In the bowl of a standing electric mixer fitted with the dough hook, combine 1/4 cup of the coffee milk with the yeast and granulated sugar; let stand until foamy, 5 minutes. Add the remaining coffee milk, the 4 1/2 cups of bread flour and the butter and salt. Mix at low speed until the dough just comes together, 2 minutes. Increase the speed to medium and mix until the dough is smooth, 5 minutes. Transfer to a greased bowl, cover and let stand in a warm place until slightly risen, 2 hours. Divide the dough into 4 pieces.