Bribie, thanks for the prompt to think about this stuff.
I usually get an absolute crapload of trub when I brew, standard BIAB. Dont think it affects the beers, and I dont worry too much about it, but its a bit annoying.
Did a brew today. Simple Pilsner/wheat grist.
Heated full vomume strike normally, mashed for 90 mins.
When heating to mashout, I usually lift the bag a little on a pulley to stop it getting burnt as I use a NASA and no false bottom etc.
I usually stir the shit out of it when its close to 78 deg, to equalize the temp. Whe I do this it will drop the overall temp by about 1.5 degrees or so.
There is usually a fair bit of visible (as it turns out) flour floating around.
Today, I stirred the grain once. Then, had the bright idea of jugging wort back through the bag.
I initially did it through the ball valve, but it was a but tedious.
I also considered that the flour would be riding the convection currents at the top of the wort, so I probably wasnt filtering it at all.
Started dipping the jug, and did this for 10 mins or so till it was at temp.
This stabilized the temp in the grain (still in the bag, and lifted about 20mm or so from the base of the pot) so I didnt get the drop and have to raise and heat again.
It also removed a large amount of the flour.
After whirlpool, I had stuff all crap left, just hops and protein.
I usually put the last bit of trub/wort etc into a 5L container, filter through voile, and dilute and use for starters. Instead of a heap of shit in this, just a little, filtered out, and much better overall retention.
So
Think I'll buy a pump. Heading towards a 3v, but really this is just a bastardization of a 1v, and it works so much better than straight BIAB.
Cheers