Reheating Reverses Staling

As long as much of the water released by the starch granules remains in the surrounding gluten—that is, as long as the loaf isn’t too old, or has been wrapped and refrigerated—staling can be reversed by heating the bread above the gelation temperature of wheat starch, 140°F/60°C. Once more the crystalline regions are disrupted, water molecules move in between the starch molecules, and the granules and amylose gels become tender again. This is why toasting sliced bread makes the interior soft, and why a loaf of bread can be refreshed by heating it in the oven.