Warm weather = Icewine re-fermentation
This warm weather we've been having has had an unfortunate side-effect on my Icewine -- they've all started fermenting again. I guess I really should have used Potassium Sorbate in order to prevent any remaining yeast from becoming active again, given they were only chilled-down for a couple weeks post-fermentation. Apparently that's just not enough to completely stun all the yeast into submission.
My new plan is to chill these down again and hit them with Potassium Sorbate then see what happens. First I'll cool them in the fridge for a few days, then add Potassium Sorbate, give it a week or so, fine with sparkaloid/bentonite, give it another few weeks to settle, and then I'll filter with #2 filter pads.
The only problem I foresee is not having enough top-up wine to ensure full carboys after filtration. So I've bought about 20 lbs of glass marbles -- which should be enough to top up each carboy.