Stale bread

Stale bread is old bread, or rather, bread that is no longer fresh and hardened. More precisely, stale bread has a crust that is NOT crispier and apparently soft (due to the absorption of internal water), while the crumb is hard and crumbly to the touch.

It is a common opinion that, due to the exposure to dry air, the bread becomes stale due to the reduction of free water (AW - Activity Water), to the benefit of nutritional concentration, with an increase in overall caloric power.

However, several experiments carried out on whole-bread forms turned into stale bread showed a much lower level of dehydration than was desired; in this regard, there is reason to believe that the loss of water from stale bread does not contribute at all to the hardening process of fresh bread.

The first test was carried out by Jean Baptiste Boussingault in the mid-nineteenth century:

" Taking into consideration a round bread with a diameter of 33cm, a thickness of 14cm and a weight of 3, 760kg (detected at the time of baking), a thermometer was placed inside it, penetrating 7cm from the surface, which revealed a core temperature of just 97 ° C (despite having been baked in the oven at 250-300 ° C).

By placing the bread in a chamber at 19 ° C for 12 hours, at the heart, the bread has kept a temperature of 25 ° C and, only at the end of the 24 hours, it has reached equilibrium with the outside temperature.

At this point, noting an already partial transformation into stale bread, a second weighing of the food was carried out revealing 3, 730kg; dehydration was only 30g.

On the 6th day, with totally stale bread, a third weighing was carried out which revealed 3.690kg, highlighting a further dehydration of 40g which, added to the first, led to a total water loss of 70g on an initial bread of 3760g (1.86%).

Well, putting in the oven the 3.690kg stale bread for an hour (at high temperatures, reaching 70 ° C at the heart), there was a further water loss of 120g of water in conjunction with the total restoration of the bread freshness.

In a second experiment, the scientist sealed stale bread crumbs in an airtight tin (to avoid excessive dehydration) and noticed that, by heating it and cooling it indefinitely a number of times, the crumb continually restored and lost its elasticity characteristics ".

In conclusion, the bread becomes stale and returns to its original consistency based on temperature; by baking the whole, stale bread and subjecting it to heat it regains its original consistency, just as it leaves it at room temperature and undergoes a hardening process. All this can be repeated several times without significantly changing the hydration rate. Obviously, if "pieces" or "slices" of bread were to be used, the result would be, at least in part, different; the bread would not enjoy the external insulating coating of the crust and the dehydration could be more incisive (except for the experiment performed in hermetic closure).

In patica, it is not for the quantity of water that the stale bread differs from the fresh one, but due to a reversible molecular alteration of the starch (of colloidal nature) which: starts during the cooling, develops later, and persists until that the temperature does not exceed a certain limit (at least 70 ° C). It is however likely to assume that this structural evolution can also occur during the first digestion, altering the degradation of the complex carbohydrate and making it more or less available.

Rare Bread Videoricetta

How many times did you happen to buy some bread and go for some pieces? It often happens to me, but I always find a way to recover it: I can grate it, soften it in milk to prepare fish balls or dumplings or, again, soak it in vinegar to prepare the green sauce! Today, however, with the advanced stale bread I will prepare super-fast tasty pizzas for you!