I've heard the same about maple syrup. Probably has to do with it being mostly sugar. How much and what grade syrup did you use for what batch size?
I probably should have also mentioned this is for a 5gal batch if that isn't assumed by the quantities.
I normally just use whatever WalMart has to offer. The important thing, to me, is that it's genuine maple syrup.
As for the amount, I generally use about 2 tablespoons for my 1-gallon batches (for BOTTLING), but I do NOT know how this would translate to a 5-gallon batch - My sources say 1 cup for a 5-gallon batch, but I have found that, in general, their recommendation results in slightly-over-carbonated beer, so my suggestion (and that's all that it is) would be to use about 2/3 of a cup. Do your research, and I am sure that there is a good, reliable calculator out there somewhere - or, I am 100% confident that someone on the forum with more experience can assist with this, if you're interested.
As for the amount in the recipe itself, I am afraid I have no clue.
On that same note: Listen to Yooper! She knows her stuff, and is an invaluable source of knowledge and - more importantly - wisdom! If she's giving advice, it is for a good reason, and you can rest assured that you will have good results if you follow it.
Good luck, and let us know how it goes ~
