I received a pack of Wyeast American Ale yesterday and popped it into the back of my fridge only to find this morning that it may have partially turned slushy from the (evidently) colder area in the back of the fridge. It definitely wasn't frozen solid, but I could hear a slushy mixture inside. I immediately pulled it out and moved it to another area that I know won't be as cold. I would estimate the duration of time in the fridge was about 18-20 hours (but that time would include chilling from ambient temperature.

Have I damaged the yeast beyond repair? Is the only way to determine the effect to smack it prior to brewing to see if it swells properly? Any recommendations on a course of action in either case? Should I go ahead and pitch another pack to be sure or is that overkill?


  • Are you sure the stuff actually froze a bit? Smack packs sounds pretty "slushy" anyway.
    – brewchez
    Commented Aug 22, 2011 at 11:07

2 Answers 2


Some of the yeast probably died when they were frozen, but you still might have enough to pitch. I would make a starter with what you have to proof it. Throw it in a liter of water with 1 cup of dry malt extract, well aerated. If it froths or bubbles pretty soon after you are still good. You can also check out John Palmer's page on making starters, useful information.

  • 3
    Better starter info can be found at mrmalty.com. You;re better off weighing the DME for a starter than measuring it by volume. You want your starter to be in the 1.030-35 range, which you can do by using .75 oz. DME/1 cup of water. Other than that amplification, good answer!
    – Denny Conn
    Commented Aug 21, 2011 at 16:33

Smack the pack and find out. Thats the best part of the smack pack is the viability indicator of a swelling pack. If it takes a long time to swell up then you probably had significant cell damage.

Be prepared to make a starter (100g DME/1L of water) as a back-up. Although the best beers are made using a starter so maybe this is the push required to start doing starters regularly.

  • Good suggestion @brewchez. Especially part about pushing me towards using making starters.
    – Bill Craun
    Commented Aug 27, 2011 at 19:57
  • Did a starter and yeast was fine at pitching. Very vigorous blow off, in fact.
    – Bill Craun
    Commented Sep 17, 2011 at 22:55

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