I have a slam back yeast dated aud 16, 05 is it still good and how long should I let it sit before using?? Thanks for your help. The date has MFG before it
MFG = ManuFacturinG date
It's probably not good to use as a "pitchable" smack pack, but there's a chance that there are viable yeast in it. Make a yeast starter with the contents to make sure it's good before you pitch.