Freezing Yeast

[imark]

Just wondering if anybody has any experience with freezing yeast? I thought this was a non-runner but came across this link and it got me thinking it would be a good way to maintain a yeast bank.

[johnrm]

Good find Mark, an interesting read.

[Will_D]

yes, thats the basic procedure a glycerine dehydration to protect the cell wall from rupturing.

Always freeze as quickly as possible as this reduces ice crytal size.

However ( there has to be one ), this technique was developed for preserving yeast at -70C ( an available lab cryofreezer can do this - costs abot €7000 ) or better in liquid N2 - cheap if you can get the LN2.

A domestic freezer is good to about -25C and you should keep the vials in an insulated polystyrene container. Yes they will reach -25C BUT if the freezer runs a defrost cycle you yeastys will be protected from the elevated temps

[RichC]

I did this over a year ago but couldn't bring myself to risk a batch on the frozen samples. I now slant.
The correct procedure for this involves using a centrifuge to isolate a yeast 'pellet'. It's part of what put me off freezing