3-7 days, depending on how strong the culture is in the mix. I add mine to the starter I make the night before so its nice and strong.
As long as its kept cold and sealed it should be ok, best way to test it is use it, if it works then great no prob, if not, buy new
At the beginning u say its in the press and at the end u say its not being weighed down??. Proper stilton is not pressed its just granulated then fliped in a tall tube so its presses itself.
Going to check the one I made 8 months ago, the little one that was the leftover in foil is about gone, have used it in sandwiches, soups and popcorn Mmmmmmm, so il post a pic tomorrow on the barrel version, see if its dried out, cant believe time has flown so quickly