I freezed my yeast, Is it Alright?

[NzDan]

I put my bottle of started yeast in the fridge to restart later but the thermostat was way too low will the frozen yeast starter be alright?, its liquid english ale yeast 1098.

[stringy]

The best thing to do would be to defrost it and try to step it up, and see if you get any activity. Yeasties can be stubborn little buggers.

I have succesfully recovered yeast from a fridge that was far colder than it should have been, but I have never frozen it!

Let us know how you get on.

[HogieWan]

Freezing is supposed to break the cell walls and kill the yeast, but they are hardly little buggers.

[stringy]

I just meant that they can put up with more than most people realise!

I thought freezing probably wouldnt have done them much good, but hadnt realised it broke the cell walls!

[stronk]

Well, yes and no. Quick freezing is better than slow (although yours will have been slow, unfortunately), because the crystal size is kept under control. Many cell membranes will break even with a quick freeze, but you will usually have cells which survive.

Yeast is a whole different kettle of fish to your standard animal or plant cell, though, because it can produce spores and live in effectively suspended animation for quite a while (I think I'm right here :)). That's why you can dehydrate it completely and it revives just fine, even after years.

In other words, I have nothing to add to the above posts except my opinion that it will be fine after a bit of starting.

[HogieWan]

Originally posted by stronk

In other words, I have nothing to add to the above posts except my opinion that it will be fine after a bit of starting.

I agree - make a small starter and step it up a couple times.

[NzDan]

Topped it up with dme about 3am last night after it had defrosted, by 9am it was bubbling away ferociously, so i guess it survived it, if its bubbling its gotta be good huh.

What do you mean by stepping it up a couple of times, I just emptied most of the existing starter wort and boiled 1 cup dme in 1 litre of water and added that to the yeast cake on the bottom, shook it up and put the airlock on,

Should i do this twice?

[HogieWan]

If it's going that wuick, I wouldn't worry about stepping up again.