What's the big deal with freezing yeast?

[Yob]

Not directly aimed at anyone but..

Seems to me that experimentation is to be encouraged, 'we' the freezers out there, are willing to put out Beer on the line.. And be consistent and accountable with our results... And not give up on it with procedural based failure.. And if you are unwilling to experiment yourself.. Sit back and wait.. ReResults are always pending.

My oldest stock is +12 months so side x sides are pending

 

[Camo6]

I'm just getting into this yeast freezing caper both for the fun of it and to have a reliable source of yeast close at hand.

I used to farm yeast in test tubes with sterile water and found some were quite usable up to a year and a half in the fridge. This was pushing the limits though and didn't always lead to a successful ferment. I found some samples started to develop a rubbery vegemite smell (from autolysis I expect) after about a year or so and this made me look into better practices. Keen to see the results from freezing.

Speaking of which, pushed the BB to it's limits last week with an ESB using a 1.5l starter of 6 month old Wy1469. Was busier than a stomal therapist, refreshing the blow off bottle repeatedly but now have a healthy sample of top cropped West Yorkshire for freezing and repitching. What a yeast!

20150115_184709 (720x1280) (2).jpg

20150116_122742 (1280x720).jpg

20150116_211440 (1280x720).jpg

A bit OT, just thought I'd share the pics from the brewbucket after transferring to keg. The bucket did pretty well to handle the krausen. A couple of times the blow off stuck and yeast got past the seal but once relieved it was airtight again.

 

[indica86]

In comparison, there is evidence that yeast stored under water is good for ~ 18 months,

What about yeast stored under beer - having a pH that is where you want it + ethanol to aid the preservation of the yeast?

 

[Yob]

Remember that alcohol is toxic to yeast.

 

[indica86]

Yes but is yeast not more tolerant to ethanol than other nasties?

 

[Yob]

Than water? No.

 

[stux]

After having my yeast library wiped out by a baby induced 18month brewing hiatus I willibg to give freezing a try

(Basically most of my wyeast splits are now 24-36 months old, and mostly look like peanut butter with oily/yellow liquid on top. Not comfortable bothering with)

 

[barneey]

So all of this really leaves me still sitting on the fence as to which is a better approach. Given both fridge and freezer space are ample, next time I am storing yeast I will freeze a couple of tubes and refrigerate a couple and will do a comparative test of viability after say 2 years and 5 years in storage. Stay tuned for an update in 2017.

Yeasty Balls (I'll let others explain) have (been proven) survived for 4 years in the UK. I'm just about to carry out my first year test.

 

[TSMill]

I'm going to look through my storage tonight, I think I will have some 1056 or 3068 in the order of 3 years old that I will attempt to revive.

 

[DJ_L3ThAL]

I just revived some WLP300 thats 12 months old, harvested the slurry/trub, didnt even rinse or add water was under the beer etc which it settled below due to my own laziness.

Made an awful mess when it spilled out over side after 24 hrs from pitching!!! Photo was at 16 hrs from pitching.

 

[TSMill]

Not directly aimed at anyone but..

Seems to me that experimentation is to be encouraged, 'we' the freezers out there, are willing to put out Beer on the line.. And be consistent and accountable with our results... And not give up on it with procedural based failure.. And if you are unwilling to experiment yourself.. Sit back and wait.. ReResults are always pending.

My oldest stock is +12 months so side x sides are pending

Yep agree 100%, and the same applies to testing the limits of yeast under water. Just been through the archives in the bottom of the fridge and I've come up with the following guinea pigs, that I will start experimenting with once my stirplate becomes free again.

2.5 years old:
Harvested from La Sirene Saison

3 years:
1768-PC English Special Bitter
2782-PC Staroprague

4 years:
3068 Weihenstephan
1056 American Ale

4.5 years:
3522 Ardennes
2308 Munich Lager

If I had to guess from a visual, I'd say the staroprague is the least likely survivor, followed by the Ardennes.

I did a bit more reading on yeast mutation, and as per the linked PDF below, it seems to infer that the rate of mutation is a function of the number of times the yeast is recultured (it assumes this needs to occur once every 6 months). For example, 10% of brewing yeasts (300 strains tested) showed change in flocculation rate after 10 years storage (20 recultures).

Linky:

http://www.pivarstvo.info/forum/files/yeast_propagation_and_maintenance_607.pdf

 

[TSMill]

Reviving an old thread (and an old yeast)...

I finally got around to making a starter with my la sirene yeast vial, which is now 3.5 years old. Pitched 3 days ago into 200ml of wort and now stepped up to ~1 litre.


https://drive.google.com/open?id=0B1FswRQjGOu3RUYwR1BHeTh4M1U

 

[Yob]

Was that under glycerine?

 

[TSMill]

Nope, under water in the refrigerator.

 

[DJ_L3ThAL]

Reviving an old thread (and an old yeast)...

I finally got around to making a starter with my la sirene yeast vial, which is now 3.5 years old. Pitched 3 days ago into 200ml of wort and now stepped up to ~1 litre.


https://drive.google.com/open?id=0B1FswRQjGOu3RUYwR1BHeTh4M1U

Sweet, I've still got the one you gave me, it's colour is much lighter than others and the ratio of slurry to water is quite low (heaps more water) than other vials with more slurry, less water which have gone a darker colour. Some are 'younger' than this yeast.

Perhaps there is a correlation between the water/yeast ratio that offers a far better long term protection?

 

[Yob]

Nope, under water in the refrigerator.

the trouble (possibly) with under water (not distilled) is the ingress of oxygen and the potential for mutation, while it is still an effective short tern solution, freezing slows the metabolism to essentially stopped (at -20'c) so thereby keeping the original characteristics truer for longer (in theory)

All that said, we all know that in practice we all seem to get results that suit us with a great variation in practices and procedures, ultimately, if the system we adopt works for us, that's all that's important.

Good to see a healthy looking result, all you need now is a temperature controlled stirplate for them

 

[TSMill]

Yes, the proof in the pudding will definitely be in the drinking!

 

[klangers]

You guys should start selling your services to act as a yeast library!

 

[TSMill]

Perhaps there is a correlation between the water/yeast ratio that offers a far better long term protection?

I think the yeast book talks about storing a match head sized sample in a vial, I have always tended to go a high water to yeast ratio as I figure this dilutes the effect of dead/ruptured cells, and therefore reduces overall mortality.

That said, I think some yeasts also just store better than others.

 

[Weizguy]

Yes, the proof in the pudding will definitely be in the drinking!

You have my attention, with both pudding AND drinking.
Please continue...