Frozen Yeast advice

Ingredients
1

One of the risks of ordering yeast online where I live is that we can see days with highs in the -10s F.

I received a package of Wyeast 1007 that was nearly frozen solid (my fault).  It was still a little slushy, similar in consistency to an orange juice concentrate. :-\

I slowly thawed it out in a fridge, then to room temp.  I smacked it and when I checked back 4 hrs later it was swollen.  Not tight but nearly full.  This seemed promising.  (fyi:  The customer support rep I spoke with at MoreBeer thought the yeast would be dead.  Wyeast’s website recommended using the yeast if the pack swelled.)

I then pitched to a 1000 ml starter with stir plate and when I checked about 8 hrs later it looked milky and active.  The krausen was overflowing the flask even while stirring.

Everything looks good.

My question:

Should I be concerned that the freezing may have damaged this yeast?
Or am I good to go now that I see signs of healthy yeast activity?

I plan to step up one more time before pitching to a 2000 ml starter prior to brewing.

Any suggestions or feedback is appreciated!

Cheers,
Tyler

2

I wouldn’t worry after the starter took off like that. That shows yeast health, which is arguably more important than the cell count.

3

And with healthy yeast, in each starter step you will tend to grow the count up to the maximum supported by that volume,  so you should end up where you wanted to be.

4

Thank you for the feedback!

I pitched the 2nd step 1800 ml starter into 5 gallons of 1.050 wort.  I’ll try to remember to update as the beer matures.

Cheers!

5

There may be up to a 10% viability loss for each freeze thaw cycle according to Wyeast.

6

I had a completely  frozen batch of washed Bavarian lager yeast.  After reading this post i decided to stay the course warm gently  and try to get going in a starter adding a little corn sugar  solution. I was worried after no activity 12 hours after pitching but 24 hours after and I have decent airlock activity.  My experience was a delayed activity but still survived to pitch just fine.