Guide to Making a Frozen Yeast Bank

[mountainman619]

I'm not using a sticky label at all. I created it in Word, printed them on regular paper, cut them out and then taped them on with scotch tape. Vials have to be super clean and even then it helps to wrap the tape around and back onto its self. Otherwise they just slide off.

 

[TomRep]

Good to know. thanks for the reply mountainman (and all of you, really).
tom

 

[Brewzologist]

I'm not using a sticky label at all. I created it in Word, printed them on regular paper, cut them out and then taped them on with scotch tape. Vials have to be super clean and even then it helps to wrap the tape around and back onto its self. Otherwise they just slide off.

Nice work on the labels... Any chance you'd be willing to post a copy of your Word doc?

Thanks;
Steve

 

[TomRep]

mountainman619- Another question. what is the "1002PT1SKYA1" on your label? I assume it's some kind of code for you or the production code on the yeast vial? Thanks!
tom

 

[Zamial]

I have regenerated a vial of Kolsh yeast that has been frozen for 6 months. It is aggressively chewing through an Oktoberfest and a Kolsh.

 

[uncleben113]

I really want to do this to save money but I'm driving myself crazy trying to find a good source of autoclavable vials.

What I've been doing up to this point is saving samples of each strain in small glass bottles. These bottles were bottles of tonic water that I salvaged from work. They cleaned up nicely and don't take up tons of space. Here's a shot:

I'm wondering if I can do the same thing but add glycerine and freeze them. Maybe I could have a small bottle full of yeast/glycerine mixture and just pour some out when I need to.

Thoughts?

 

[dragonbreath11]

Heads up for anyone looking for glycerin online.

http://www.mountainroseherbs.com/bulkmisc/bulkmisc.php#bu_gly



16oz for 8.75+ shipping. They also carry bitter orange peel, irish moss, and many other brewing spices and goodies mostly organic if anyone cares.

 

[mountainman619]

Nice work on the labels... Any chance you'd be willing to post a copy of your Word doc?

Thanks;
Steve

Steve - I am willing, but can't from this particular computer. However you can open a new blank document then create a table with 2 columns and 5 or more rows. That gave me 10 spaces to fill. I will try to remember to make one and post it tomorrow (Sunday).

mountainman619- Another question. what is the "1002PT1SKYA1" on your label? I assume it's some kind of code for you or the production code on the yeast vial? Thanks!
tom

Tom - It is a production code from the White Labs vial. It allows me to track strains that are the same but from different original sources. If I end up with a problem I can back track and know which vials could be suspect.

 

[dragonbreath11]

Yeast freezing is great. Has anyone here froze yeast with a full pitchable rate? Wouldn't it be a good idea to freeze the whole volume of yeast that you're going to pitch using the glycerin method? Then 24 hours before brewday you just take it out of the freezer, put it in the fridge, and pitch without a starter. Of course if you brew often then you'd probably run out of fridge space pretty fast.

 

[strumke]

Does this look like the right amount of yeast to have (16ml vials)? Too much liquid? I have had them in the fridge for 24 hrs, tomorrow they'll go into the freezer. Do I shake them up again before freezing?

 

[guldalian]

I'm sorry if these questions were already answered at some point, but I don't have time to read all 400000 posts. I am VERY interested in anything that can contribute to the lowering of brewing costs.

1. How long can the frozen yeast be kept?Indefinitely?

2. Wouldn't you only want to take yeast right out of the pack/vial instead of from the fermenter yeast cake? Seems to me there would be hop trub and other particulate in that stuff.

3. Can you do this with rehydrated dry yeast? I realize dry yeast can keep for much longer, and is already cheaper, but free is even better.

 

[Moose777]

Yes that's plenty of yeast. In fact that's a lot more than I've put in. Shake them before you freeze just to be sure the glycerin is well mixed in.

 

[SnowBird]

Thank you!

 

[SiriusStarr]

This thread seems as good of a place to get answers as any, so... I plan to start freezing yeast, primarily because of the limited availability of WY3864, which I'm getting my hands on while it's around right now. I do not have a pressure cooker, however.

I plan to use sterile 50 ml conicals, so sterilizing vials is not a concern. Thus, my only concern is sterilizing my glycerol stock solution (and any equipment that will touch the yeast). There is of course no household way of sterilizing other than a pressure cooker (the efficacy of bleach solutions on surfaces/equipment is debatable), but boiling will kill anything except endospores. Tyndallization is another possible option for solutions, but is also of inconsistent efficacy (as well as being a pain in the butt).

My question is this, though. Is complete sterilization (i.e. more than what can be achieved by boiling) actually necessary for freezing yeast, given that the source of the yeast itself isn't sterile. I haven't seen anyone recommend autoclaving/pressure cooking one's Erlenmeyer and starter wort, just boiling it, in which case the starter itself will never be truly sterile and will be a far greater source of potential contamination than the glycerol/equipment.

