yeast

[sims_l22]

Novice question how long can i store wyeast activator smack pack in the refridgerator. I have had one for about 4 months. Thanks

 

[Zen_Brew]

The further you get from the mfr date posted on the package, the less yeast that are going to have survived. At 4 months old the Mr Malty calculator viability section says you likely have less than 20% of the original yeast count still viable (12%). This means you need to substantially increase your starter size to get an acceptable pitch. It is generally not a good idea to use yeast that is much more than 2-3 months past it's date of mfr, and the starter size needed will start to increase dramatically. It's usually best to pick up a fresh pack of yeast inside 1 week before your brew date to ensure it is fresh, and give you time to make up a starter.

At purchase date + 4 months, the only way you will be able to use that yeast is to make a small starter of maybe a couple hundred milliliters to wake the yeast up that is left and get the colony size up some, and then step that starter up into a normal sized starter. I would not let the yeast go much longer, or I would buy a new pack.