Backwash in beer

How much backwash (saliva) is there in the last few swallows of beer (or anything else)? My guess is that there is very little.

You might be interested in this old thread about “why the last sip of beer tastes so nasty”.

I’ve heard that the last 10% of any drink is just backwash.

Yeah, that’s what I have HEARD but I don’t believe it.