I just baked my first loaves of sourdough bread using Nancy Silverton's starter method. It turned out very nice and I could taste the sourness of the bread. The crumb was very open, which really pleased me, being a beginning baker. However, when the loaves went into the oven, the bottoms of the loaves split open. It's a very rustic looking loaf, so all is not lost. It kinda gives it character, but I don't think I want to reproduce it. LOL

Any feedback on why this happened? I couldn't find any info about this when I did a search. The only thing I did differently was use Saltillo tiles that I just purchased and seasoned yesterday.