Tex N Oz said:I've not read this whole thread but was wondering if anyone has mentioned that growing your cryo-culture in a very nutrient poor medium will greatly increase viability.
the cell walls of well fed yeast have a high tendency to rupture leaving only those colonies that are less than optimum because of pre-existing nutrient uptake issues.
Edit: I should elaborate considerably more. The yeast needs to be cultured @25°C for 72h in YM media.
Grown in 10ml vials.
The YM media recipe is such:
3g yeast extract
3g malt extract
5g peptone
10g glucose
deionised water to make to 1 litre
The cryoprotectant solution should be 10%v/v glycerol mixed equally with the innoculum
YM media is a product produced by Beckton Dickinson. It's like calling facial tissues a Kleenex of sorts.lael said:What is YM media?
Most of it's from papers I've collected over the years. I used to be hardcore into lyophilization.Mardoo said:And can you provide some links so we can learn more about this?
It's important to understand that raising yeast from a cryo or lypho state isn't as simple as pitching into some wort and off it goes. You must ALWAYS strike your sample first, then grown it on a petri dish and then start a 10ml starter then up from there. There's no easy way to start from a dehydrated sample. Even those samples that are frozen in a freezer are considered dehydrated.Yob said:so not really useful at all.. I keep mine at a pretty steady -20'c and am happy with the results thus far without it being overly complicated...
one of the things that got me into this side of the yeast ranching game over many other methods.
KISS
That's fair enough. How long are you able to keep viable samples?Yob said:Practical experience suggests different.
Results are speaking for themselves. Are there damaged colonies? Probably, does it make a noticeable difference? No.
DIGAF? No, the system I utilise works well enough and I'm happy with it and that's the important thing here.. It's a simple, effective, home brew solution to a yeast bank that works.
Perhaps you should start another thread on that method so as not to De rail this one.
Are you finding that it works better for some strains than others?Yob said:Well over 18 months currently... And counting
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