So do humans make the provisional "alcohol" or do the ogres? Earlier they said humans make it and deliver it to the ogres but here they say the ogres themselves make it, so which is it?
/canon
the earlier chapter you mention (ch2), said ogred were "supplied with it", but never mentioned whether it was made by them or not. taking both together i suppose it means they make it themselves (as a collective), and that is supplied to (individual) members of their society
/fanon
if i had to guess why they are able to drink it, it's probably a loophole in the curse where they are cursed to being unable to drink ethanol (drinking alcohol), but not other alcohols like isopropanol (rubbing/cleaning/industrial alcohol) or methanol (fuel alcohol)