I just found out that bread becomes stale not so much because it loses moisture, but because of a process called starch retrogradation. During the baking of bread, the starch in the flour gelatinizes — its granules absorb water, swell, and the structure becomes softer and more pliable. After cooling down and over time, the starch begins to reorganize into a more crystalline structure — this is retrogradation. Moisture indeed escapes, but not all of it and not necessarily to the outside. In the fridge, staling occurs faster precisely because of the accelerated retrogradation of starch at temperatures around 0–5°C.
Therefore, if you reheat stale bread (for example, in a toaster or an oven), the starch partially gelatinizes again, and the bread briefly regains its freshness. However, this effect is temporary. It doesn’t work the same way with French fries, where moisture is expelled more effectively, and the starch is slightly different. Hence, reheating does not break down the crystals without water, and the moisture has already left. The result is a rubbery, “styrofoam-like” texture, especially in fries that were fried in oil.
I’m going to fry some potatoes and eat them with bread
Hi, I'm Rauf Aliev. 