talking to a Homebrew friend who says he buys 1 lb. of safale-04 and uses it throughout the year or two. I have many questions about this. I guess it lasts 36 months BUT: 1) how do you keep it? I understand you keep it in the fridge in an airtight package, but I understand that fermentis says when you open it, it should be used in 7 days. So how can you open it and still have it good for 36 months? 2) if it lasts 36 months doesn't the cell count go down? is it because it is a dry yeast and the yeast haven't been activated and the cell count would be like it is new? enlighten me please.