Guide to Making a Frozen Yeast Bank

[fc36]

You can technically culture yeast from any unpasteurized beer. It's just easier when there are lots of un-filtered and/or un-flocculated yeast left in there. Apologies if this sent twice. My phone is stupid.

Here's to free pacman yeast! I'm headed to the store tonight to get my hands on some rogue and give it a whirl (Nice, a stirplate pun).

 

[Cordane]

So, question! I'm not terribly familiar (YET!) with sour bugs, but I'm considering doing a couple of sours in the near future. I was planning to get the WLP665 Flemish blend that includes all of the good stuff in one package. Can I simply use this technique to freeze the whole lot of them together the same way I would if it were a single strain? It's a platinum release, so I'd love to have it throughout the year.

 

[-MG-]

I can't find info in this thread about doing this on a larger scale.

I have no interest in only getting 10ml of yeast (10 billion cells) and then making 2-3 steps in starters just to get it to a 6 gallon batch.

I think if we were talking about say.. 50ml of yeast in a vial (what size vial?) this would be worth the time and effort.

 

[MalFet]

I can't find info in this thread about doing this on a larger scale.

I have no interest in only getting 10ml of yeast (10 billion cells) and then making 2-3 steps in starters just to get it to a 6 gallon batch.

I think if we were talking about say.. 50ml of yeast in a vial (what size vial?) this would be worth the time and effort.

I've used 50mL preforms for this. Still, plan on doing a few steps if you want to bank yeast. It's not just an issue of numbers but also viability and contamination.

 

[mthompson]

I've used 50mL preforms for this. Still, plan on doing a few steps if you want to bank yeast. It's not just an issue of numbers but also viability and contamination.

It's also an issue with space. In the space of a couple larger vials, I can have several small vials of several different strains.

You will still need to do at least one starter step, and probably two. The growth/reproduction rates of yeast in a stir plate starter will equalize any benefit of starting with more yeast. Basically, with 3 steps (an extra day essentially) and a smaller frozen aliquot I would have more healthy, viable yeast than a 2-step starter that was inoculated with a relatively larger frozen aliquot.

Also, it's important to remember viability is a proportion of the aliquot, and as such, the larger your aliquot the more non-viable yeast you will have. The law of diminishing return will dictate (theoretically) the optimal size of aliquot to store. (sounds like a good experiment for hbt yeast bankers)

MT

 

[Mobeers]

This thread is awesome. Let me get thIs straight though. I fill the vial with glycerin and water prior up to 20% prior to the yeast or just 20% glycerin and 80% yeast? Thanks!

 

[Mobeers]

Any help? I was planning on doing this today and could use the help, thanks.

 

[guldalian]

80% slurry, 20% glycerin.

 

[Mobeers]

^ thankyou!

 

[gwapogorilla]

I just tried this....it isn't working for me. I am staring at a 1 quart starter that I made 24 hours ago. Absolutely NO activity in it at all.

 

[bja]

I just tried this....it isn't working for me. I am staring at a 1 quart starter that I made 24 hours ago. Absolutely NO activity in it at all.

Maybe 24 hours isn't long enough.

BTW, what exactly did you try to do?

 

[gwapogorilla]

Maybe 24 hours isn't long enough.

BTW, what exactly did you try to do?

I washed yeast from primary ferm tank....washed it very good so I ended with 3/4 cup of THICK yeast(after it settled in the fridge for a few days).
I boiled all of my vials (8 dram glass vials from amazon), caps and tools for 10 minutes and also dunked everything in star-san as I used them.

I boiled 30 ml of glycerin and 70 ml of water together, then cooled them to 70*F. I filled a sanitized measuring glass to 40 ml with the yeast sludge, then added another 40 ml of the glycerin/water solution.(50% yeast...15% glycerin...35% water total) I stirred together and then filled my vials...almost full. Capped them closed(tight) and put them in a freezer(deep freeze NOT frost free).

After only 3 days in the freezer, I put in the fridge for 2 days to thaw out. Then into a 70*F starter with a gravity of 1.038(32 oz volume). Starter NOT on a stir plate...just a jar with wort in it. I am starring at the starter now...2 days no activity. When I try to shake it up, the yeast settle straight to the bottom in record time.

Any ideas?

 

[StMarcos]

I washed yeast from primary ferm tank....washed it very good so I ended with 3/4 cup of THICK yeast(after it settled in the fridge for a few days).
I boiled all of my vials (8 dram glass vials from amazon), caps and tools for 10 minutes and also dunked everything in star-san as I used them.

I boiled 30 ml of glycerin and 70 ml of water together, then cooled them to 70*F. I filled a sanitized measuring glass to 40 ml with the yeast sludge, then added another 40 ml of the glycerin/water solution.(50% yeast...15% glycerin...35% water total) I stirred together and then filled my vials...almost full. Capped them closed(tight) and put them in a freezer(deep freeze NOT frost free).

