Author Topic: Yeast Freezing/Storage  (Read 1506 times)

Offline IMperry9

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Yeast Freezing/Storage
« on: December 21, 2015, 01:49:36 AM »
Hello again I hope everyone is having a good holiday and brewing season. I have made 4 brews in the last month so my winter has been off to a good start. I have been trying to really hone my brewing skills and have been focusing on yeast lately. I just made my first starter for beer the other week and just harvested/washed yeast from my last two batches. I was just curious to see if this idea I had would work.

If I was to sterilize my empty white labs yeast vials, could reuse them to store yeast in the freezer?
After browsing around the internet I have sort of come up with a method to doing so but don't know if it feasible.
1.) Boil the vials(not the caps because I read that they loose their ability to seal) to sanitize them.
2.) Take yeast in mason jars(Washed from previous batch) and decant 80% of the liquid leaving mostly yeast.
3.) Add glycerin a small percentage add it to the vial then dump in the remaining yeast from the mason jar.
4.) Then seal the vials using tape to further seal it store in the fridge for a few days to cause the yeast to go dormant then move to the Freezer(Read storing in the fridge helps the yeast keep viability).

Do you guys/gals think this would be possible or feasible to do and how long do you think the yeast would last?
EDIT: Just adding the ratio of yeast to water to Glycerin would be 2:1:1. Here are some links of how I started to come up with the idea.
http://www.homebrewtalk.com/showthread.php?t=319592
http://www.homebrewtalk.com/showthread.php?t=35891
« Last Edit: December 21, 2015, 01:53:04 AM by IMperry9 »
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Offline klickitat jim

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Re: Yeast Freezing/Storage
« Reply #1 on: December 21, 2015, 02:29:41 AM »
The benefit to freezing that I see is if you store a pitchable amount, at least enough to pitch to a starter. I dug in and had figured out a plan. 70/30 mixture of water/glycerine,  mixed 50/50 with yeast slurry to come up with a 15% glycerine storage. Unless your freezer is manual defrost, you have to store it in the frost free freezer inside a good cooler with ice packs to protect your samples from the defrost cycle.

I might try it just for fun to see if it works. I think it will as others have done it. But after considering all angles I decided to just start plating and storing on slants.

Offline stpug

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Re: Yeast Freezing/Storage
« Reply #2 on: December 21, 2015, 02:30:56 AM »

Offline IMperry9

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Re: Yeast Freezing/Storage
« Reply #3 on: December 21, 2015, 02:56:37 AM »
Thanks for the feedback I have been reading those articles and they somewhat helped spark this idea. At this time however I don't want to spend the money/time to dive fully into yeast plating/slanting. At some point I would like too but now is not that time. The reason I tried to come up with a quicker/cheaper method is for exactly that reason. I think just for fun I will try my purposed method. I definitely will follow the protocol of using a cooler and ice packs in the fridge  to maintain constant temp. My goal is to see if I can store harvested yeast for long periods(over 6 months) and still produce a viable starter while saving myself shelf space. Personally I don't think I would enjoy having multistep starters to make the yeast pitchable from such small amounts.
A fine beer may be judged with only one sip, but it's better to be thoroughly sure.
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Re: Yeast Freezing/Storage
« Reply #4 on: December 21, 2015, 03:12:24 AM »
Having "canned" wort on hand takes part of the hassle out of multi-step starters. 

Offline klickitat jim

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Re: Yeast Freezing/Storage
« Reply #5 on: December 21, 2015, 03:23:31 AM »
Cost wise, I just spent under $100 for everything I will need. A dozen phenol screw cap tubes, 10 sterile plates, two loops, 100g agar, an alcohol lamp, and a couple small flasks for step propagation.

Not trying to talk you out of it, but its not as spendy as I used to imagine.

Mark, your right about having pre-canned wort handy. I'll be adding half pint sized pre-canned to my supplies.

Out of curiously, do the screw cap tubes handle the vacuum of autoclaving 10ml of wort in them and tightening the cap while still hot? I like the idea of making a couple tubes up when autoclaving the slants. Then they are ready for inoculation with a single. But it seems like tightening the cap when they are still hot... the tubes might not hold up to the vacuum.
« Last Edit: December 21, 2015, 03:28:44 AM by klickitat jim »

Offline IMperry9

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Re: Yeast Freezing/Storage
« Reply #6 on: December 21, 2015, 03:30:56 AM »
Just curious how long does "canned wort" last? I'm assuming you made from DME and just stored in the fridge???
A fine beer may be judged with only one sip, but it's better to be thoroughly sure.
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Offline klickitat jim

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Re: Yeast Freezing/Storage
« Reply #7 on: December 21, 2015, 03:38:16 AM »
Just curious how long does "canned wort" last? I'm assuming you made from DME and just stored in the fridge???
No fridge. On a shelf in our hobby room. I'm guessing it will last until the seal rots off or the lid rusts out. Easily over a year, just like any other canned goods. I actually just canned a gallon tonight, waiting for the pressure to drop on my cooker right now.

