Bread Goes Stale About Six Times Faster in the Refrigerator than at Room Temperature

Scott 37
Today I found out bread goes stale about six times faster in the refrigerator then when kept at room temperature.

On the surface, this might seem counter intuitive; after all, everyone knows if you want to keep food fresher longer, you put it in the fridge.  The problem stems from what bread is made out of, specifically starch molecules, and how those starch molecules react in certain conditions.

Before we begin to dissect why bread goes stale faster in the fridge, it’s important to know what bread is actually made of.  Breads are essentially networks of wheat flour protein molecules (called gluten) and starch molecules.  Suspended in this network of molecules is carbon dioxide that is produced by the fermentation of yeast inside the dough. This gives bread its fluffy foam-like texture.  Begin to play around with the amounts of these ingredients and other fancy tasting additives and you can get many different types of textures and tastes.

The starch inside of this mixture has its own characteristics.  Starch molecules are made of two base components, both are long chain sugar molecules.  Glucose (sugar) is classified as a monosaccharide, meaning one glucose unit. But if you link these units together, they can become a polysaccharide or complex carbohydrate (be afraid Atkins lovers, be very afraid).  The two units are Amylose and Amylopectin. Amylose, which usually consists of about 10,000 sugar units, is built like a narrow bundle of reeds with all its glucose units arranged in straight parallel lines.  Amylopectin, which usually consists of about 20,000 glucose units, have a more tree-shrub like appearance with its glucose units clumped together going in all directions.  Plant starch is typically 20-30% amylose and 70-80% amylopectin.

When heated up in the presence of moisture or water molecules, for instance placing the bread dough in the oven, the starch molecules weaken and allow water molecules to enter, or get in between the chains of the sugar molecules and join with them.  This swells the starch granule and begins to soften it up, making it oh so warm and squishy!  In the case of bread dough, the moisture can come from two sources, either the wheat protein in the bread itself or the water added to the mixture that makes up the dough.  Once cooling begins, aka; the moment you take it out of the oven, the process begins to reverse itself and the starch molecules begin to “dry out” or crystallize and harden again, a process known as retrogradation.  Thus, the slow process that makes croutons what they are begins (thank you Outback Steakhouse, thank you!)  Another example of a similar process in food can be observed by leaving honey uncovered on the counter.  Over time, it would dehydrate and all you would be left with is pure granules of hard white glucose molecules (sugar crystals).

So then why does this retrogradation process occur more rapidly in the refrigerator?   Although scientists have made considerable progress in dissecting the staling process, it still is not yet wholly understood.  The leading theory is that the dehydration reaction, condensation, is the main mediator in the dehydration process in this case.  Whatever the mediator, the cause of the staleness is the same; water molecules detach themselves from the starch molecules and the starch molecules begin to take their original shape and harden again.  The cool temperatures of the refrigerator make the dehydration process happen more quickly, specifically, about six times as fast via the process listed above.  This is why fruit and vegetables can last longer in the refrigerator.  In their case, the dehydration process slows the natural degradation caused by the presence of water molecules.

Bonus Facts:

  • The hard outer crust of the bread was initially the only method available by bakers to keep the moisture content in bread, thus keeping it fresh longer.  Current methods by large scale bread bakers involve using artificial ingredients that slow the natural dehydration process. Thus, most widely manufactured bread will mold long before staling ever occurs.
  • In a cruel twist of fate, the presence of moisture will keep the bread from becoming stale; however, the same moisture will allow mold spores to propagate quicker.
  • The world’s first automatic bread slicer was invented by Otto Frederick Rohwedder in Davenport, Iowa.  He first built a prototype of his bread slicer in 1912.  Unfortunately, his blueprints and machine were destroyed in a fire in 1917.   From there, he struggled to obtain funding to begin again on his machine as the idea of pre-sliced bread was not at all popular among bakers.  They felt the reduction in shelf life of the bread would not be popular among consumers, even if it was reasonably well packaged to try to delay the inevitable accelerated staleness as much as possible.  Eventually, in 1927, Rohwedder was able to re-build the machine and produce a model ready to use in an actual bakery.
  • In order to get around the “staleness” problem, Rohwedder initially tried to hold the pieces of bread together after slicing with pins.  The pins would then be removed when you wanted a slice.  This didn’t really work out for a variety of reasons and he eventually simply modified his machine to wrap the sliced loaves in wax paper directly after slicing.
  • French toast is traditionally made out of stale bread.  Bread has been a staple food for most cultures since food first began being prepared and, up until very recently, the vast majority of humans would have never dreamed of wasting any food; thus, one has to find a way to make stale bread palatable.  Soaking it in milk and egg and then cooking it, seems logical enough, making a good tasty meal while not wasting any bread.

