I had some issues with the last lager I made, in that the crush was very floury and I had to mix the grain a lot to get it to drain properly then manually vorlouf to get the the pre boil gravity I was anticipating. By doing this I think I've extracted a lot of tannins as the finished beer is a bit astringent. I've been reading about how to fix this, and PVPP caught my eye as it seems to extract some off flavours. The trouble is, I have no way of filtering this out. Can I add PVPP to the keg, let it do its thing, then add biofine, let it do its thing, then run off a pint of sludge to get rid of the finings (and hopefully the puckering tannic mouthfeel)?