Offline IMperry9

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Re: Yeast Freezing/Storage
« Reply #8 on: December 21, 2015, 03:55:54 AM »
Interesting I will have to try this, I haven't heard of people doing this before. This would make yeast starter days that much quicker.
A fine beer may be judged with only one sip, but it's better to be thoroughly sure.
Kegged/Bottled: N/A
Coming up:
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Chocolate Rye Stout
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Offline klickitat jim

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Re: Yeast Freezing/Storage
« Reply #9 on: December 21, 2015, 04:17:28 AM »
I use 1/2 gallon jars but not filled all the way. About 1500ml water, 100g extra light DME, and a pinch of nutrients.  Stirred well. Tighten lid bands just barely finger tight. Just enough to hold the lid in place. Then 15 min at 15psi in the pressure cooker. When its done, let the pressure cooker cool on its own. Never ever pull the rattle weight to let off pressure. Once the jars have cooled and sealed I give them a little shake to knock the break material loose and it settles to the bottom.

I make 1000ml - 1200ml starters normally. 1500ml in the jar means I can pour off enough to my starter while leaving the break in the jar.


Offline charles1968

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Re: Yeast Freezing/Storage
« Reply #10 on: December 21, 2015, 04:52:07 PM »
My goal is to see if I can store harvested yeast for long periods(over 6 months) and still produce a viable starter while saving myself shelf space.

You can store slurry in sanitised White Labs vials in a fridge for well over 6 months and make starters without problem. No need to freeze.

Offline charles1968

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Re: Yeast Freezing/Storage
« Reply #11 on: December 21, 2015, 05:00:15 PM »
I use 1/2 gallon jars but not filled all the way. About 1500ml water, 100g extra light DME, and a pinch of nutrients.  Stirred well. Tighten lid bands just barely finger tight. Just enough to hold the lid in place. Then 15 min at 15psi in the pressure cooker. When its done, let the pressure cooker cool on its own. Never ever pull the rattle weight to let off pressure. Once the jars have cooled and sealed I give them a little shake to knock the break material loose and it settles to the bottom.

I make 1000ml - 1200ml starters normally. 1500ml in the jar means I can pour off enough to my starter while leaving the break in the jar.



You also sterilised the oxygen in the air space when you boiled, so you can aerate without contaminating the starter with airborne wild yeast/bacteria - really useful trick. I use this method to prepare wort before harvesting yeast from bottle conditioned beers (though not with a pressure cooker). Viability can be low in samples from bottles so I don't like to aerate with non-sterile air and then unintentionally multiply contaminants while the few viable yeast cells are coaxed slowly back into life. But leave a bit more air in the jar - at least 50%. Shake really well before breaking the seal. Then use foil rather than airlock so more O2 can diffuse in.
« Last Edit: December 21, 2015, 05:09:36 PM by charles1968 »

Offline klickitat jim

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Re: Yeast Freezing/Storage
« Reply #12 on: December 21, 2015, 06:01:41 PM »
I always thought that after 250F 121 C for 15 minutes, plus the vacuum, that there is nearly zero oxygen in the sealed jar. In any event, I always oxygenate with O2 through a stainless sintered stone.

Offline charles1968

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Re: Yeast Freezing/Storage
« Reply #13 on: December 21, 2015, 08:07:23 PM »
Any oxygen in the jar before you boil is still there afterwards. Boiling drives oxygen out of solution but not out of the jar.

I haven't used a stone but if that produces sterile O2 then you don't need to use heat to sanitise air. Still a good trick for those of us who don't aerate with a stone.

Offline klickitat jim

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Re: Yeast Freezing/Storage
« Reply #14 on: December 21, 2015, 11:18:48 PM »
Strange, thats backwards from everything ive read about it. The lids are loose in the presure cooker because the air in the headspace expands and vents out. All of the air is vented out and replaced with steam until it reaches enough pressure to close the vent, then pressure increases to 15psi where it gently vents enough to maintain 15psi. As it cools a vacuum in created and the lids seal. Usually most of my lids are sealed before the kettle reaches ambient pressure. The rest snap seal a second or two after I remove the lid. In reality they are all sealed before they snap, they just haven't snapped yet. Otherwise if they weren't sealed, there'd be no snap of the lid...

I've never measured disolved oxygen in my canned goods, so for all I know you're right. Its just news to me.