7
$\begingroup$

If I buy a loaf of freshly-made bread and leave it out at room temperature for a day or two, when I reach into the bag the air inside is much warmer than the rest of the room. Why?

$\endgroup$
  • $\begingroup$ Maybe there is some crystallization of organic molecules going on while the bread turns hard. This might be a chemical question after all. $\endgroup$ – tobias47n9e Oct 11 '12 at 8:10
  • $\begingroup$ After reading some more stuff I actually think that crystallization of starch might be the answer to this question. There is a lot of literature about this and it might very well be that it can be sufficiently exothermic to warm the small volume of air in a bag. $\endgroup$ – tobias47n9e Oct 11 '12 at 18:53
  • 1
    $\begingroup$ To the above point i also want to include possible exothermic enzymatic reactions by microorganisms also $\endgroup$ – Eka Oct 18 '12 at 15:31
  • $\begingroup$ It could also be that inside the bag it's humid, and purely through suppressing the slow evaporative cooling of your skin it "feels" warmer. You could put on a thin nitrile glove to control for that. $\endgroup$ – Nick T Oct 16 '16 at 22:48
  • $\begingroup$ (It turned out to be completely bogus, oops) $\endgroup$ – amara Oct 17 '16 at 4:15
8
$\begingroup$

After reading some more stuff I actually think that crystallization of starch might be the answer to this question. There is a lot of literature about this and it might very well be that it can be sufficiently exothermic to warm the small volume of air in a bag.

$\endgroup$
  • 6
    $\begingroup$ I call for an experiment. Bread, digital thermometer with recording device... $\endgroup$ – tobias47n9e Oct 14 '12 at 17:16
  • 1
    $\begingroup$ We need a controlled experiment before speculating. What sort of bread, bag, room? Moreover measure the temperature and don't rely on subjective feeling. $\endgroup$ – matt_black Dec 30 '16 at 11:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.