. That said, the only time I actually did it (pitched rehydrated US-05 into wort that had not been aerated in the slightest), I ended up with the biggest banana-bomb I've ever tasted. So now I aerate all my worts, regardless of whether I'm pitching liquid yeast or rehydrated dry yeast. I whip up a nice foamy head with a Fizz-X degassing rod on a drill for a couple of minutes, then pour in the yeast.

 

[BlitzkrausenNate]

One of the primary roles of oxygenation is to encourage lipid synthesis (aka sterols) which promote membrane permeability and, thus, nutrient uptake and growth. After oxygen is depleted, sterol concentration is pretty much fixed, and they are divided up during regular cell division until there are so few left that they cannot be divided and growth ceases (or other nutrient limitation occurs first).

Dried yeast is grown aerobically, meaning these important lipids (sterols) are already present in the yeast rather than, say, the lipid-depleted cells you get from the end of a fermentation.

What this means: If you oxygenate wort using dried yeast, you will allow the yeast to synthesize more sterols on top of those they already have. This means the yeast will be able to divide more, thereby producing more biomass at the expense of ethanol (and possibly more esters as well). In other words, it's just habit to oxygenate, it feels wrong not to, and it's not really doing any harm, just producing less ethanol and more yeast.

Thanks Sloobie! I much appreciate everyone's feedback, but Sloobie, you hit it out of the park! That's just the type of info I wanted. It sounds like you have a solid yeast background. Thanks to all who have replied

 

[NathPowe]

Thought I'd chime in as well. I've been using liquid lately, but had been using dry almost exclusively before that. I always oxygenated with pure O2 before pitching rehydrated dry yeast. As has been said already - what can it hurt?

Good luck on your brew. Cheers.

 

[BlitzkrausenNate]

The manufacturer's website indicates that oxygenation is unnecessary with dry yeast. That said, the only time I actually did it (pitched rehydrated US-05 into wort that had not been aerated in the slightest), I ended up with the biggest banana-bomb I've ever tasted. So now I aerate all my worts, regardless of whether I'm pitching liquid yeast or rehydrated dry yeast. I whip up a nice foamy head with a Fizz-X degassing rod on a drill for a couple of minutes, then pour in the yeast.

I have also read that it is unnecessary by the manufacturer but I don't think it's a black and white issue as well. I have had homebrews over the years that have had certain amounts of esters that I couldn't right off as too high high of fermentation temp since I have a temp controller, that I wondered might be from too low count/weakened yeast.

I usually hydrate my yeast and then immediately put it in the fridge with a saran wrap cover to bring it down to close to ambient wort temps to avoid shock. (I didnt rehydrate last night due to low OG and laziness) Like you, I used to use a degassing bit on a corded drill to whip gas into suspension. I recently have purchased an oxygenation stone from Midwest homebrewing that works off the small O2 tanks from hardware stores. The tanks are about $10 here in Boise, so they are pricey, but it sure is easy and it doesn't take much to just spray the wand with Star-san and give a swirl in the wort for a minute.

I read this short article on yeast yesterday from Dr. Clayton Cone (I think he works for Danstar/Lallemand) and thought it really got down to the "brass tacks" of yeast techniques and was a good read:

http://koehlerbeer.wordpress.com/2008/06/07/rehydrating-dry-yeast-with-dr-clayton-cone/

 

[ncbrewer]

I've been aerating when using dry yeast, but I recently picked up an infection even though I thought my cleaning and sanitation were good. Now I'm considering skipping the aeration in order to minimize exposure to the air. It's possible that some dust from the grain is still around and some can get into the fermenter.