What is the recommended quantity for whole wheat crackers?
There are not same standard recommended quantities. You just use a hit and trial method from 0.4 to 0.6% and see where ever ur product settle down. Try to settle at low doses of ammonium bicarbonate as high dose will impact the texture and result in blisters.
For whole wheat crackers (Graham Crackers) a dosage of 0,5% Ammonium Bicarbonate works fine.
Andreas is right, it should not exceed 0,6% in most cases. Using whole grain normally impacts gluten development and thus stack heigh, so it is very usual that the amount for these types of biscuits are slightly higher, to attend the desired stack height. Just be careful with the ammonia released at the oven, it can be irritating for the people inside the plant. Also, make sure that you are not mixing alkaline and acid leavenings in the same emulsion forming stage, and try not to mix hot water and Ammonium bicarbonate at same stage as well.