As long as you are using genuine maple syrup (and not maple flavored Sugar syrup) you should be fine. I just bought grade B via Amazon.com -- because like you I could not easily find grade B in the shops.
Best of luck,
Melanie
Maple Syrup, Grade B, Org., 32 oz.
Price: $12.57
Availability: Usually ships in 1-2 business days from ShopNatural
Features:
32 oz.
Ingredients:
Certified organic maple syrup.