Let's Freeze Some Yeast

[kcurnow]

I did the same with some wort about a month ago, just to see how 'sterile' a tube could stay, the wort vial has been on the kitchen window sill ever since and no sign of contamination. I'm quite tempted to do as you have done mate and pre prep the vials so all I have to do is add the yeast.

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Hi Yob, yep in one of the other yeast books "first steps in yeast culture - rajotte" he gives steps for prepping sterile wort in jars and sterile slants in exactly the same way. Then they can be stored at room temp. Just need to leave the caps loose during the steaming and then tighten once out of the pressure cooker and still hot.

 

[Yob]

Nice one, exactly what I did, sort of just wanted to 'proof' that it was as good a practice as you can get at home, kind of has in my mind, if anything was going to go bad in that wort, would have by now, especially being in partial sun.

 

[kcurnow]

Nice one, exactly what I did, sort of just wanted to 'proof' that it was as good a practice as you can get at home, kind of has in my mind, if anything was going to go bad in that wort, would have by now, especially being in partial sun.

Yep and you need 15 minutes of wet sterilization under pressure. In the pressure cooker the steam should be at 121c at the highest pressure setting. It is the pressure bringing the temp up beyond the 100c boil mark that give the sterilization that boiling alone won't do.

 

[Camo6]

Hi Camo, I would suggest that the extra 5ml of glycerin will be the difference as in some of the earlier posts with higher %s of glycerin the mix wasn't freezing.

Cheers brewnut, I was hoping that was the problem.

I've got jars of sterile wort in passata jars that are six months old and kept at room temp. If those crummy jars can hold a seal I'll have no worries about my vials. My $50 Aldi pressure cooker is one of my most useful brew tools.

 

[MartinOC]

Hi Yob, yep in one of the other yeast books "first steps in yeast culture - rajotte" he gives steps for prepping sterile wort in jars and sterile slants in exactly the same way. Then they can be stored at room temp. Just need to leave the caps loose during the steaming and then tighten once out of the pressure cooker and still hot.

Ah, my first reading of yeast culturing techniques was Rajotte. Loaned the book to "someone" & never got it back :angry: .

I created agar "slants" in small McCartney bottles & pressure-cooked them, then screwed-down the caps once cooled.

For those concerned about potential long-term storage of wort after pressure-cooking, relax. Those McCartney bottles were kept out of the fridge (in a shopping bag, shoved in a box) in my shed for 10+(?) years & showed absolutely NO signs of contamination whatsoever. I chucked them out when I purged for the move to Kinglake.

 

[mofox1]

Quick question fellow freezers. Added another 5 vials to the chesty yesterday and noticed 1 vial from my first frozen batch, the one against the wall of the freezer, was not frozen. Figured the freezer, which is on the decking, had warmed so I turned it up and moved the vials to the bottom surrounded by frozen bottles of water. Today the vial was still not frozen but the others were. What's up with that? The vial may have gotten an extra 5ml of glycerine to the others. Could that have made the difference. Fwiw I'm going with Yob ratios as posted above. Will check when this weather cools down to see if it's still fluid.

Hey chief, I put mine in a small polystyrene box (from Coles, maybe 3 or 5 litres?) to maintain temps. Also an ice pack. I probably use a touch more glc as mine are mostly all liquid.... still yet to actually warm one up and revive.

 

[Yob]

Cam, a few% can make all the difference, %25 freezes, %30 does not as I recall (having played with mixture a bit) I wouldn't stress, at over %15 you're good to go.. I have one vial of 002 thatfroze among its compatriots that did not.. That worries me..

 

[Camo6]

Good news everyone! Just what I wanted to hear.

I've slowly filled the bottom of the chesty with frozen bottles of water as it's 3/4's empty most of the time, so this makes for a good nest for my vials. I'll look into making a decent storage container when I've done a few more packs. Cheers

 

[Yob]

Made a 3lt starter from my new greenbelt import, crashed it, made 3 vials and poured the rest back into a 2lt starter

2 hours later

 

[mofox1]

Damn. I just turfed 5 vials from a washed us05 due to a suspected infection from the parent batch... So far I'm down five with none to show for it.