After only 3 days in the freezer, I put in the fridge for 2 days to thaw out. Then into a 70*F starter with a gravity of 1.038(32 oz volume). Starter NOT on a stir plate...just a jar with wort in it. I am starring at the starter now...2 days no activity. When I try to shake it up, the yeast settle straight to the bottom in record time.

Any ideas?

Try the fridge treatment before putting them in the freezer. Warm up in 80degF bath and pitch immediately.

 

[funnycreature]

Does anyone have experience with freezing yeast blends? I have been freezing all my yeast strains so far but I'm interested in trying the WLP080 Cream Ale Blend. I'm just worried that with a starter to grow the yeast I will select for one or the other strains thus changing the flavor profile.

 

[StMarcos]

I had poor luck freezing yeast, but I now know I used too much glycerin (40+%) and I chucked the vials immediately into a -20 box. Interested to start experimenting again....

 

[bja]

Does anyone have experience with freezing yeast blends? I have been freezing all my yeast strains so far but I'm interested in trying the WLP080 Cream Ale Blend. I'm just worried that with a starter to grow the yeast I will select for one or the other strains thus changing the flavor profile.

How would you do that?

 

[funnycreature]

How would you do that?

Do what? If you mean how I would select for one strain over the other, that's nothing I'd do on purpose; it's just survival of the fittest Let's say I incubate the starter at ambient temperature, which is in the high 70s right now. If the ale strain in the blend grows better at these temps than the lager strain the former will simply outgrow the latter. If I then use this starter culture for freezing I already have a blend that's of a different composition compared to the original. The only way to do this right would be to find out which strains are in the blend, grow both independently, and then mix them in the right ratio before pitching.

Now if that wasn't your question then I apologize for the lengthy reply

 

[bja]

Let's say I incubate the starter at ambient temperature, which is in the high 70s right now. If the ale strain in the blend grows better at these temps than the lager strain the former will simply outgrow the latter. If I then use this starter culture for freezing I already have a blend that's of a different composition compared to the original. The only way to do this right would be to find out which strains are in the blend, grow both independently, and then mix them in the right ratio before pitching.

Why would the ale yeast grow better than the lager yeast at such warm temps?

 

[funnycreature]

Why would the ale yeast grow better than the lager yeast at such warm temps?

I didn't say it does. It's just something that I'm afraid might happen. I'm not a yeast expert and my fears might be completely unjustified.

 

[jah777]

I froze some yeast a few months ago with about 20% glycerin per vial but I now notice that ice crystals have formed in some of the vials. Should I still try to use these or toss them?

 

[funnycreature]

I froze some yeast a few months ago with about 20% glycerin per vial but I now notice that ice crystals have formed in some of the vials. Should I still try to use these or toss them?

You won't know until you try! I'd do a "dummy" starter that you don't need for anything. If there's any yeast left it'll grow eventually.

 

[anico4704]

I also asked some of these on Brewitts article but I will report back my findings on both when I get suggestions. I have a few questions:

1.I read through many of these posts and the consensus seems to be that the glycerin has to be sterilized in the pressure cooker correct?

2.Also, it seems that the vials also need to be sterilized. How are some people using the preform bottles if this is the case? Aren't those just plastic, or are you just sanitizing those with Star San?

3.When freezing, are the ice packs ok to be wrapped around the cooler walls, or do they need to be in direct contact with the vials? I was thinking a styrofoam cooler with the alcohol ice cold packs taped to the walls, unless the have to be in direct contact with the vials?

Thanks!

 

[mredge73]

1&2; The Glycerin solution is sterilized in a pressure cooker with the vial. Most vials used are glass, some are heat resistant poly-carbonate.

I used canning jars; 1/2 pint jelly jars work great, available everywhere, and are cheap.
Solution is mixed in jar. Jar is sterilized in pressure cooker. Jar and solution remains sterilized until I open the cap to add yeast.

 

[Brewzologist]

A big thank you to FlyGuy! What follows is proof the methods he posted to freeze yeast works:

I took a new vial of White Labs Kolsch yeast, WLP029 with an original best-by date of 7/3/2012 and froze it on 4/6/2012, storing it inside a small cooler with ice packs inside a top freezer/fridge. I moved 2000 miles across the country in the fall of 2012 with this, and other yeast strains, packed in dry ice. In February 2013 my fridge broke and it was only the small cooler with ice packs that protected the yeast for about 8 hours before I was able to transfer it to a working fridge. My point is; this yeast has been subject to variations in temperature.

I used 16ml vials and filled them with 7ml of settled yeast, then added 6ml of 50/50 water/glycerin. This left 3ml of head space in each vial, and by my calculation is 23% glycerol. I used Walmart USP glycerin from the cosmetics aisle, and meticulous sterile technique with a pressure cooker, etc described in this thread, at home.

In early-July 2013 I removed a vial of this Kolsch yeast from the fridge and stepped it up a number of times. I started with a 150ml 1.020 starter, the 250, 500 and 1L starters at 1.040. In between each starter I put the yeast into the fridge to settle, then decanted the spent wort and added more each time. My starters were done on a stir plate.

