The gummy line at the bottom of a sandwich bread or pan loaf is fundamentally about gravity — the crumb structure sinks downward. This can be avoided with a quicker heat-set of the structure, different shaping, and fermentation timing.
Some strategies to avoid it include:
- Bake on a lower shelf to get heat into the bottom of the bread faster, to set the structure faster.
- Place a baking stone or steel on the lower shelf of your oven to act as a heat sink, and bake the tin directly on it. Make sure the oven preheat is long enough to fully heat the stone/steel.
- Remove the bread from the tin for the last 10 minutes of the bake.
- Cool the bread on alternating sides to prevent it from sinking like a souffle.
- Try a shape that has more upward and spiraling tension, such as the rolled lobes of the this hokkaido milk bread.
- Experiment with a more extensive bulk and less extensive final proof, and vice versa.
