Check Oven Temperature Hidden among the above puns was what seems to be the best starting advice: check the oven temperature.
If you're having trouble with both yeast breads (sourdough) and baking powder breads (banana) falling, this points to your taking the breads out of the oven before they are baked firmly enough to hold their structure. Each kind can fall for other reasons, but if they are both falling, they probably aren't baked.
If your oven setting is in the 325-350 range and you are baking for the required amount of time, that shouldn't be happening consistently.
I suggest getting an accurate probe-style thermometer, or some other kind that you can easily see while the oven is running, and then set it at 350 and monitor the temperature periodically. It will rise and fall during this process; ovens don't keep an exactly constant temperature. But the fluctuation shouldn't be dramatic, the set temperature should be the mid-point of the fluctuations, and the oven should spend a good amount of time at the temperature it is set for. If those things aren't happening, the temperature control or the heating elements are not working right.
My mother was having a similar consistently-underdone-baking problem a while ago, and it turned out that one of the two heating elements that was supposed to be bringing her oven up to temperature didn't work most of the time. |