Beer was just a lame guess. I thought the same thing right after typing. I don't like beer. I'm not 21. Not familiar with prices. But I figured it was more than 50 cents a gallon. :P
He said water was close. Piss? Piss=water and it has wastes in it. Could be shit, since shit hits water, but lets not get into any unnecessary details with that. Shit has octane I think. LOL. Cow shit has methane content.