Add water, yeast, sugar, wheat gluten, salt, dry milk, oil, vinegar, potato flakes, and 4 cups of flour to the bowl of a stand mixer with a dough hook attachment.

Mix on low for 10-12 minutes (this is machine kneading).

After the mixing time, add additional flour, 1 tablespoon at a time. The dough is ready when it isn’t too sticky and can be handled. Give the dough time to work the flour in before adding more.

If it is gooey, add flour and mix after each addition, until the dough can be worked with your hands without sticking to them. I generally add 5 cups total flour for this recipe. It will depend some on your kitchen conditions and flour (it'll depend a lot on how your flour is milled, whole wheat flours vary more than other kinds in my experience). 

Form the dough into a smooth bowl and add it back to your mixing bowl. Cover tightly with plastic wrap.

Let dough rise for 1 hour or until about doubled in size.

Remove it from the bowl.

Divide the dough into two even pieces and form each piece into a loaf.

Place the dough in 2 greased loaf pan and let rise in a warm place for 1 hour or until the dough is about 1 inch above the rim of the bread pan.

Bake at 375℉ for 25-30 minutes until golden brown and sounds hollow when lightly tapped.

Remove from the oven and grease the tops of the loaf with a little bit of butter. 

Remove the bread from the pans and allow to cool on a wire rack before slicing (you can slice warm but the texture is best once it has cooled and the bread has set). 

Once the bread has completely cooled, store leftovers in an air-tight container at room temperature for up to 3 days, in the fridge for up to 5 days, and in the freezer for up to 3 months.