Thanks a lot erikpete18 and jonmohno. Your both answers gave me good idea on where to direct my research. This belgian IPA partial mash will be my third brew. So, I am still learning.
So, thanks to jonmohno, I found out in some literature that we need to balance the fermentable. so the weight of candi sugar by percent solid by fermentability should be equal to weight of maple syrup by percent of solid of maple syrup and by its fermentability. Both have a fermentability of 100%. Rock candi sugar have a percentage of solid of 100% and the maple syrup is about 33% of water. So in that case I should substitute 2.2 lbs of maple syrup (1.5lbs / 0.67)
In the order hand if I use the yield in ppg of each sugar, I get more confuse. erikpete18 says the ppg contribution of 1 lbs of maple syrup is 30. Which seems to be right because after googleing, I found out the ppg of maple syrup to be 31. For candi sugar, it doesn't seem to have an agreement on the ppg. Some writer use a ppg of 46 and others 36. With a ppg of 36, ok we obtain 1.8 lbs. But for a ppg of 46, the maple syrup to susbstitute become 2.3 lbs, which is pretty much in line with the first method of calculation.
So, I guess that 2.2 lbs of maple syrup will be my target for this recipe. Let's see what happen.
