The last 10% is 90% backwash

A phrase conveying the idea that the last 10% of a drink is comprised of 90% backwash.

Bro 1: Dude, you can't leave a wounded soldier on the table.
Bro 2: No bra, The last 10% is 90% backwash anyway. There's basically no beer in there.

by Nrbelex September 27, 2010