Let's Freeze Some Yeast

[Wolfy]

It is with deepest sorrow that I report that the brave and patriotic yeasties did not make it through Cryo.

I suspect my freezer just wasn't cold enough, well onto some slanting now and see if that works better - have the agar.

I'm very surprised that no yeast remained viable while it was frozen.
Rather than not being cold enough, my guess is the problem was with freeze-thaw cycles or something else.

I've been freezing yeast since last year - in small cultures, about 30% glycerin, and a method closer to what is outlined in the 'Yeast' book - while some (might even be strain-dependent) has suffered obvious losses, each of the dozen frozen samples still has some viable yeast.

Slanting yeast is easy, but it does get to be a-lot of time work and effort, so after reading the book, washing yeast and storing it under (distilled) water is what I'd like to try next for long term yeast storage.

 

[felten]

removed the superannuant liquid (beer)

the pensioner liquid? :lol:

 

[davo4772]

Sounds like better have too much glycerine than too little.

 

[Bribie G]

I must admit I was reluctant to put in too much glycerine as I thought it might taint the beer - OK I will definitely try it again and up the G content.
I have n packs of 1469 where n is a large number and I'll use one of these as an inoculator. I really want to get the method nailed because even though you can resurrect a smack pack after a few months, waiting 2 years for the next release is a bit of an ask. Plus I'd like to have stock to help out other brewers as they have helped me out (Bribie goes out to car to get violin)

Cheers guys, feel heaps better after your advice. :icon_cheers:

 

[MHB]

the pensioner liquid? :lol:

OK, ok - try Supernate God dam spell checker mutter mutter grumble

MHB

 

[Wolfy]

I must admit I was reluctant to put in too much glycerine as I thought it might taint the beer - OK I will definitely try it again and up the G content.
I have n packs of 1469 where n is a large number and I'll use one of these as an inoculator. I really want to get the method nailed because even though you can resurrect a smack pack after a few months, waiting 2 years for the next release is a bit of an ask. Plus I'd like to have stock to help out other brewers as they have helped me out (Bribie goes out to car to get violin)

By using smaller samples of yeast and being prepared to step-up a starter means you can use more glycerin without it being a problem in your beer. I've just finished testing the viability of my own yeast freezing experiments it's much more labor intensive and time consuming than your way, but by using small samples the viability is more easily. It just needs more work and then a starter to grow pitch-able quantities from the very small number of cells that are revived after being frozen.

I also think that yeast will 'keep' in their sterile packs much past the use-by date, but once again you may need to start with small starters or even streak the yeast out onto agar once very old packs are opened.

 

[davo4772]

Just froze 80mls of top cropped 1272 with 25mls of glycerine in a sterile 500ml glass bottle.

Not very scientific, about 30% glycerine. 25mls

Sitting in a small esky with another block of ice.

Has not frozen solid, still in liquid form.

Will leave it a month or two and see how it goes.

 

[argon]

Froze me some yeast last night :beerbang:

Tried it first with some good ol' US 05... i figure if things don't work out no loss. If it's all good i'll be freezing some precious 1469 i have in the fridge.

Couldn't have been easier... especially considering i used sample jars and syringes that are pre-sterilised in the packet.
Just made up my solution of Glycerin and pre-boiled water, brought it to boil again in microwave, added to sample jars, added appropriate amount (35ml in my case), then took some top cropped washed yeast and syringed 10ml each into 5 jars.

I now have 50ml of washed, frozen top crop US05 ready for starting up whenever i want. I can see this yeast harvesting and storage thing getting out of hand and filling up my freezer with sample jars of murky brown liquid. :blink:
:icon_cheers:

Success! :icon_cheers: Made a starter out of my frozen US05 yeast from April over the weekend.

Friday, took the frozen sample out of the fridge and let it defrost/come up to ambient over a few hours, then pitched to 200mL and stepped up after 24hrs into 2L. Yesterday evening had a nice thick creamy head on it... even when on the stir plate. Late last night decided to crash chill it after around 36hrs on the stir plate and this morning have a very nice 9-10mm layer of light yeast on the bottom of the 2L bottle. I'll be pitching tomorrow night into 40L of 1059 wort.