Serves me right for trying to save dosh on packet yeast.

 

[Yob]

You didn't turf the vials though right?

 

[mofox1]

You didn't turf the vials though right?

At 15c ea, why not? h34r:


Nah, vials are safe and sound. Boiled the hell out of em too.

 

[mxd]

Hi Guys

I've read this thread (multiple times) and plan on doing my first attempt at freezing tonight.

I have 50 ml vials and plan on 25 ml yeast stuff from smack pack and 25 ml glycerin. (i've seen various combos in the thread this seems simple and easy for me.

Place it in the fridge for a day, then freeze AQAP (iced water etc.. then freezer with ice blocks around to help keep temp constant.

My Q's

I have seen it mentioned to boil the glycerin in the microwave, do you just put it in a cup and get it boiling, then let it cool and off you go.

1 of the packs I have I want for a brew I want to put down, so I thought I would freeze 4 vials then step up the 25 to 250 to 2000.

When I want to use a frozen I thought the 25 to 50 to 300 to 2000

When it's time to re-culture to restock do you use the slurry of a brew or do a 25 to 50 to 200 then to 6 or so vials ?


How does that sound ?

 

[Yob]

Hay matt, splitting from the pack, 25ml will yield about 5ml yeast solids in 5 vials, I step these up as follows,

100ml > 500ml > 2000ml

I can and do also freeze some off the slurry (rinsed of course) if the ferment was excellent so I'll end up with vials of different generations from original to about the third.

Ed: photo added



This is some 099 I took out of the freezer yesterday, 100ml overnight and into the 500ml this morning, seeing some action on it now, will go onto the 2000ml tmoz

 

[Yob]

Side note, I've reduced my glycerine to %25

12.5 ml glycerine
12.5 ml water

Autoclave

Add 25ml yeast from the pack.

 

[kcurnow]

Ok I have frozen my second batch of vials now. Included are OYL-500 Saisonsteins Monster, 3655- Schelde and 1217 - west coast IPA. I'm looking forward to using the 1217 in the Christmas Case swap cube I have sitting in the brewery.

 

[Yob]

thinking of doing this



when pulling out the tub to retrieve a vial, I worry about the temp swings, I naturally do so as quick as possible but part of the issue is that the first 50 or 60 vials I froze are written on the side of the vial not the top so identifying the vial I want can take a little time.

I hope this, in part, is a solution to a few of the issues, I can open the tub and lift out a "shelf" of vials with little to no temp swing, if I do get a power out, it'll last for days (brand new freezer so not worried about it carking it)

I should be able to get 2 shelves in the tub which should hold about 80 vials each shelf.

should do me... :beerbang:

 

[Alex.Tas]

I should be able to get 2 shelves in the tub which should hold about 80 vials each shelf.

Dude, you have a problem.





And I think it is contagious.

 

[Yob]

sooo, I went to do the 'ice shelf' thing the other day, got about half way the first time, knocked one over and the lot went down like domino's.. curses..

did it again, got all the way to the very last one and effing did it again... curses the greater.. turns out each layer will hold about 95 vials if I can ever get them in without knocking them all over..

anyway, I wanted to do an inventory of what Ive got frozen off already and get it on a spreadsheet so I can maintain it, though I'd show how easy it is to amass a decent library.

WY1056 3
GreenBelt (New) 7
Greenbelt (Old) 2
Greenbelt (3rd Gen) 4
WLP830 4 Wy1318 4
WY1318 8
WLP Burton 4
WY1217 8
WLP002 4
WLP041 1
WY1275 5
WLP013 1
WLP028 4
WLP545 4
WLP575 4
WY1272 3
WLP CRY HAVOC 6
WY1450 5
WLP001 3
WLP099 3
WLP SDSY 4
WY1728 4
WY1203 5
WY4766 5

total vials 98

*edited to add 1203 and 4766

 

[mofox1]

Nice stash! I'm probably sitting on around 30 or so, in about 10 different strains.

An spreadsheet inventory is a good idea - my 'gut feel' for how much/what type grain/hops/yeast I have around has not always proved effective come brew day. :lol: