Keeping harvested yeast in a vacuum sealed bag

[MikefromMichigan]

I know harvested yeast deteriorates quickly after approximately 2 weeks or so if not used or just kept in the fridge.

Does anyone know how long harvested yeast will keep in a vacuum sealed bag? My thoughts are to harvest the yeast, and then immediately seal it using a foodsaver vacuum sealer for future use.

Thanks

 

[hendenburg2]

putting them under vaccuum won't help. the problem is most likely lack of food. yeast cells divide faster than once per 24 hours, which means that after two weeks, you've had more than 14 generations. this is, of course, at room temp. you might want to look into chemical means. also keep in mind that re-using yeast is not a good idea if you aim for consistency. yeast can drastically change flavor profiles after a couple of batches of beer

 

[rhamilton]

When I harvest yeast, I just pour the trub back into a sanitized White Labs vial (no washing, no glycol), reseal with the original cap, and store in the fridge I just did three starters last week using those vials which were sealed between 9/2011 - 12/2011 and every single starter took off like normal.

I haven't had a dead vial yet so I'd guess it would be good for at least a year. Just remember to make starter with it and know that as time passes, your viability will decrease so it will die eventually.

As for yeast quality, I'll see when those batches are done but they all smell normal.