Got another 5 x US05s, 3 x 1469s and 3 x 3522s in the freezer. I'll certainly be doing this from now on when wanting decent yeast storage.

 

[Bribie G]

I'll have another go at ressurecting some of those tubes - I may have shocked the last lot by not thawing over 24 hours. Poor planning resulted in my rushing the yeast.

 

[davo4772]

I froze 30mls of rinsed ESB 1968 yeastcake with around 12 mls of glycerine (40%) Just under 2 weeks ago.

It remained in liquid form. Just pitched into an ESB after stepping up with 200ml, 1L, 1.5L. Starter fired up like any othe starter I have done.

Was only at minus temperatures for 2 weeks but the yeasties survived the freezing process no problem.

I also froze some 1272 with less glycerine, between 20 and 30%. Those samples have frozen solid so not sure how they wil go, no plans to make more APA's currently.

 

[stillscottish]

Just pitched a frozen 1007 into an Alt this morning.
Let it thaw in the fridge then brought up to room temp and made a starter. Took 1 1/2 days to come to life.

The first batch I froze failed. I suspect this was due to not enough yeast in the sample. I now let the yeast settle for a couple of days to make sure it's a good dense sample in the tube. 35 ml yeast topped up to 50 ml with glycerine.

Campbell

 

[Midnight Brew]

Bribie did you ever end up giving this another go?

Just gave this a crack with some Wy1318 London Ale III. My solution was a little less glycerin then whats recommended in this thread so hope all goes well. As it stands its frozen solid in my freezer. Have 3x vials with about 70billion cells in each.

I used this method: http://www.homebrewtalk.com/entries/freezing-yeast.html

 

[Yob]

he. he.. timely post.. doing this today myself



15% solution ready for the yeast :super:

 

[Bribie G]

Best of luck guys, I didn't replicate the experiment. I do a limited range of styles nowadays and find that three or four yeasts keep me truckin along and I keep them in PET bottles of slurry for repitching within a month or so. :beerbang:

 

[Midnight Brew]

Wicked tubes Yob! Plan to get some more 1318 into tubes tomorrow night then in a few weeks some 3068 when I ferment the other half of my weizen and then depending if she can be saved and cultured up, the mighty Greenbelt. Will keep some backups in the fridge just in case things go wrong. Collecting and freezing yeast could be very interesting.

 

[Yob]

Bribie, the starter I made was from a slurry of Greenbelt Ive had in the fridge since September 17, Ive run a starter and plan on getting 80ml of the yeast, 20ml into each tube to freeze. (the rest to pitch)

Its as much an experiment as it is wishing to save particular generations of the yeast., Say get 3 from successive uses and freeze. We all know yeast tend to hit a sweet spot with usage and I intend on finding out what it is for Greenbelt.

Id also like to build a comprehensive bank of the various yeast I use for APA, IPA, AIPA, etc.. Ive tried withslurry and it tends to get a bit long in the tooth and requires too much work to keep them all fresh.

I love these sorts of experiments anyway so win all round. Plus, it'd be good to have enough saved to be able to swap yeasts at Case swaps, a practice that seems to have died out in the last few years..

h34r:

 

[Grainer]

if you can freeze it quicker you will get better recovery as sending it to -20degC slowly causes shearing.. dry ice and ethanol/methanol is the way to go if you can get your hands on it.

 

[Bribie G]

My original experiment was in a fridge freezer, now I have a serious chest freezer I expect it would go better in that.

 

[Midnight Brew]

if you can freeze it quicker you will get better recovery as sending it to -20degC slowly causes shearing.. dry ice and ethanol/methanol is the way to go if you can get your hands on it.

Will give this a try today by just going straight into the freezer. With current samples I've whacked them in the fridge to cool down to 4c first. I thought it was best to cool to 4c first to build up some trehalose but then again that is a slightly different method where ascorbic acid is used with a 50/50 mix of glycerin/ypd medium. p199-200 Yeast book.

 

[MartinOC]

Wicked tubes Yob!

Timely!! I'm trying to organize a bulk-buy of these (& similar tubes) right now if you want to join the party:

http://aussiehomebrewer.com/topic/77474-melbourne-sterile-sample-tubes-yeast-storage/