This is a review of an article from the German journal "Haushalt und Bildung" [Household and Education].
Homemade bread is tasty, but often fails to compare to a fresh loaf from the bakery, at least in shape, consistency, and general appearance. Research at the University of Hannover [Germany] has found that a small trick is sufficient to greatly enhance the quality of homemade bread.
Professional bakers use steam, actually water vapor, to assure proper rising of the bread, unfold its aroma, achieve a nice crumb, and get a lovely brown crust. Commercial bakers can simply program the oven for the desired amount of steam, something that could not be done in home ovens until recently. Experienced home bakers are familiar with the recommendation to place a cup of water in the oven while bread is being baked. In the German journal "Haushalt und Bildung" scientists describe the type of bread this technique is suited for.
In the experiments, white pan bread, whole wheat and white pan bread, and a yeasted braid were baked. The loaves, made from the same recipe, were baked with and without water, and with heat from a lower element, a top element, and a convection oven. The results were then judged for form, appearance, mounding of the loaves, tenderness, structure, aroma, and flavor.
They discovered that when a container of water was added to the oven while baking white or white/whole wheat bread the surface was evenly browned and glossy. In addition, when the white/whole wheat bread was baked with a scant 150 mL of water in the oven fewer cracks developed in the crust, and the typical "roasted" aroma was present.
The yeasted braid bread was a different story. It had been brushed with an egg wash [beaten egg and milk] prior to baking. When baked with upper and lower heat, the addition of a container of water in the oven was detrimental. The surface of the bread looked "washed out," had browned unevenly and developed blisters. When baked in a convection oven the braid did somewhat better with the addition of steam, but there was no noticeable difference in the browning.
All in all, adding a small cup of water in the oven is a useful technique that can bring home bakers some of the advantages of professional baking.