Anyways, thoughts? Am I fine just with boiling everything, or do I really need to purchase a pressure cooker? I don't plan to passage yeast more than maybe twice, so there won't be repeated expansion of contaminants.

Thanks!

 

[orangehero]

If you have good sanitary brewing technique you will be fine. You're right that you will be able to use it for fewer batches. The level of contamination isn't necessarily either or for ruining a beer...you may just see a gradual degradation in flavor quality and not something that is necessarily detectable until you've reused the yeast several times.

Best practice is of course to keep everything as sterile and sanitary as possible. I sterilize my starter vessel in the oven (I use 4L wine jugs and place them in the oven at 320F for 2 hours and let it cool slowly overnight) and use precanned sterile starter wort that I prepare in batches in my pressure cooker.

 

[SiriusStarr]

If you have good sanitary brewing technique you will be fine. You're right that you will be able to use it for fewer batches. The level of contamination isn't necessarily either or for ruining a beer...you may just see a gradual degradation in flavor quality and not something that is necessarily detectable until you've reused the yeast several times.

Best practice is of course to keep everything as sterile and sanitary as possible. I sterilize my starter vessel in the oven (I use 4L wine jugs and place them in the oven at 320F for 2 hours and let it cool slowly overnight) and use precanned sterile starter wort that I prepare in batches in my pressure cooker.

This is not what I need to be hearing. XD I'm a biologist by profession, so I'm already paranoid about sanitization/sterility. I guess buying a pressure cooker is unavoidable for me at this point...

 

[mrmysandwich]

Let me add a data point here. I had about 20 yeast lines stored in cryotubes in 15% (v/v) glycerol and sterile water (I just removed pure colonies from a plate and put them into the water/glycerol mix). I stored the tubes at -20C in a frost freezer, and after about 18 months of this I started to notice a dropoff in viability. I couldn't get them to grow when I streaked a little bit on a plate.

Now that I'm restarting my library, I'm planning on doing 40% glycerol, in an attempt to avoid freezing (15% froze at -20).

Furthermore I'd say that a pressure cooker is an absolute necessity - things need to be sterile if you're stepping up from a small amount of yeast, there is no room for error here.

 

[samandbekah]

FYI, you can buy glycerin locally. I don't bank anymore (not pure yeast, anyway) but I used to get glycerin at Walmart, in the pharma aisles. I probably posted this info about 100 pages back in this thread, but thought I'd throw it out there again.

So would something like this work ?? --> http://www.walmart.com/ip/Humco-Skin-Protectant-Glycerin-Usp-6-oz/10417582

Also - I have been reading up and down this post regarding the glycerin and pressure cooker...

I use star-san and LD Carlson 1-step sanitizer to sanitize EVERYTHING I use... If I boil small mason jars and then star-san them afterwards (in essence doubling the sterilization for insurance pts) will this suffice to add the glycerin and yeast slurry and then freeze?

Or is it that the glycerin itself is what needs to be sterlized, hence the pressure cooker?

 

[mthompson]

So would something like this work ?? --> http://www.walmart.com/ip/Humco-Skin-Protectant-Glycerin-Usp-6-oz/10417582

Yes, that glycerin will work. I use the Walgreen's variety. USP grade Glycerin is USP glycerin is USP glycerol...all the same (99.7%).

I use star-san and LD Carlson 1-step sanitizer to sanitize EVERYTHING I use... If I boil small mason jars and then star-san them afterwards (in essence doubling the sterilization for insurance pts) will this suffice to add the glycerin and yeast slurry and then freeze?

Or is it that the glycerin itself is what needs to be sterlized, hence the pressure cooker?

None of these actions will sterilize. This means that, compared to using a pressure canner as an autoclave to actually sterilize, you will have higher counts of all living contaminants. This higher count will multiply and amplify at each starter step, and your results could suffer negatively as a result of the contamination.

Ex: 4-step starter from frozen vials, with either 1 contaminant or 1000:

1→2→4→8→16
vs.
1000→2000→4000→8000→16000​

Pony up $100 for the presto 23qt. canner, make you yeast library properly, and then learn to make and can wort (at different ° plato) for making starters without any prep work. If you want to cook or can other things (veggies, meat, etc.) get a 3-piece regulator too.

 

[samandbekah]

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?

 

[bja]

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.

 

[samandbekah]

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.

 

[bja]

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.

 

[mthompson]

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.

 

[mthompson]

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.

(this is how many breweries conduct things)

 

[orangehero]

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.

 

[TastySalmon]

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.

 

[fc36]

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?

 

[guldalian]

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.

 

[guldalian]

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.