I just wanted to throw in my two cents about acids and browning. What Chau observed is correct, the introduction of acids into dough, or any other food product, does inhibit browning. While I don't want to get too biochemical, the lower the pH the more protonated amino acids become, slowing the rate of Maillard forming products. What this means for pizza or bread making is for a given tempuratue, acidic doughs will need to bake much longer in the oven to achieve the same brownness as less acidic doughs. However, one can try to compensate for the acidity by reducing the recipes hydration, upping the protien or sugar content in the dough, and increase the baking temperature.