One must be careful with steam if a brown crust is desired. Keeping
steam in the bake chamber too long will actually inhibit browning. The
ideal circumstance is to fill the chamber with lots of steam, ideally under
pressure, at the beginning of the bake. This steam should be allowed to
linger until the bread has expanded to its full volume. Beyond this point
the steam will inhibit browning.
My preferred method for steam generation is to place a HEAVY cast iron
vessel (large skillet or dutch oven) on the oven floor. Preheat it with the
oven. When you load your bread, throw a good sized handful of ice cubes
into the cast iron pan. This will provide a substantial amount of steam for
quite a while, and the extra thermal mass of the cast iron will help retain
heat in the oven while the door is open. Use a hot oven (425 to 450F).
Once the steam is on the crust of the bread it will gelatinize the
starch. As this gelatinized starch dries out it browns more easily than a
non-gelatinized starch (more free sugar available for Maillard reactions, or
something...) If it's not allowed to dry (i.e. too much steam) you will
get a pale crust.
If you want a crisper crust, watch the loaf closely. After it has
reached full volume and begins to brown, open the oven and evacuate the
moisture for thirty seconds or so. This is a good opportunity to CAREFULLY
turn the loaf if your oven does not bake evenly. Finish baking at high heat
until the crust is the color you want. Skip this step if you like a softer
crust.
In search of the Tall Crusty Loaf,
Greg in Petoskey