accidentally froze my starter!

i'm planning on brewing an AHS Hopslam clone tomorrow and i made a 2.3L starter with WLP001. after 24hrs on the stir plate, i went to stick it in the freezer for a short time to get the yeast to drop out. well, i got distracted and had to hurry into work. about 6hrs later i remembered. it was pretty much frozen solid.

i've read that freezing only drops viability by about 10%, so it should still be good after it thaws out right? or will it be necessary to decant once thawed and make a new starter? i'm really pushed for time and i need to use this tomorrow (later today actually) if i can.

When people freeze yeast they add glycerine or other additives to keep the ice crystals from rupturing the cell walls. I've never frozen yeast in just water before, so I don't know how well they would fare. My guess is that the viability has gone way down and you'll have to make another starter, but I'm not sure. Maybe someone who knows more about it than me can chime in.

lpdb185 said:

i've read that freezing only drops viability by about 10%

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I seem to remember Chris White saying that on the BN, but definitely thaw it in the fridge, decant the beer, and throw some fresh wort on the cake. Just a little wort will proof the yeast and you won't have to wait for it to finish out.

Have some US-05 or Notty around for backup.....

944play said:

Have some US-05 or Notty around for backup.....

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i had actually intended to get some nottingham when i ordered this, but i forgot to add it to my cart. that's just how my luck goes.

what will it hurt if i pitch this, it doesn't take off, and it has to sit for 3 days until i get fresh yeast? i'm just not going to have the time to brew for at least another week and a half to two weeks.

+1 for thawing, decanting and adding fresh wort

I did this last weekend with WLP830 (German lager). My temperature probe on my freezer accidentally fell out and frozemy 2 L starter. I defrosted it, decanted, added the yeast to another 1 L of wort that I had for a back up. I had visible signs of fermentation in the yeast starter within an hour. RDWHAHB.

Frozen bread dough rises after thawing.

well, my history of luck in brewing says it wont work. but, i thawed it out and sphoned off the old wort, then i added the yeast to another small starter. it'll be on the stir plate for 4-5hrs and then i'll pitch it. we'll see if it works.

jgln said:

Frozen bread dough rises after thawing.

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But bread dough is not water. From another thread the logic is that Ice crystals act as knives and rupture the cell walls.

william_shakes_beer said:

From another thread the logic is that Ice crystals act as knives and rupture the cell walls.

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This is correct. That is why frozen meat and fruit has a different texture than fresh(as well as bleeding more). The water molecules form together to make ice crystals. The slower the freezing, the rougher and larger the ice crystals and the more ruptured cells you have.

EDIT: quote fail.