Source: Joy of Cooking

Preheat oven to 400F. Grease 8 1/2 X 4 1/2 - inch loaf pan.

Whisk together thoroughly in a large bowl:

• 1c whole wheat flour
• 1c all-purpose flour
• 1/2  c old fashioned rolled oats
• 2 Tbsp sugar
• 2 tsp baking powder
• 1/2 tsp baking soda
• 1/2 tsp salt

Add:
1 1/2 c light or dark beer (but not stout), cold or at room temperature but not flat.
Fold until the dry ingredients are moistened. Scrape the batter into the pan and spread evenly. Bake until a toothpick inserted in the center and all the way to the bottom of the pan comes out clean, 35-40 minutes. Let cool in the pan on a rack for 5 to 10 minutes before unmolding to cool completely on the rack.