I am not a super bread baker but do have lots of baking books. I understand that the hot water in the oven serves to make a hard crust and some recipies say it keeps the bread moist too. I do know that you shouldn't keep the water in for the whole baking time> The first time I tried putting water in the oven I was making a sourdough rye bread. I wanted a really crusty loaf so I left the water in for the whole baking time. The bread smelled wonderful but the crust was so hard that I couldn't cut the loaf!!