>>12213117depends on the organisms, there's some chad yeast that can grow up to like 25% abv and some other bacteria that can go pretty high too
if you're just trying to prevent any growth within the liquid anything over 40% is probably fine, but there may be spores or other inactivated stuff that will start growing again once it's in a more friendly environment
70% is ideal if you want to kill things quickly, but again there are certain things that can survive that
