Storing yeast under distilled water?

[Guido]

I seem to remember a Zymurgy article from a few years ago that told of different ways to store yeast for repitching. It recommended that yeast be stored for no more than two weeks under used wort. They also recommended storing yeast under distilled water and that it would be good for several weeks. Has anyone had any experience storing yeast slurries in the fridge under distilled water. It seems like a good idea since my White Labs yeast has hit $7.49 each.

[Bokonon]

In distilled water its supposed to be good for at least a year.

Here is one site that inspired me to start doing this:
http://www.mousetrap.net/mouse/brewing/dwyeast.html

I've got a bunch of cultures saved now and have only revived one of them for actual use but have grown 2-3 cultures just for testing to check viability.

Seems like a great method for long term storage that doesn't take up a lot of space.

If you want to save yeast for just a few weeks I would think under wort would be ok. I've made starters and wasn't able to brew for a few weeks and everything was fine. For longer term storage you could freeze the yeast using glycerin or save cultures on slants.

[boobookittyfuk]

i think that distilled water would not be that great for the yeast.

would seem that STERILE water would be better. If you can get glycerol....a 20% solution of glycerol in water would make a liquid that you could freeze the yeast. But you need a manual defrost freezer (frost free freezers are not as good for storing perisables). 20mL of glycerol plus 80mL water will give you 20%.


is $7 too much for another package of yeast?

[Guido]

i think that distilled water would not be that great for the yeast.

would seem that STERILE water would be better. If you can get glycerol....a 20% solution of glycerol in water would make a liquid that you could freeze the yeast. But you need a manual defrost freezer (frost free freezers are not as good for storing perisables). 20mL of glycerol plus 80mL water will give you 20%.


is $7 too much for another package of yeast?

I had planned on boiling the distilled water to make it sterile. Should have mentioned that. I know about freezing yeast, but I think that might be too much of a pain. I'm not really interested in banking the yeast longterm as I am in being able to extend it's life so I can get two or three brewing sessions out of it.

[Quin]

I think the issue with distilled water would that it would pull minerals/nutrients from the yeast because there wouldn't be any in distilled water.

[Guido]

I think the issue with distilled water would that it would pull minerals/nutrients from the yeast because there wouldn't be any in distilled water.

Actually, it work work the other way, the hypotonic distilled water entering the yeast to equalize the osmolarity. That's the same principal as when we use salt to dehydrate things. The water goes from the food in an attempt to equalize the salty environment. Anywho, this doesn't seem to be the case for yeast in distilled water. I'm more of a microbiologist, not a mycologist. Maybe someone can explain why.

[Quin]

I was speaking of the concentration gradient. Nothing in distilled water versus whatever is in the yeast.

[Guido]

Exactly, if anything were to happen, water would go from the lower concentration of particles environment in the distilled water to the higher concentration of particles environment in the yeast in an attempt to equalize the concentrations. This is what happens with red blood cells in distilled water. They swell and burst. That's why various medical testing uses 9% saline, which is isotonic--equal concentration. For some reason, this does not affect the yeast. Perhaps being a plant vs animal cell makes the difference, but I don't know why.