Reader Melody writes this about steaming loaves of bread:
Steaming honestly doesn’t seem to help that much. My baguettes still have a thick and dull crust. Am I doing something wrong? I spray more often than you do. If you can talk a bit about this that would be really helpful. I’ve been talking to our local baker but I think he’s getting a bit tired of me.
Melody, I would be delighted, for there are a lot of misconceptions about steaming bread. It’s widely thought that steam produces thin, crispy crusts on breads. That isn’t strictly true. What steam actually does is delay the formation of a thick crust by moistening the surface of the bread and keeping it supple. This allows the loaf to expand more than it otherwise would in a drier oven. The result is a higher rise and more open crumb since the crust doesn’t harden immediately and hold the expansion in. This is actually the main benefit of steam.
In an ideal situation, once the bread has finished “springing” — about a third of the way through the bake — you quit the steaming and allow the surface of the loaf to dry out. If all goes well, what would have otherwise been a thick and crunchy crust is now a thin and crispy crust.
A further benefit of the steam is that it causes flour granules on the surface of the loaf to absorb moisture, swell and “gelatinize” (read: dissolve into their component starch molecules). Those individual carbohydrate molecules will further break down in the heat of the oven into their component sugars, which them caramelize and turn the crust brown.
So that in a nutshell is what steam does. I should add that trouble starts when you introduce too much steam and/or keep it up for too long. In that case the cool, gelatinized layer gets too thick and the finished crust becomes extremely hard and thick. The prolonged cooling also retards caramelization and keeps the crust from browning.
So that’s probably what’s happening in your oven Melody: too much spritzing! The best of all possible worlds for bread making is a moderately moist oven for the first 20-30% of the bake, then an almost totally dry oven for the rest. Make sense? Thanks for the question!