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37 Comments »

  1. Angel August 17, 2011 at 2:13 pm - Reply

    Wow, I had no idea. However, I eat bread that has no artificial ingredients, so I keep in in the fridge to prevent it from molding in just a few days. It still tastes great!

  2. Bobba August 18, 2011 at 3:47 am - Reply

    Not the case if you live in a tropical region, the bread will have fungus on it within a day or two if it’s not put inside the refrigerator. Thanks for the heads-up though!

  3. JohnS August 18, 2011 at 5:00 am - Reply

    I have always kept home-made and store bread in the fridge. My experience is that, if kept in a sealed bag, the bread retains freshness for up to two weeks there, as opposed to a week on the counter, at best.
    10-15 seconds in the microwave makes it almost good as fresh-made!

  4. orionsune August 18, 2011 at 6:17 am - Reply

    Interesting, I store bread in the icebox and it lasts much longer than if I stored it at room temp.

  5. Lisa B August 18, 2011 at 7:53 am - Reply

    But bread goes all moldy way faster out on the counter than in the fridge.

    • Ed March 21, 2014 at 8:49 am - Reply

      I have a bread box, not as cool as the frig but dark, light must contribute to mold’s life.

  6. Dr. Awesome August 18, 2011 at 9:36 am - Reply

    What about the freezer? Does it cause bread to go stale faster than the fridge? Or does freezing hold the water in place within the starches?

  7. mde1138 August 21, 2011 at 8:45 pm - Reply

    Presumably the article refers to bread products not kept in plastic bags.

  8. Emperor Toro August 22, 2011 at 9:36 am - Reply

    Here in the Phoenix area, food mold can grow fast enough to watch. So, in our house, we keep bread in the fridge and then take it out 20 minutes before we plan to eat. For us it’s the best and most reasonable solution for fresh bread that lasts more than 3 days..

  9. Christopher Bird August 22, 2011 at 10:30 am - Reply

    I bake my own bread – using just flour/water/yeast/salt. When I make a bread with a “sponge” – i.e. some prefermented dowgh, it takes a lot longer to grow mold. I do keep my bread out, on the counter and not wrapped in a plastic bag. It does dry out a tiny bit – at the crust, but the inside stays good for several days. It molds faster in plastic, though.

    I bake on Sundays, Tuesdays and Thursdays, so I don’t have stale bread around for long. At this time of the year, I do it on my grill outdoors so I don’t heat the kitchen.

    I have never found the need to refrigerate bread (living in Dallas, TX – day time kitchen temp is about 82F). But then I don’t refrigerate butter either – I do keep it in a “butter bell” with – at least at the beginning of the day some iced water. The butter stays spreadable and the water/butter barrier prevents the butter from going rancid. It does get a little more soft than I would like though if I forget to refil the bell occasionally with iced water.

  10. Dave August 23, 2011 at 3:41 pm - Reply

    Any benefit of freshness here is lost on mold development in humid climates.

    Also weather or not you are using shelf chemical breads, store bakery bread or homemade bread with without preservatives will play a factor.

    I never use the fridge, it is ether counter for short term or freezer for long term.

  11. Kay January 16, 2012 at 9:24 pm - Reply

    In my long experience, storing bread in the fridge does indeed extend its useful life. Like another poster, my home is in a tropical climate.

  12. David W September 18, 2012 at 7:53 am - Reply

    I think that it is a matter of whether you want to avoid bread going stale or mouldy. One answer is to taost the old bread from the fridge and toss the mouldy bread from the counter.

  13. Havokmon May 9, 2013 at 8:48 am - Reply

    Put the bread in the fruit/veg drawer. It’ll keep much longer than on the counter, and won’t get stale as fast as if you just put it on a shelf.
    We usually buy multiple loaves of bread on a single trip to the store, and they’ll keep up to a month.

