I've got a decent amount of leftover wine (ginger) after racking from my primary to a couple of demijohns. I want to use this for the topping up when I eventually rerack in a few months' time but I'm not sure how to store it. It's currently in a normal wine bottle (using about 650 of its 750ml) but I don't have an air lock that fits it though I've heard you can get away with just putting some muslin wrap over the opening.
My question ultimately is can I leave this leftover in the bottle with some muslin wrapped over it and then use it top up my demijohns when I'm reracking? Or should I just drink it right now as it tastes delicious (probably due to the unfermented sugar that remains... SG of 1046) and top up as normal with water/syrup when necessary?