I've been exploring sourdough baking, as a lot of people have, and appear to struggle with the proofing prior to baking. I'm using a gluten free recipe (I have a wheat allergy), so I know that might throw a wrench into the troubleshooting aspect, but I trust the recipes. The basic technique is a little unconventional compared to other sourdough methods I am familiar with. I made a starter in the usual way, but the book requires converting the liquid starter (100% hydration) into a "mother starter", which has the consistency of pizza dough. For every recipe, you mix the mother starter with some water and fresh flour and let that rise until it doubles in size. This always doubles nicely in about 8 hours for me. Then, you mix that fed starter with the rest of the ingredients in the recipe. In this case, I made a pumpernickel bread which includes sorghum syrup, honey, cocoa powder, gluten free bread flour mix (again, I don't think this is the issue, as I've made bagels and pizza from this book, and those do fine), but I see the same under proofing issue with simpler breads from the book. Once the starter is incorporated to the rest of the ingredients, the dough is allowed to undergo its bulk rise in the fridge for at least 12 hours, and up to two days. After the bulk, you shape the dough and allow it to proof prior to baking. This time, I left the bread for 3 hours before baking, sitting on the preheated oven covered with oiled plastic wrap. It did grow in size, but apparently not enough, and smelled like active sourdough starter when I thought it had finished rising.

Interior crumb

Top

ok side

bottom

bad side

uncut side

The temp of the air on the oven is around 75ºF (I've checked with a thermometer), I've tried covering with oiled plastic wrap and floured tea towels, neither seem to work better or worse. This time I proofed for double the recommended time, should I just let it proof all day? Again, I know being gluten free brings in some unknown variables, but double the proofing time in the book seems extremely excessive.