  14. David May 10, 2013 at 1:21 pm - Reply

    read the title and thats it but bread does not go stale faster at all in the fridge. My bread last about 6 times longer…

    • Daven Hiskey
      Daven Hiskey May 10, 2013 at 10:47 pm - Reply

      @David: So to some up your viewpoint “Read the title and decided I’m uninterested in reading viewpoints and evidence that go against my preconceived notions.” ;-)

  15. Dori.jeff May 28, 2013 at 11:41 am - Reply

    Since I live alone, my preference is to keep bread in the freezer and take out one or two slices, as needed, and drop in toaster! This works great for me! No stale taste and NO mold!
    I totally enjoy your articals, keep them coming!!!

  16. Will July 30, 2013 at 2:05 am - Reply

    Whatever the science, it doesn’t tally with my experience of storing sliced bread in the fridge. It maybe it goes a little stale, but it lasts for weeks as toasting bread in the fridge, as opposed to days on the counter and it’s okay for sandwiches for at least a week. Mould is much worse than a little staleness.

  17. Bobby September 13, 2013 at 6:05 pm - Reply

    This is a load of crap. When we started keeping bread in the fridge, it lasted one or two months past the “sell by” date and still tasted fresh.

  18. LOVEPAREEK September 28, 2013 at 4:56 am - Reply

    DEAR SCOTT…I HATE 2 DISAGREE WITH U, BUT PRACTICALLY SEEN, BREAD GOES LONGER IN FRIDGE. WITH ALL MY DUE RESPECTS, SIR.

  19. Yer Pal October 25, 2013 at 6:04 am - Reply

    Do all TIFO readers live in the tropics? Jeez. I live in a frozen shithole… Bread lasts for years.

  20. J.Jerome. November 22, 2013 at 12:07 pm - Reply

    I found this site, having read on the wrapping to a bought loaf of bread, that one ‘shouldn’t’ keep it in a refrigerator, because I wanted to know why?
    Having read the suggestion as to why it should not be kept in a fridge, I personally have to say that I totally disagree. I’ve kept the bread that I buy in a fridge for years. I hasten to add, not the same loaf of bread you understand, but indeed, I’ve always kept bread and other similar goods in a fridge.
    My grandparents used to keep their bread in what was called a ‘safe’. Basically, a metal box with little perforations in the front and sides, and this was kept on top of the counter, so to speak. This of course was before refrigerators had even been invented. However, the bread, rolls, or cakes etc. that where kept in it would go mouldy within a couple of days if not eaten, whereas in my experience, when kept in a fridge, not only does the produce not go mouldy, but even more to the point, certainly doesn’t go stale.
    I can fully understand why one might think twice about freezing bread and similar goods. For when thawing it out, the ice melting would leave it very moist indeed, and it would be that extra moisture that would tend to make it turn mouldy in a short space of time, but as for keeping bread and the like in a fridge, as I say, in my experience, no problem, and it doesn’t lose it’s flavour either.
    Having said that, as the old saying goes, “Each to their own”.

  21. Kristen November 24, 2013 at 8:29 pm - Reply

    So when bread molds it’s a totally different process than when it goes stale (water molecules detatching from the starch molecules)?

  22. Linda March 11, 2014 at 11:40 am - Reply

    I bake almost everyday and would never keep my baked goods in a fridge however I do freeze them and take them out when needed. I hate seeing my hard work go stale or moldy. I don’t know why but the freezer works. I make kaisers, cinnamon rolls,bagels, , french breads, sourdough breads. I leave out in a airtight container just what we’ll use that day and freeze the rest, so they are ready to use and we have a variety.

  23. Ed March 21, 2014 at 8:55 am - Reply

    To bad the less bread you buy the more it costs. A 1lb loaf is to much for a single person to consume before it gets moldy.
    But bakeries don’t sell 1/2lb or 1/4lb loafs.

  24. Smien September 26, 2014 at 2:06 am - Reply

    I loved your article, it was really interesting! Wish my science classes had been like this. Living in a tropical country, bread from the supermarket lasts about 2 to 3 days out on the counter before going mouldy. In my case, if I put bread in the fridge, it does indeed turn hard and stale…..so needs toasting. If left for 8-10 days in the fridge, water droplets appear inside the plastic bag/container and bread finally gets mouldy. Best option for me is freezing- bread remains soft and fresh. But its such a hassle trying to separate a couple slices from the frozen stack when I want a sandwich immediately.

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