Pro tip: check your oven thermometer every 6 months, mine was off by 45 degrees
I baked two loaves of sourdough in my kitchen in Tulsa on Sunday, one with my old thermometer and one with a $12 replacement I grabbed that morning. The first loaf came out pale and gummy in the middle, the second one had a beautiful rise and a hollow thump on the bottom. When I checked the old thermometer against the new one in boiling water, it read 167 degrees instead of 212. Six months of flat bread and I blamed my starter the whole time. If your bakes have been off lately, drop your thermometer in boiling water and see what it says.