For most of my life I thought the different colors were dependent on how long it was boiled. Oh DUH! I now know the color is...is..is what it is! You boil it until it's the correct density & you get what you get. The time of year and the tree itself dictate the final product. The state sells little colored jars of liquid with grading labels. By eye you match your syrup to the color in a jar & that's it's grade. I've learned that I like dark amber or ex dark amber over the more clear stuff.
$55 a gallon? Wow! That's high! Last summer I paid $27 for a half gallon. Yaaaaa, that seems more reasonable!
Do you know real maple syrup can't go bad? If it get's mold on it, put it in a pan, bring it to a boil, skim the top and throw the skims away. You set to go once again!