How long could one survive with only water and beer and no food?

I wanna see the Martian envisioned where instead of sustaining on pieces of potato, he drinks beer.

I also want to see more pirate-themed rants, preferably drunk.

Agreed. It's been common throughout history for people to live on only beer and water for a few weeks at a time.

I imagine you could survive at least a few months on doppelbock if you were in good health beforehand.