Last week I took the final settled yeast and stepped it up again using a 1.5L starter at 1.040. Then on brew day I made a 500ml starter and pitched the entire starter into my 7.5 gallon batch of wort after about 12 hours on the stir plate. The OG from my refractometer was 1.054 and tonight after 6 days of fermenting I took a sample and it was at my FG target of 1.009. The beer tastes good too, albeit flat.

In short, I can say that 7ml of Kolsch yeast frozen for 15 months in a regular consumer fridge with 23% glycerol solution was successfully used to brew a 7.5 gallon batch of beer. Tonight I'm taking a vial of Denny's Favorite 50 (Wyeast 1450), that was frozen in 4/2012, and will attempt to bring it back to life too. I'll post my results with the 1450 when my next batch of beer has fermented out.

Thanks again FlyGuy!

 

[guldalian]

A big thank you to FlyGuy! What follows is proof the methods he posted to freeze yeast works:

I took a new vial of White Labs Kolsch yeast, WLP029 with an original best-by date of 7/3/2012 and froze it on 4/6/2012, storing it inside a small cooler with ice packs inside a top freezer/fridge. I moved 2000 miles across the country in the fall of 2012 with this, and other yeast strains, packed in dry ice. In February 2013 my fridge broke and it was only the small cooler with ice packs that protected the yeast for about 8 hours before I was able to transfer it to a working fridge. My point is; this yeast has been subject to variations in temperature.

I used 16ml vials and filled them with 7ml of settled yeast, then added 6ml of 50/50 water/glycerin. This left 3ml of head space in each vial, and by my calculation is 23% glycerol. I used Walmart USP glycerin from the cosmetics aisle, and meticulous sterile technique with a pressure cooker, etc described in this thread, at home.

In early-July 2013 I removed a vial of this Kolsch yeast from the fridge and stepped it up a number of times. I started with a 150ml 1.020 starter, the 250, 500 and 1L starters at 1.040. In between each starter I put the yeast into the fridge to settle, then decanted the spent wort and added more each time. My starters were done on a stir plate.

Last week I took the final settled yeast and stepped it up again using a 1.5L starter at 1.040. Then on brew day I made a 500ml starter and pitched the entire starter into my 7.5 gallon batch of wort after about 12 hours on the stir plate. The OG from my refractometer was 1.054 and tonight after 6 days of fermenting I took a sample and it was at my FG target of 1.009. The beer tastes good too, albeit flat.

In short, I can say that 7ml of Kolsch yeast frozen for 15 months in a regular consumer fridge with 23% glycerol solution was successfully used to brew a 7.5 gallon batch of beer. Tonight I'm taking a vial of Denny's Favorite 50 (Wyeast 1450), that was frozen in 4/2012, and will attempt to bring it back to life too. I'll post my results with the 1450 when my next batch of beer has fermented out.

Thanks again FlyGuy!

Only problem with this is you spend more on starter ingredients than you would on a fresh pack of yeast.

 

[Brewzologist]

Only problem with this is you spend more on starter ingredients than you would on a fresh pack of yeast.

As for the initial cost of the hardware to make the frozen yeast bank, on that you've got me!

But for making a batch of beer it's not cheaper to buy yeast in my case. I don't live within reasonable driving distance of a LHBS, so I end up paying to have my yeast shipped FedEx in a cold container. (That or they don't have the strains I want..) Also, I buy bulk DME so stepping up small starters is a negligible cost, and I'd be making a starter or two anyway even with a fresh pack of yeast.

P.S. FYI; The Dennys Fav 50 is currently growing on a stir plate from a 15 mos. old frozen vial for my next batch of beer.

 

[mredge73]

Only problem with this is you spend more on starter ingredients than you would on a fresh pack of yeast.

Yea; but that isn't the point though.
This thread expands on the hobby by encouraging you to dabble in a bit of microbiology for the greater good. This is a hobby and a hobby is a money/time sink.

 

[mredge73]

I froze some yeast a few months ago with about 20% glycerin per vial but I now notice that ice crystals have formed in some of the vials. Should I still try to use these or toss them?

I do 20-25% and they freeze solid.
I have been able to restart 18 month old yeast after a few days of incremental starters. No need to toss them.

 

[guldalian]

Yea; but that isn't the point though.
This thread expands on the hobby by encouraging you to dabble in a bit of microbiology for the greater good. This is a hobby and a hobby is a money/time sink.

This is true. Not saying you shouldn't do it. I have yeast in my fridge/freezer. Just saying maybe try to start out with larger volumes and cut down on starter steps. For me the more $ I save in any area of brewing is the more I can brew.

 

[suprchunk]

In short, I can say that 7ml of Kolsch yeast frozen for 15 months in a regular consumer fridge with 23% glycerol solution was successfully used to brew a 7.5 gallon batch of beer.

Glad to hear that.

But, I've also had success with rinsed yeast straight from the fridge far older than that.