Adding baking soda or baking powder to a bread recipe will make the finished product denser:

ENGLISH MUFFIN BREAD

2 tsp active dry yeast
3 cups bread flour
3 Tbsp nonfat dry milk powder
1/4 tsp baking powder or baking soda
1 tsp salt
2 tsp sugar
1 1/4 cups warm water

Put all ingredients in machine in the order suggested by the machine's manufacturer and bake on the regular bread cycle. The bread will have a flat or slightly concave top and a denser texture. During the final rising, sprinkle a little yellow cornmeal on the top.