My partner works at a restaurant where they serve sourdough as the bread you snack on to tide you over while perusing the menu. They are closed Sundays, which means any leftover bread on Saturday evenings goes home with the employees (since it can't be sold as day-old at the adjacent bakery the next day, as with other days). This means my partner frequently comes home with five or so loaves of sourdough.

Occasionally she'll also end up with a loaf or two of a different sort of bread. A nice wheat, or this particular bread full of nuts and herbs that they make.

It takes a long time for two of us to get through five large loaves of bread, so when she brings them home they go straight into Ziploc bags to keep them as fresh as possible for as long as possible. The sourdough loaves last positively forever (albeit with a little bit of loss of texture), but the wheat loaves or nutty-herby-loaves-I-forget-the-name-of always end up with mold spots after five days to a week.

I know nothing about sourdough bread other than that it tastes delicious. Is it more resistant to molding than other types of bread?

  • 3
    Hmmm, interesting question. We've got some real experts on the subject so I'm sure you'll get a good answer. Can you make room in your freezer? If you can, it's best to freeze bread that you won't eat within a couple of days.
    – Jolenealaska
    Sep 16, 2014 at 5:16

3 Answers 3


The short answer is yes, sourdough breads are generally more resistant to fungus due to the fermentation process of the sourdough starter. The reasons for this are only now becoming understood. This study from the Journal of Applied and Environmental Microbiology says:

Sourdough is different from traditional bread because it takes an extra fermentation step, which uses lactic acid bacteria to metabolize sugars and add that particular spunky flavor. The researchers found that during sourdough production, lactobacilli bacteria convert another acid found in bread flour--linoleic acid--into hydroxy fatty acids that resist fungus.

So there you have it, it's possibly better for you, tastes good (I think so), and lasts longer without going moldy.

  • 8
    Am I the only one that sees some irony in the statement 'Sourdough is different from traditional bread...'?
    – Max
    Sep 17, 2014 at 15:17
  • That is a good point!
    – GdD
    Sep 17, 2014 at 20:22

From personal experience, the "anti microbial properties" of sourdough diminish depending on the moisture content of the bread. The type of flour and hydration of the dough impact this.

I've made "all white" and "30-60% [of flour content] wheat bran" breads using sourdough starter and long (overnight) bulk fermentation.

The wheat/oats tend to hold on to more moisture in the final result and those were the loaves that showed mold the quickest.

Experimenting with low (65%) and high (80%) hydration had very little impact on the "all white" loaves. However, it was different with wheat bran/oats. The low quantity wheat bran and low hydration loaves lasted about a week. The high quantity wheat bran high hydration loaves molded in less time.

The high quantity high hydration wheat bran loaf was preferable (to my test subjects - friends and family) because it wasn't so "rough and dry" (their feedback) as the lower hydration wheat bran loaf.


Firstly, some people call a bread 'sourdough' if they simply use a starter of previously fermented dough. However most people who know a little about sourdough use the term to refer to a bread made from a started fermented by a naturally available combination of wild yeast and Lactobacillus. You can make your own culture or purchase them from lots of suppliers on the web.

I've made both types of bread and the 'proper' sourdough is a very different in how it 'degrades'. I save my stale bread to make 'bread pudding' and Often use sourdough bread that is weeks old and I mean 6 or 8 weeks old. By this time the bread is as dry as a crisp and never had a spot of visible mould on it. So I would say a big fat yes.

Additionally; I suffer from ulcerative colitis and find that 'normal' commercial bread eaten in anything but small occasional quantities makes my condition a lot worse. My home made sourdough has the complete opposite effect; the more I eat the better I feel. I now see it as being as important as any of my drug (which I still take in reduced quantities).

I put this affect down to an ant-microbial/anti-fungal activity from the bread but I obviously have no direct scientific proof.

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