So steam is indispensable: there are no beautifully browned, crusty loaves without it. You should note that once the crust is formed in the oven, after about 15 or 20 minutes, the steam is no longer necessary, so there is no need to keep adding it for the rest of the cooking time.
Creating steam in the oven
Professional bakers have the advantage of a special "Steam" control on their electric ovens. This injects water into the oven, which lands on very hot metal elements and vaporises to create the steam. They simply press a button and “pshhhh!” , that's it.
For amateur bakers like us, things are rather different, but here are a few ways to achieve a similar effect:
Conventional kitchen oven
For this set up, preheat the oven with an empty
oven tray sitting directly on the
bottom (oven floor or sole) and leave it in the oven to heat up.
When you put the bread in the oven, before closing the door, pour a large glassful of water into the burning-hot tray (do be careful not to scald yourself),
then close the door quickly.
The water hitting the hot tray will vaporise and create the steam in the oven, just as required.
If all the water has evaporated in under 15 minutes, add a second glassful.
Bread oven
If you are fortunate enough to have a proper
bread oven, you will need to use a special technique, shown on this page which explains the
Steam Machine.
To sum up: Without steam, no beautiful, good bread. You need to have steam in the oven during the first 15 minutes of baking.