Shelf life of yeast.

[Sailor323]

People are often concerned about the viability of yest after the use by date. Of course, this depends on how the yeast has been stored. I recently started a batch of Gamay with RC212 that bore a use by date of 01/04 (20 years ago!) It had been stored in the freezer since 2001. I rehydrated with Go-Ferm, added sugar and it was off and running within minutes and the Gamay was fermenting within 12 hours. I've done the same thing with EC1118.

 

[wood1954]

That’s some tough yeast. I put some Renaissance yeast in the freezer and it died.

 

[winemaker81]

Vendors now say to refrigerate, not freeze. Years ago I was told to freeze that, and it often survived only a year. I have Avante that is 3 yo and going strong.

 

[Rice_Guy]

From a micro lab or frozen bread factory point of view, yeast is quite hardy for years. The problem that is likely to show up with freezing yeast is that they don’t like freezing and thawing over and over. The moisture stress ruptures cell walls.
Dry yeast should survive freezing since there is limited moisture to freeze. I have sealed packets of yeast in a refrigerator that are in the ten year range. I would trust the product.

 

[Raptor99]

The problem that is likely to show up with freezing yeast is that they don’t like freezing and thawing over and over.

I think that for long term storage of any food item, a chest freezer that is NOT frost free is better than an upright. The daily brief thaw cycle of frost free freezers and/or the temp change from opening the door of an upright freezer degrades the food (or yeast) over the long run. I have kept yeast in a chest freezer for several years without a problem.

I have sealed packets of yeast in a refrigerator that are in the ten year range. I would trust the product.

Glad to hear that. Currently I keep my yeast supply in the refrigerator rather than the freezer.