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General Category => Yeast and Fermentation => Topic started by: hallowed on January 05, 2010, 03:06:30 am

Title: Frozen yeast
Post by: hallowed on January 05, 2010, 03:06:30 am
I don't have a LHBS, so I have to get everything mail ordered... I recently got in my ingredients for three batches, which were delivered early in the morning and found on my way out the door to work... I hadn't had any coffee or Mt. Dew yet, and I guess I was just in a hurry and had my head stuffed up my rear, but I somehow ended up putting my hops in the refrigerator and my yeast in the freezer........ oops. It is a smack pack of Wyeast Belgian Strong Ale and a vial of White Labs Dry English Ale.

I got home, realized what I had done, set the yeast out to thaw, and stuck it back in the fridge when it wasn't frozen anymore. I've read about people keeping their yeast slants under ice, but I'm wondering if I've screwed both cultures... I was planning on making starters for both anyhow, and if they take off then great. But should I go ahead and order more yeast, just in case? Has anyone had experience with reviving frozen yeast? I think I read somewhere that freezing for a short period of time will only kill off about 10% of the cells, which isn't a problem since I'm making a starter, but I don't have any first hand experience with this or know anyone who does....

Thanks in advance!
Title: Re: Frozen yeast
Post by: majorvices on January 05, 2010, 06:46:58 am
The ice crystals in the water actually will kill off a large percentage of the yeast - hard to say how much. You will probably want to start them in a small starter and step them up. Be prepared for the worst, though.
Title: Re: Frozen yeast
Post by: ndcube on January 05, 2010, 08:39:56 am
I had a smackpack of 3787 come in frozen during a very cold week last year.  I put it in a starter (less than a liter IIRC) and it was going strong within 12 hours.  Try it and find out.

Oh yeah, I slowly thawed it out in the fridge first if that made a difference.
Title: Re: Frozen yeast
Post by: beersk on January 05, 2010, 09:08:01 am
The cold worries me when getting smackpacks shipped from MidWest.  I don't get the insulated packaging they offer to put yeast in, but when it's sub-zero temps outside, I'm worried my yeast will freeze.  Bloody weather...
Title: Re: Frozen yeast
Post by: Thirsty_Monk on January 05, 2010, 09:21:48 am
The ice crystals in the water actually will kill off a large percentage of the yeast - hard to say how much. You will probably want to start them in a small starter and step them up. Be prepared for the worst, though.
I heard that one freezing cycle will kill 10% of yeast cells.
So give yorself plenty of time and make 2 step starter.
First step 500 ml of 1020-1030 wort and second step 2000 ml for ales and 4000 ml for lagers of 1040 wort for 5 gal batch.
Title: Re: Frozen yeast
Post by: seajellie on January 05, 2010, 07:45:19 pm
Last year a Wyeast smack pack sat in a UPS van a mere 15 miles from my house during a frigid weekend. Frustrating... almost made me turn to a life of crime. On Monday afternoon the package arrived and although the smack pack was not frozen completely solid at the time, it was 90% frozen and it could've frozen solid during the weekend. It could've warmed up some during morning deliveries.

Anywho, I went ahead and made a starter which took off fine, and subsequently used this strain in four consecutive beers. The first three turned out wonderful. The fourth, not so good. And most importantly, the beers did not age well. I'm used to getting a good year or more from my bottled beer if they are kept in the 48 to 62 degree range in the cellar, but by eight months most of these beers had turned into gushers. So, I'd suggest doing the starter and keeping those boyz cold when finished!
Title: Re: Frozen yeast
Post by: hallowed on January 13, 2010, 09:46:24 pm
As a follow-up for everyone, I made a starter with the smack pack of wyeast 1338 on Saturday, and brewed a tripel yesterday. The starter did fine, and I pitched the entire contents into the wort and had fermentation within 8 hours. So a short freezing doesn't kill off enough yeast to prevent brewing, as long as a starter is made. I'm more worried about the white labs yeast, since it's suspended in liquid more than the wyeast is. I'll let you all know how that one goes when I get to brewing with it in a week or two. Thanks to everyone who replied to my concerns!
Title: Re: Frozen yeast
Post by: seajellie on January 16, 2010, 08:36:49 am
Hallowed, that's great, thanks for the follow up, and good luck with that brew.

I may have this frozen yeast issue again in the future due to winter deliveries, so another data point 'tis good!

I should clarify my previous post. Although the "gushers" I experienced could have been due (of course) to a wild yeast infection, for various reasons I'm suspicious that was the cause. Instead, I'm thinking the gushers could be due to (as a bilogist might say) natural selection due to a bottleneck event. No not the bottleneck I drank them from, but rather the fact that one might think that a large portion of the yeast died off during a weekend spent in ice. The ones that survived could have been merely lucky, or perhaps they had some "special" genetics/characteristics that enabled them to survive in harsh conditions.

It's interesting to note (that I've heard from pros) that priming for bottle conditioning tends to "awaken" the native yeast, and can result in them consuming not only the priming sugar but also some of the residuals, resulting in a dryer beer. Not sayin' this results in a gusher, mind you, just a related and possibly intertwined topic after a possible genetic mutation. Any biochemists and yeast specialists... I would be interested to know if the genetics of a wyeast pack could possibly drift so far so quickly, given such a drastic event that might kill off 95% of the yeast?

Anyway, that's more or less why cold storage of your finished beer could be especially good in this case.