Combine the water, milk, salt, pepper, and 1 tablespoon butter in a medium saucepan over medium heat. Bring to a boil. Slowly whisk in the grits and cook, stirring frequently so the grits don't stick to the bottom of the pan, for 1 1/4 hours to 1 1/2 hours. (We found that, depending on the size of the pan and the flame, the grits were sometimes creamy and done after 45 to 60 minutes. Still, the longer you cook them, arguably the creamier they become.) If the grits absorb all of the water and milk during this time, just add a little hot water as needed to thin out the grits until they reach the desired consistency.