It's supposed to give you an option to ask for it when you ask for a drink from the bartender but for some reason it's not working but according to the patreon changes its supposed to be fixed later
I have found if you go to the right and down after entering the lower ark thing, ther will be a bunch of homeless people(sad but atmospheric, sorry I can't spell well I hope I spelled it right) if you go the the left person at the table near the top and gibe him a big fish he might give you a prompt or he might give you nonsense like saying there is an egg shaped shower in the PVP area of the bathhouse(you probably already knew that like I did XD) so just sleep then give him another fish the next day, and he might give you the right prompt then you can choose the house brew option. Sorry if you already knew that but I hope this helped someone.