Author Topic: Oh Crap - killed all of my yeast with a stir paddle?  (Read 1508 times)

Offline DaveJB

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Oh Crap - killed all of my yeast with a stir paddle?
« on: March 13, 2016, 08:56:22 AM »
Okay, as I lay here about to go to bed I just realized something. The way I oxygenated my wort might have killed all of my yeast.

So, I have this Jaybird stainless steel stir paddle that I love since I can use it for so many things. It has many very sharp edges. But tonight I did something I'd never tried before. Usually I oxygenate the wort by running this paddle attached to my drill motor VERY vigorously for a couple minutes. But this time I pitched the yeast first. Before you think I'm nuts I just read that one way to rupture yeast cells is by using a blender.

So, what do you guys think? 
UPDATE:
1. I had rehydrated this yeast exactly as Fermentis says to. US-05 btw.
2. OG was 1.050, 5 gallon batch of pale ale.
3. This is the paddle: http://www.norcalbrewingsolutions.com/store/Brewing_Paddle_Ultimate_Whirlpool_Paddle.html


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« Last Edit: March 13, 2016, 06:19:34 PM by DaveJB »

Offline klickitat jim

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #1 on: March 13, 2016, 09:13:12 AM »
I think its not a best practice but it ought to still make beer.

Offline DaveJB

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #2 on: March 13, 2016, 09:31:56 AM »
Oh man, after posting this I saw the talk about shear stress from stir bars! This paddle is more like a blender compared to a little round edged stir bar.

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Offline klickitat jim

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #3 on: March 13, 2016, 09:39:46 AM »
What yeast did you use? Starter?


Never mind, saw your edit. A packet of us05 has a ton of cells. I doubt you killed them all.
« Last Edit: March 13, 2016, 09:41:25 AM by klickitat jim »

Offline brewinhard

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #4 on: March 13, 2016, 12:09:20 PM »
You will be fine. Yeast are pretty tough, adaptable microorganisms. Keep us posted as to how your fermentation progresses. I will be curious to hear if you had an "abnormally" long lag time, even if.

Offline denny

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #5 on: March 13, 2016, 04:13:07 PM »
You are worrying about nothing.
Life begins at 60.....1.060, that is!

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Offline majorvices

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #6 on: March 18, 2016, 01:53:51 PM »
You are worrying about nothing.

+1. There's no way you even killed a fraction of your yeast. nAnd the shear stress from stir bars thing is completely overblown.

Offline HoosierBrew

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #7 on: March 18, 2016, 02:05:26 PM »
Agreed with all the others- you're definitely worrying too much. RDWHAHB.
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Offline salcedo

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #8 on: March 18, 2016, 02:12:23 PM »
Any updates? Fermentation ought to be going pretty strong by now

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Offline DaveJB

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #9 on: March 18, 2016, 11:18:20 PM »
So, has no one read about one of the methods to rupture yeast cells uses a blender? This paddle has some seriously sharp edges.

Nonetheless, I simply couldn't risk losing this batch (way too excited about it) so after starting this thread at about 2 am I decided not to take any chances and pitched another packet of US-05. This was about 6 hours after pitching the first time. It eventually took off and had plenty of activity.

As much as I'd loved to have let it sit to at least learn something from the batch I couldn't risk it.

Offline HoosierBrew

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #10 on: March 18, 2016, 11:24:28 PM »
So, has no one read about one of the methods to rupture yeast cells uses a blender? This paddle has some seriously sharp edges.


A blender has much sharper edges and there's also the whole RPM thing. I'm pretty sure you're not spinning the paddle @ 20,000+ rpm. No harm in being cautious but you're just not going to kill your yeast with a stir paddle.
Jon H.

Offline stufr67

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #11 on: March 27, 2016, 09:37:14 PM »
I pitch my starter and aerate with a  wine whip all the time.  Works great and never had an issue.

Offline crakers540

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #12 on: March 28, 2016, 02:00:08 AM »
Yeah, a drill will not have enough RPMs to create the shear forces needed to disrupt yeast cell walls.  Yeast cells are small enough they could butt slide on the edge of your paddle and think they were having fun on an amusement park ride.http://www.homebrewersassociation.org/forum/Smileys/default/shocked.gif

Offline crakers540

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #13 on: March 28, 2016, 02:01:37 AM »
dammit, still trying to figure out how to post an emoge

Offline klickitat jim

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Re: Oh Crap - killed all of my yeast with a stir paddle?
« Reply #14 on: March 28, 2016, 10:51:42 AM »
If stiring with sharp edged paddle killed all yeast, I would quit buying sanitizer