Phosphoric Acid source
Looking for a source for food grade phosphoric acid, 75% or so for adding to sparge water.
Try Surpass Chemical in Albany, NY http://www.surpasschemical.com/
You might be better off using H2SO4 (85%) instead as you would only need to use about 1/3 the amount to get the same effect. The PO4 acts as a buffer.....
Wherever / whoever you get it from, don't forget to ensure it is fodd grade, not just analytical grade. Sometimes analaytical grade chemicals contain too many contaminants such as arsenic to be safe to use in food products.
Have to say though, I'm not sure what the differnce between analytical and food grade H3PO4 is.
Your local 5star chem rep will sell you food grade Phos for cheap....for that matter any good chem supplier should be able to get it.