Do you store your bread in the refrigerator or on the shelf? Bread stored at room temperature may grow mold sooner, but bread in the refrigerator gets stale faster.
Staling in bread is not only a matter of drying out; it is actually a reversal of some of the chemical changes that turned the dough into bread in the first place.
What Happens In The Oven?
When dough is heated in the oven, microscopic starch granules open up and absorb water. At room temperature, the starch molecules cling to each other in tiny, hard granules.
But as they warm up in the oven, the molecules move apart and the starch granule absorbs water. The larger, moister starch granules are softer and more flexible, giving bread its soft, slightly moist consistency.
When Bread Cools...
But as the bread cools, the starch molecules begin to return to their original tight granules, and in the process, expel the water that they absorbed during baking. As the starch granules contract, they get hard again and less flexible, making the bread dry and crumbly.
Cooler temperatures cause the starch granules to contract faster, while warmer temperatures allow the granules to hold their water longer. In the freezer the process of becoming stale is almost stopped, but just above freezing, bread gets stale the fastest.
How Do You Get The Freshest Bread?
So for the freshest loaf, either freeze your bread quickly or keep it at room temperature.
Bread that goes stale in a plastic bag doesn't really lose its moisture and can be improved by toasting. This is because the heat of the toaster causes the starch granules to reabsorb some of the moisture lost as the bread was becoming stale.