I have some maple syrup that I bought maybe 9 months ago from a bulk foods dispenser, so I don't have any information about it, but it seems to have developed a slight carbonation. It tastes normal, and there's no mold, but there's a hint of alcohol in the aroma, and a bit of that carbonated sizzle on the tongue. It would appear that it's starting to ferment, but I've never heard of this happening to maple syrup. Is this normal? Should I be concerned about eating it?