Inconsistent grout color

[Markgreer]

I've grouted a Tropical Brown granite tile countertop with a Charcoal unsanded grout. As it dried much of it went to a dull charcoal color as planned. However, there are several darker and glossier areas. I used a power mixer and let the grout sit for 10 minutes as the bag suggests. Any idea why the discoloration?

It doesn't look bad... just inconsistent. Any remedies?

[Bill Vincent]

A good grout colorant will solve that problem.