Quite Amazing -- Yeast.

[chiller]

We all struggle to build up a viable yeast station in our fridges and there are many very useful methods for maintaining said farm.

I decided on Wednesday to brew a Scottish this weekend [thanks Batz ]

Normally I have a reasonable number of yeast to call on and ready to enter into beer making at a moments notice, however I wanted a particular scottish strain and the only "copy" I had was one I plated on a slant 3 years ago.

I decided to see if I could revive the slant.
This is the method I used to revive the slant.
Fill the slant tube with about 10 ml of starter recap and shake very vigourously. Place the sealed vial in the bottom of the water bed [for constant temperature]. Or just keep it warm.

24 hours later carefully ease the cap. A most beautiful sound was heard. My 3 year old Scottish yeast had revived and was now ready to step up.

The starter is at the 1.2 litre stage now and I will brew this afternoon.

For me this has proven that with ales at least long term slant storage in a fridge offers a viable means of maintaining a favourite yeast over a very long period of time.

I previously had read that slant storage offered around 6 months max whereas petri dish and agar was even less. My own eperience has allowed me the additional choice of small space storage as well as my normal sterile water storage.

Pint of Lager is a very accomplished yeast farmer and has great knowledge as to slant production and the materials to use.

Slants require significant work and attention to detail but if you desire to take your bio lab to the next level then this may be a viable option long term for you.

Now I think I froze some yeast from a large brewery a couple of years back --- so much yeast -- so little time.


Steve

 

[tangent]

Wow
Where do you get slant tubes in ADL Chiller?
Chemsupply?

 

[Kai]

I have been starting to build up my yeast library in 200mL specimen jars under sterile water. 3 yeasts and 5 tubes so far, with another yeast requiring one more water change before going into more tubes.

I've yet to use any yet though, so the proof is not yet in the pudding. I think one shelf worth in the fridge will provide more than enough yeast to satisfy most of my brewing needs.

Those of you who use the sterile water method, how much yeast do you like to have in the container? Do you feel there's a maximum desirable level, or more is better?

 

[chiller]

I have been starting to build up my yeast library in 200mL specimen jars under sterile water. 3 yeasts and 5 tubes so far, with another yeast requiring one more water change before going into more tubes.

I've yet to use any yet though, so the proof is not yet in the pudding. I think one shelf worth in the fridge will provide more than enough yeast to satisfy most of my brewing needs.

Those of you who use the sterile water method, how much yeast do you like to have in the container? Do you feel there's a maximum desirable level, or more is better?

[post="84641"][/post]​

Hi Kai,

With yeast under sterile water for long term storage [up to 12 months] the smaller the amount of yeast the better. So small in fact that you only have a mist of yeast on the bottom of the vial and when shaken the water goes slightly milky.

In such small numbers the yeast are happy to hibernate so to speak and not start feeding on themselves.

Amazingly the milky liquid from such a small apparent number of yeast is very viable. Take one ml and add to 10 ml of starter and 24 hours later step up to 100ml then the following day you can step up to a litre.

For short term storage up to about a month I've kept a large [cup] of cleaned slurry and activated it with a litre starter within a couple of hours.

Steve

 

[chiller]

Wow
Where do you get slant tubes in ADL Chiller?
Chemsupply?

[post="84633"][/post]​

Hi Tangent,

The place is Southern Cross Scientific.

Steve

 

[sosman]

Slants require significant work and attention to detail but if you desire to take your bio lab to the next level then this may be a viable option long term for you.

[post="84622"][/post]​

A few people have commented on this. I don't find slants much of a hassle at all, certainly not compared with trying to maintain slurries in bottles for any length of time.

As for the time they last, Brewsters yeast recommends re-slanting them every 6 months but a vendor is going to take the conservative route.

 

[Kai]

Hi Kai,

With yeast under sterile water for long term storage [up to 12 months] the smaller the amount of yeast the better. So small in fact that you only have a mist of yeast on the bottom of the vial and when shaken the water goes slightly milky.

In such small numbers the yeast are happy to hibernate so to speak and not start feeding on themselves.

Amazingly the milky liquid from such a small apparent number of yeast is very viable. Take one ml and add to 10 ml of starter and 24 hours later step up to 100ml then the following day you can step up to a litre.

For short term storage up to about a month I've kept a large [cup] of cleaned slurry and activated it with a litre starter within a couple of hours.

Steve

[post="84659"][/post]​

Thanks chiller. I was debating between needing a lot of yeast to ensure enough survive extended storage and minimal yeast to stop them chowing down on each other. It's good to hear your opinion on the matter.

 

[pint of lager]

For sterile water storage, I follow Graham Sander's notes on Ozcraftbrewer website. This means prior to storing under sterile water, the yeast is streaked onto petri dishes and that six-eight uniformly shaped and coloured colonies are selected and stored in the test tube. So there is only roughly the equivalent of a small match head of yeast in storage.

Short term, say three months, I use petri dishes as a source for starters. Yeast from a fresh plate takes only a day or two to get a 50 ml starter going, whereas yeast from a three month old plate takes an extra day or so to fire 50ml up.

Usually my strategy is to brew lagers in winter, ales in spring and austumn. So coming into lager season, I streak up fresh plates of all the lager yeasts in the bank. The best looking colonies from a plate go into storage again. Some plates may be restreaked so I have plenty of good looking colonies to make starters with. This means having plenty of prepared plates on hand, ready to restreak.

Medium term, slants are easier to deal with as I find they are less easily infected during transfers. But of course, these are almost impossible to do individual colony selection which is necessary for long term yeast wrangling.

For long term storage, I do wonder, are we getting a good representation of the yeast selected, or are we only selecting yeast that can survive the longest. I suspect a bit of both.

Some thoughts I have had but never researched, is to put some antibiotic tablet in the sterile water, this should in theory shut down any bacteria in the water, but long term (or in the pressure cooker,) it may actually break down into components that actually feed bacteria.

If there are any bakers out there, I am after some sodium proprionate or calcium proprionate. This is a preservative used in baking.

Anybody contemplating yeast farming, pop across to Ozcraftbrewing and read GLS's article, have a read of Sosman's brewiki site, he has posted some excellent info there as well as some very good links. There is also a very good yeast thread on AHB to read through.

Good to read that your slant fired up so easily Chiller. Those yeasties are marvelous beasties.