Chitosan was my first thought when i was reading through this thread just now. Seen some promising trial data about using it to block ML, though I wonder about the long-term viability of using it without sterile filtering before bottling. I would be paranoid about it coming back, perhaps irrationally I don’t know.
I should have added that the cheapest source of chitosan that I’ve found is ATP – cheaper than Scott, Lallemand, Enartis anyway. Theirs is just the all-purpose variety, rather than something more specialized. I wanted to use it pretty liberally and prophylactically last year since there was some suggestion that it might provide additionally provide some defense against smoke taint. I can’t say that was entirely successful for me, so maybe it’s not the solution to every problem.
Beware of the ‘super product’ - especially when combining with other products/processes. There’s no certainty of a specific outcome . . .
I don’t block ml on our rosé wines because I don’t filter due to small lot size, but I have been repeatedly surprised to find out that a lot of them only finished ml about 2/3 of the way, and with a standard bottling at of 30ppm SO2 free at 3.3 - 3.4pH I haven’t ever seen a referment. Nutrients are probably a big variable here too, but friends are taking the chitosan route these days though, but holding in barrel raises the ml inoculum risk most likely.