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.
Bro 2: No bra, The last 10% is 90% backwash anyway. There's basically no beer in there.