I use plastic FVs, never noticed a plastic taste though. Are you cleaning with a chlorine based product, like VWP, by any chance?
Oh, and I used ALL of the steps discussed here, in a brew day yesterday, including skimming the hot break. I reckon photos say more than I can, but I will add that I hit my target OG of 1.070, but got 2 more litres into the FV, getting 16 rather than 14 litres.
So you know this isn't some odd super wide FV, spreading out the layer....
Nope, I didn't leave it all behind in the boiler either, it just never existed in the first place....
My system uses a recirculation pump though, so I did a thorough vorlauf, then did the whole draining the boiler thing etc, and didn't squeeze the heck out of the back, but rather tightened it from the top by twisting it.
Yes I used Protofloc, half of a tablet in fact. Yes I got a decentfoam up:-
But I skimmed it all off. So that layer is a tiny tiny bit of escaped flour, the rest is a minute quantity of hot break, and the rest is a bit of cold break that made the journey across.
So it's doable with BIAB, but not at all necessary, as it won't really impact flavour any. I just did it a) to see if I could, and b) because I knew I had to use an old FV with no transfer tap (keeping 1 of my 30 litre buckets free for bottling, the other has a porter in it, and my Spiedel has a golden ale in it), and I have a tremor that makes transfer using my auto-syphon a pain in the bottom...
The big thing here? 16 litres at target OG, rather than 14 litres! Less rubbish in the boiler meant I could transfer way more, tipping the boiler way more than I would normally.