Let's Freeze Some Yeast

[MartinOC]

I can feel a bulk-buy coming on...

I can feel a bulk-buy coming on...

Got the taste for it,

Just can't wait for it.......etc....

If you want to organise, I can collect, since this bloke is local to my folks' place (ex-local to me).

 

[Yob]

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

tubes.jpg

15% solution ready for the yeast :super:

Late last week I thought I might take out one of my oldest, a Greenbelt now approaching 12 months from the look of it.. it was a few years old even then ... anywhoo, it went into a 100ml flask for ~24 hours > 500ml > 36 hours and is now in a 2000ml flask, within hours of hitting the 2L flask it was showing foaming so overall quite pleased with the performance thus far. This is due to be pitched to a 1.060 IPA on the weekend,

Ive got the case swap dark ale just finishing off with 1272 and its performed admirably, though it had been frozen for significantly less time I saw little difference in the starter activity times which Im quite chuffed about in terms of long term viability.

... FYI they dont ship international so if you plan on getting some you will need to sort out an alternative method than directly through the store

 

[kcurnow]

I have a question for all the yeasty experts here. I have an old (sep 12) packet of 3864 Canadian Belgian yeast that I want to revive so I can freeze it for extended storage. I have estimated viability of between 1-5% so was thinking of putting it through a couple of starters to build up the healthy yeast again. The question I have is the size starter to start with. If I go by the yeast book I should be starting with a 15ml starter to keep the inoculation rate around 67 million per mil (based on 1% viability leaving 1 billion yeast cells in the pack). That seems pretty small considering the packet will have 125ml in it however I guess most of that will now be dead yeast cells water and nutrients and I will need to rinse off the dead yeast once I have run the yeast through a few starters. Thoughts or comments on this approach? And recommendations on starter size? Cheers Karl

 

[Yob]

Probably a good idea to rinse as you say, once you have your rinsed volume, you will have a better idea of the starter size, If you put your rinsed yeast into a 50ml tube you'll get the amount of yeast measured, I've sometimes run the first starter in the tube, 1020 wort for older yeast, then onto 500ml (1030) then 2lt (1040)

Are you going to smack the pack? You might get a good idea of viability from that and could maybe go into a 1lt starter and rinse from that?

 

[kcurnow]

Yep pack has been smacked, waiting to see what will happen now. I might just put it into a 100ml starter and then rinse the result of that then go from there.

 

[Midnight Brew]

Hey Karl,

It is one of those situations where you dont have anything to lose except a bit of malt extract so I would go for it if you have the time. I think your calculations seem right if there is anything left in that pack and it could work. So on a stir plate steps would be as follows:

15ml
50ml
250ml
1000ml by here you'll know if she is alive and if the calculators are correct you'll have close to 190b cells.

I dont think it would be worth the effort crashing and decanting each starter but then again you might have to depending on the size of flask and being there will be that initial dead yeast from the smack pack in there. It might be easier to have an initial flask and just keep feeding those increments to it every 24 hours.

 

[kcurnow]

What is the ratio of DME to water to give approx a 1020 wort as I normally make my starters around 1040 using the 100g/ litre ratio.

 

[Midnight Brew]

Half, 50g/litre is about 1020.

 

[danestead]

Just reviving some 1217 that I froze 2 months ago. Fingers crossed as this is the first one ive attempted to revive.

 

[kcurnow]

Well i have pitched it into a 15ml starter yesterday and will add another 50ml today.

 

[Midnight Brew]

I've got the Greenbelt up and going again courtesy of Yob's efforts getting some pure stock sent over from Texas. Pack is swelling and starter is ready and patiently waiting for a little more swelling. :icon_cheers:

 

[Yob]

I left mine overnight and pitched this morning onto 3lt starter, spinning happily away now, stoked to have pure samples again.

 

[danestead]

Just reviving some 1217 that I froze 2 months ago. Fingers crossed as this is the first one ive attempted to revive.

Into the fridge for 12hrs then into a 200mL 1.020 starter then 500mL 1.040 and finally 1.5L 1.040 and all is going well.

Mixture on this batch was 50% glygerine/50% water solution then added in equal portions to the yeast therefore the final solution was 25% glycerine/25% water/50% yeast.

 

[Yob]

This is the ratio I've settled on as well.

Freezing is cool

 

[Midnight Brew]

Freezing is cool

Woah! He said it! He said it!

 

[kcurnow]

Well my 3864 freeze attempt hasn't gone too well. I am up to the 500ml starter and there is still no sign of any action from the old yeast. I have stuck a plastic bag over the top of the flask to see if it will inflate at all and give a hint of any fermentation activity. If not I will vomit and see if I can find some 3864 that isn't as old.

 

[kcurnow]

I have prepped a few vials with 50/50 glycerin and water (to the 25ml mark, to give me a final ratio of 25% water, 25% glycerin and 50% yeast solution once the yeast is added) and then pressure cooked them for 15mins to sterilise them. It was easy and now just need to add yeast. I am using WLP500 Trappist ale in the case swap brew so will harvest and freeze this.

 

[Yob]

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.

 

[Camo6]

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.

 

[kcurnow]

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.

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.