Harvested yeast

[Moad]

Hey Yob, a little OT but I've been looking for a good way to freeze yeast. Is the best way just into tubes with 15% glycerin + some boiled and cooled water?

I've read all sorts of conflicting info and I'm just starting on culturing/starters etc I mainly use dry yeast but want to start using more liquid and starters

 

[Yob]

Im using %50 slurry and %50 Glycerine

I started with %15 but have moved up the scale

you want sterile water if you can, pressure cooker or water you have boiled over a couple of days (best practice but not essential in my experience)

 

[Grainer]

9-10 is best in my experience with the right setup..going over this kills the cells and the Glycerol is actually toxic to the cells.

Cheers

at least 11 years of Microbiology was good for something !!

 

[Yob]

as in 9-10% Grainer?

Have to say, at up to 15% the solution still freezes causing stress, the higher amount stops the freezing and the results Im getting are fantastic.

That said, my 15% frozen vials still fire

 

[Moad]

Thanks yob will give it a go

 

[Grainer]

yes 9-10% tried and proven in labs..mostly for bacterial cells I must admit tho...

 

[Grainer]

I have a shortage of vials of late tho..might have to pillage some uni laboratories

 

[dave81]

do you generally harvest yeast from the fermentor after fermenting or just make an extra large starter and save some from there?
also what amount of yeast do you save in your viles?

Cheers
Dave

 

[Yob]

both, Splitting from the fresh vial/pack is golden.. but.. often its a particular frement that you want to capture so depending, I'll also rise then freeze as well..

I aim for 25ml thick slurry ~10-15ml yeast (25ml total) and top up to 50ml with the glycerine, fridge for a day, freezer ~ 5 years

 

[dave81]

both, Splitting from the fresh vial/pack is golden.. but.. often its a particular frement that you want to capture so depending, I'll also rise then freeze as well..

I aim for 25ml thick slurry ~10-15ml yeast (25ml total) and top up to 50ml with the glycerine, fridge for a day, freezer ~ 5 years

When msking a starter from su ch a small amoubt of yeast do you do stepped starters or jist a big one for what you require?

 

[Grainer]

stepped from vials

 

[dave81]

One last question I promise . What size steps?

 

[Yob]

Generally, 500ml then a 2lt

 

[Jkpentreath]

Da da dun da, mr malty.com