I have an entire shelf in my fridge dedicated to liquid yeast harvested from previous brews. Most of these are from last year through Feb of this year. All sealed in mason jars stored about 35-38 degrees. I did brew a batch this year where I used harvested 1056 that I made a vitality starter. It sat on the stir plate for 36 hours at which point it appeared ready. I added to my wort and it took three days to get any activity. I could not get the FG down below 1.020. I brew 3 gal batches and used a pint jar of harvested yeast that was half full of yeast and trub (no hop). In the past, when using harvested yeast, I normally see activity within 12 -24 hrs. So I'm thinking in this batch the yeast was probably a good 9-12 months from harvest date and not in optimal condition. In hind site, probably should have pitched more even though Mr Malty said I used the correct amount. With that said, would it be best to get rid of harvested yeast that's in excess of 12 months old? Or would it be best to just use two half full pint jars instead of one when making a starter/vitality starter? How would one know if harvested yeast is bad? Would there be a certain aroma or look? I haven't brewed since Feb due to having surgery but now I'm ready to start back up but find myself somewhat transitioning to using dry yeast due to ease of use.