Originally Posted by blacksailj
I was referring to adding the homemade chalk to mash as you would with store bought chalk to balance the pH. Would it be as efficient or effective?
That's actually what he was addressing. The stuff you buy at the store doesn't dissolve well at all either. It's the same stuff. Just because you get it at the store doesn't mean it will work as well as it could.
Just grabbed a few solubility products from Wikipedia. (under standard conditions but they act similar as far as brewing is concerned)
Calcium Hydroxide (Pickling lime): 4.68×10^−6
Calcium Carbonate (Chalk): 4.8×10^−9
Pickling lime is much... much... much more soluble than chalk. As in 1000x more.