Guide to Making a Frozen Yeast Bank

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Okay but what is actually not being sanitized, the yeast or the glycerol or both etc?

And are you implying that the Star-San and 1-step cleaners are never really sanitizing the brewing equipment?

There's a difference between sanitizing and sterilizing. In this situation you want sterilization.
 
Okay so then what about yeast washing?

If I am going to freeze washed yeast should I add the glycerin as I would for a yeast bank?

Another option I have been considering is washing yeast and then freezing it instead of refrigeration. I have read that refrigerated washed yeast will lose viability relatively quickly (if not used within a month or two). So ideally, I'd like to be able to wash, freeze, use when I get the chance to brew again etc. and not worry about the loss in viability.
 
Okay so then what about yeast washing?

If I am going to freeze washed yeast should I add the glycerin as I would for a yeast bank?

Another option I have been considering is washing yeast and then freezing it instead of refrigeration. I have read that refrigerated washed yeast will lose viability relatively quickly (if not used within a month or two). So ideally, I'd like to be able to wash, freeze, use when I get the chance to brew again etc. and not worry about the loss in viability.

I would never bother freezing washed yeast. I usually end up with so much of it that I throw most of it away.

And it'll last a lot longer than a month or two in the refrigerator.
 
Okay but what is actually not being sanitized, the yeast or the glycerol or both etc?

And are you implying that the Star-San and 1-step cleaners are never really sanitizing the brewing equipment?

Sorry about the confusion. The distinction is between Sanitizing and Sterilizing. Sanitizing merely lowers the count of living contaminants to a specified degree. Sterilizing lowers that level to zero living contaminants (including spores and such)

StarSan is definitely an effective sanitizer. When used according to the label, Starsan will effectively lower contamination levels to an acceptable, sanitary level. One-Step, last I looked, no longer carries the sanitizer label because in order to do so they need to be FDA registered as a sanitizer (read $$$ for testing the product's sanitizing ability). For this reason 1-step can only be considered a cleanser.

In the case of yeast banks of any kind, you NEED to have sterile conditions, and this requires autoclaving everything you use; vials, water, glycerin, utensils, etc.
 
So ideally, I'd like to be able to wash, freeze, use when I get the chance to brew again etc. and not worry about the loss in viability.

If that is what you are looking for, you need to stick to buying fresh yeast for every brew session. Or, at a minimum, plan brew days so that when one primary fermentation is needing to be transferred, you are brewing that day or the next and pitching washed yeast from that now-empty fermenter's yeast cake. :mug:

(this is how many breweries conduct things)
 
Ideally you want to be as sterile as possible, but you certainly don't need absolute sterility. Brewing beer and handling yeast is much more forgiving than many make it out to be.

If you are freezing yeast, no matter where it came from, you need a cryoprotectant such as glycerin to maintain viability. If you freeze a gallon of washed yeast straight out of the fermentor then you will just kill it.
 
Pardon me if this has been brought up before, but can this method be used for preserving Lactobacillus?

Edit: I probably should have googled this prior to asking here. A quick search shows yes, you can preserve bacteria in a 15% glycerin solution with viability up to a year.
 
What if any possibility is there to harvesting just about any microbrew yeast? Is it possible to get yeast out of a microbrew that does not have sediment and grow a viable starter out of it? Or am I just taking crazy pills?
 
You can technically culture yeast from any unpasteurized beer. Just easier to do if the beer has lots of yeast left in it. IE un-filtered, low flocculating.
 
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.
 
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.

:mug: 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).
 
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.
 
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 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.
 
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
 
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!
 
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?

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?
 
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.
 
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.
 
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....
 
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?
 
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 :mug:
 
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?
 
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 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.
 
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!:mug:
 
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.
 
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!
 
SteveCO2 said:
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.
 
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.
 
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.
 
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.
 
mredge73 said:
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.
 
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