noun_ a viscous amalgamation of old beer, sweaty feet and skin dust on the floor of a pub or club bar. Barmite has the exact smell and texture of Marmite, but should definately not be spread on toast.
Barmite is a clear sign that the landlord/manager is a lazy shitbag.
"went to work at this gopping bar the other night, i bet the landlady has barmite in her knickers"
Barmite (tm) The gunk that collects underneath a bar due to not cleaning all surfaces regularly.
Look under a pub bar under the places where beer is served from (beer taps) and glass shelves. See the build up of sticky mess known in the pub trade as Barmite (tm)
Beers drips that turn sticky and brown and look pretty much like Marmite. And the fact it is beer, it probably tastes like a sweeter version of Marmite.
Even better with added beer fly larve.