Re-using Yeast

[pfrichar]

I saved some of the trub from the bottom of a primary in which I used Safale 05 to ferment a 1.045 gravity ale. I packaged the slurry in two sanitized bottles, capped them and refrigerated them.

Will I be able to re-use this yeast and how?

How long will it keep?

[bobcat_brewer]

Assuming there were no flaws during fermentation (infection, stress, etc), you can use that yeast again. I don't wait any longer than 1 week before re-pitching.

[brewmeisterintng]

That is up for debate. I have quite a few different yeast sitting in the refrig. I always make a yeast starter before pitching to make sure they are still active. With that said... I have used yeast six months old that has been sitting in a Mason jar under a inch or two of beer without an issue. Keeping everything clean is real important.