Slashing the top of a loaf with a wet dough
I am a newby to sourdough bread. Most or the recipes I have come across instruct the baker to cover the rising loaves with a damp cloth and to slash the top with a razor before baking.
Yesterday I had a couple of unbleached white flour loaves rise for nine hours, until they had risen to the top of their pans. They had that nice round shape on top. But they deflated once I cut into them and did not spring up that much during baking. I used an large exacto knife to cut, the sharpest knife I have.
Suggestions? Is it necessary to even slash the dough? I tried using a dry cloth instead. This makes for easy slashing but a tougher crust.