Yeast Banking

These little beasts do all the hard work. Share how to keep 'em happy and working hard.

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CopperFiend
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Yeast Banking

Post by CopperFiend »

Dear Yeast Officionados,

I am buying a very expensive yeast culture for a specific task. I am currently on with making and autoclaving some nutrient agar slants for propagating it when it arrives. I am then planning to refrigerate some of the propagated slants (said to last up to 6 months viability) for day to day use for starters and then storing some under sterile distilled water for longer periods (apparently up to 3 year viability).

My question to you helpful people is... are there any easy and safe (no liquid nitrogen please!) methods to do in a basic yeast lab (my kitchen) to make a viable yeast bank for long term storage to make new starters forever? Is there any better way I've missed?

Cheers!
Copper
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Expat
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Re: Yeast Banking

Post by Expat »

I would dry the yeast on a sheet of parchment paper, and then store it in an air tight container and freeze it. Dry storage is going to be a lot more stable than wet.
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howie
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Re: Yeast Banking

Post by howie »

it's all new to me, but i found a enlightening video on the subject......
CopperFiend
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Re: Yeast Banking

Post by CopperFiend »

howie wrote: Fri May 14, 2021 7:57 am it's all new to me, but i found a enlightening video on the subject......
Yes, that's making a starter which is most of the idea but it's the viable storage (so this very expensive yeast can be cultured at any time and used to make a starter) that I'm looking for any better ideas.

Ex-pat - drying could be an idea but then culturing new (unmutated pure) strain would be unlikely after a few generations of that?

Copper
amh71
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Re: Yeast Banking

Post by amh71 »

Have a read on some of the beer forums, there are a number of tutorials.

I've built up a little bank of different yeasts in the freezer. Start by making a starter and then cold crash it in the fridge for 24 hrs, I bought some 50ml glass jars with screw caps, put 10ml of glycerine in each, losely capped and then cooked for 30 minutes at 130C in a steam oven, a pressure cooker would do the same. Once cool pour off most of the liquid from the starter and filled each jar to about 40ml, close the caps and leave in the fridge for 48 hrs, then freeze.

Defrost a jar and make a starter as soon as its defrosted. When you get down to last few jars use one of them for a new batch, label well so you know how old, how many generations etc.

If you have a frost free freezer put the jars inside a small cool box or a box with ice packs to protect the yeast from the temp variations.

Been doing it for a few years and yet to have a failure, just make sure that everything that gets near the yeast goes in the pressure cooker to make sure its sterile.
CopperFiend
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Re: Yeast Banking

Post by CopperFiend »

Thanks Amh, just wondering when you say pour off most of the liquid and fill each starter to 40ml, what are you filling with? Distilled water?

Copper
amh71
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Re: Yeast Banking

Post by amh71 »

When you make your starter leave it to ferment out and then put in the fridge for 24hrs, the yeast will drop to the bottom leaving a, hopefully, thick sediment and clear beer on top, pour this beer away and then fill the jars with the sediment from the bottom, which is your yeast.

Sorry if not ciear, been sampling the wares..... spend some time on the beer forums, there are lots of threads on yeast and lots to learn about our tiny friends.
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Demy
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Re: Yeast Banking

Post by Demy »

I don't know if that's the answer you are looking for but you could divide your starter yeast into many small doses and make starters with them when needed.
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