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Frozen Yeast?

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bobo1898

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Have a variety of yeast in my fridge that's in the garage--harvested from previous batches and one that is a spontaneous wild strain.

Chicago has seen some bitterly cold days around Christmas and the early part of the New Year. Because of this, I haven't been dealing much with any brewing. The other week I noticed that the beer/water that rests above the settled yeast was complete ice in some of my jars. We were reaching 20 and 30 below during some nights with the windchill.

I've read in some places that when you freeze yeast (without proper care), a large percentage of the cells die. I suppose I'm more concerned with my wild strain than the rest, but some of these were 4th, 5th, and 6th generations. Obviously would suck to lose them.

My best bet to try and step them all up? Just want to get an idea of how bad this is for the yeast.
 
That's what I would do. Proof them with small low gravity starters (1.020 to 1.030). Any that perform well you can step up. In the future you might think of keeping some glycerin on hand.
 
bobo1898 said:
Have a variety of yeast in my fridge that's in the garage--harvested from previous batches and one that is a spontaneous wild strain.

Chicago has seen some bitterly cold days around Christmas and the early part of the New Year. Because of this, I haven't been dealing much with any brewing. The other week I noticed that the beer/water that rests above the settled yeast was complete ice in some of my jars. We were reaching 20 and 30 below during some nights with the windchill.

I've read in some places that when you freeze yeast (without proper care), a large percentage of the cells die. I suppose I'm more concerned with my wild strain than the rest, but some of these were 4th, 5th, and 6th generations. Obviously would suck to lose them.

My best bet to try and step them all up? Just want to get an idea of how bad this is for the yeast.
Click to expand...

Man that's awful that the temps are getting to your yeast, as you said just grow then back up and get more cells and store them properly. With luck you can save some of them
 
Follow BOB357's advice!  Freezing temperatures forces yeast cells to utilize its internal supply of sterols to try to prevent rupture of the cell walls.  You need to wake them up gently, allow the yeast to slowly come up to room temperature and then add them to a low gravity starter to allow them to rebuild their reserves.  You can then step up to a normal gravity starter from there if you see some activity.
 
Sounds great guys! Thank you all for the responses!

In the future should I always store them in the fridge with glycerin in the winter, just in case?

Primary concern is the wild strain and some of the generational yeast. If I can only save the wild strain, I'll be happy.

So we're talking 500ml to 1000ml of 1.020? There's a solid amount at the bottom.
 
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