Proof yeast in warm water directly in the KitchenAid mixing bowl. If your kitchen is cool, rinse the bowl with warm water to warm it up first. Set aside for 5-10 minutes to allow the yeast to bloom.

Melt butter in a small saucepan. Stir in the buttermilk to bring it down to a temperature that is safe for yeast. Test it with a finger, it should just feel warm, if you use a thermometer, 110 degrees F. Add to the mixing bowl and then add the honey. 

With paddle attachment in place, turn the mixer on low speed, 1, and add whole wheat flour a cup at a time, then the baking soda and salt. Once it is nicely incorporated, add the white flour ½ cup at a time until you have a soft dough that pulls away from the sides of the bowl. Hold back some of the flour, you may not need it all!

Remove the beater and cover the bowl. Let rest for 5 – 10 minutes. This gives the bran in the whole wheat flour time to hydrate which softens the edges making the dough easy to handle.

Now add the dough hook, but before you start, take a moment to butter the hook and the collar all the way up and over the top. This will keep the dough from climbing up into the machine where it doesn’t belong.

Lock the head and set the machine on low speed again, 1. Let the mixer knead for 5 minutes. Now it’s time to get our hands in the bowl. The best way to know how the dough is developing it to touch it. It should feel smooth and resilient. Bread dough made with whole grain flour will retain a certain amount of stickiness, like the sticky side of a Post It note. This is okay and does not need to be eliminated. 

When you think you are done kneading, let the dough rest 5 minutes and then perform the windowpane test. Use clean scissors to cut off a walnut-size piece of dough. Slowly pull and stretch the dough to see if it will hold a thin membrane. Hold it up to a window; if you can see light through it, you are done kneading; if not, knead another minute or two, rest 5 minutes, and re-check.

Wash your mixing bowl, dry it, and grease it. Give the dough a few turns by hand on a lightly greased counter and shape it into a smooth ball. Place dough in the bowl, smooth side up. Cover with a bread cloth, cotton (not terry) dish towel, or a plate. Allow it to rise in a protected spot until almost doubled, 1 hour. 

To check if it’s done rising, do the poke test: take 2 fingers and gently press the dough. When you withdraw them the indentation should remain, but the dough should not “sigh” or deflate.

Meanwhile, grease your loaf pans.

Turn the dough onto the work surface and gently flatten it with your greased palms to remove air bubbles. Using a bench knife or a chef’s knife, divide dough in half. Press one half into an 8×12-inch rectangle. Fold in thirds like an envelope. Pinch bottom seam to seal. Place seam side down in prepared loaf pan. Repeat for second loaf.

Cover the pan and let rise until dough curves nicely over the top of the pan, about 35 minutes. Set the oven to 350°F (175°C) to preheat. The touch test will help you determine if your bread is ready to bake. Instead of poking your fingers into the dough, this time simply touch the dough. It should barely show your fingerprint. 

Bake 35-40 minutes, until the loaf is well-browned and done. To test for doneness, carefully tip the loaf out of the pan and inspect the bottom. The crust should be evenly browned and sound hollow when thumped with a finger. A food thermometer will read 195-200°F (90-93°C).

Cool baked loaf on a wire rack for a crisp crust or on a wooden breadboard for a softer crust. If desired, brush warm loaf with melted butter. Wait at least an hour before slicing to allow the crumb to set.