I like it when potions have either fitting or ironic properties. Colour is usually something I'd imagine as fitting, while taste is more of a mixed thing. There are such a lot of things a potion can do, though, that you'll probably just need to take a dose, or read a label12 to know what's going on. Honestly, I definitely underdo the sensory stuff, there's so much potential with it.
With bottles, I would realistically use it to sort by function. One shape for transformatives, another for say healing potions, that kind of thing. I do like the idea of potions that can only be kept stable in strange bottle shapes, for some reason. It kind of ties in with this idea I have that alchemy involves a bunch of non-chemical aspects. Like maybe the sugar in this potion could be replaced with snow (the potion needs more white), or sand (needs more gritty), or artificial sweetener (needs more sweet). So a potion with a weird bottle might be incorporating the shape, or the way the potions flows into your mouth, as part of the potions. Kinda like how different drinks have different glasses, because the shape and flow affects the taste.
-
Or similarly blatant context clues like "The bottle is shaped like a [thing], to is [turns you into/gives you] a [thing]."
-
You could also just mislabel a potion. So I guess trying is the way to be sure. Maybe some kind of divination magic, actually?