What's protecting my homemade bread from mold?

May 9, 2006 6:53 AM

What's protecting my homemade bread from mold?

I've started baking various kinds of bread (working mostly from the Hensberger Bread Bible). The white breads, if they last that long without getting eaten, tend to get moldy after about 5-6 days.

But one particular kind of whole wheat has lasted well over 8 days without developing any kind of mold on it, despite being moister and denser than the whites. I keep it (like the others) loosely wrapped in a plastic shopping bag on the counter.

The ingredients:
water, yeast, light brown sugar, molasses, whole wheat flour, grapeseed oil, cornmeal, salt, eggs, white flour, cooked wheat berries.

Is it the molasses? I've heard that they may have antifungal properties, but I can't find a source for that. Other suggestions for why?

On a related note, what other ingredients (that one might add to a homemade loaf) act as natural preservatives?

Please, no suggestions on alternate storage methods for preservation.

posted by Caviar to Food & Drink (15 answers total)

Is it sulphured or unsulphured molasses? Sulphured molasses has sulfur dioxide as a preservative, and that might confer some preservative benefits to your bread.
posted by headspace at 7:06 AM on May 9, 2006

Back when Brownberry was a hard-to-find niche brand, I remember hearing that they used vinegar in their loaves instead of artificial preservatives.
posted by notsnot at 7:06 AM on May 9, 2006

Could just be dumb luck. If you're really curious, I'd suggest baking up a whole bunch of variations and exposing them to fungal spores.

Honey is supposed to be antifungal, amongst other things.
posted by Leon at 7:10 AM on May 9, 2006

(Thought: wouldn't anything seriously antifungal kill off the yeast, too?)
posted by Leon at 7:14 AM on May 9, 2006

Sourdough bread seems to last much better than does non-sourdough. I'm not exactly sure why this is, but I think I've read some microbiology stuff that would support it. It's been a while since I've read most of that stuff, I mostly just bake now. I like Nancy Silverton's book on sourdough as a good place to start and learn the basics.
posted by OmieWise at 7:19 AM on May 9, 2006

(Thought: wouldn't anything seriously antifungal kill off the yeast, too?)

I get better results from my yeast when I proof it with honey than I do with anything else, so yeast must be immune to honey's anti-bacterial, anti-microbial effects.

Or I have mutant yeast... muahahahahah!
posted by headspace at 7:28 AM on May 9, 2006

Concentrated honey is an antimicrobial, mostly due to its low moisture content. If you dilute honey enough to brew or bake with it, it can grow fungi (including yeast), bacteria, or anything else that eats sugar.
posted by nebulawindphone at 8:20 AM on May 9, 2006

(Sulphur, on the other hand, is an antimicrobial even at low concentrations. Store-bought brewers' or bakers' yeast has been specially bred to be sulphur-resistant; sulphured fruit or molasses will kill off wild yeast.)
posted by nebulawindphone at 8:22 AM on May 9, 2006

The legendary alcoholic beverage mead is made by fermenting dilute honey.
posted by Steven C. Den Beste at 8:22 AM on May 9, 2006

I notice a significant difference in how rapidly my store-bought bread molds if I am careful to reach in with only clean hands and not touch any slices I'm not removing. This may not be real helpful with regards to home-baked stuff you have to take out and slice...
posted by phearlez at 8:59 AM on May 9, 2006

Most commercial flour has one or more preservatives such as calcium propionate and/or sodium benzoate and anti-caking additives, tricalcium phosphate. Vegetable oils usually contain a certain amount of mixed tocopherols, which are also a natural preservative. Whole wheat flours, because they contain high levels of wheat germ and its associated oils, go rancid on the shelf quickly, so often these type flours have higher levels of preservatives to give them decent storage characteristics. You can get stone ground whole wheat flour without any added preservatives or enrichment (vitamins such as riboflavin are normally added to bread flour as a public health measure, like iodine is routinely added to table salt). But taking out the preservatives doesn't do anything (scientifically speaking) to improve the flavor or "digestability" of the bread, and it will make your bread (and by extension, your kitchen) a haven for potential nasty mold spores....
posted by paulsc at 10:00 AM on May 9, 2006

I've been wondering about this myself. Julia Child mentions in The Way to Cook

"A starter, which you may also use in the same way for French bread dough, gives the loaf not only a pleasantly moist texture but superior keeping qualities as well."

She doesn't explain why, but maybe it has something to do with the fermentation process? I've noticed when I use a starter, even if it's only been sitting for 3 or 4 hours, my bread stays mold-free for around a week. This is true whether it's just a salt/flour/yeast French bread or a honey&wheat loaf, so I don't think it has to do so much with the ingredients as it does with the way the yeast is treated.
posted by maryh at 11:27 AM on May 9, 2006

Would crust thinkness or something like that have anything to do with it? You didn't say whether you had cut it yet, or not...
posted by catkins at 12:05 PM on May 9, 2006

Response by poster: A few clarifications, then.

1) Not sure if the molasses are sulphered or not - I'll have to check that.

2) The whole wheat flour is freshly ground from an actual water mill, so preservatives unless it's something that was in the wheat beforehand.

3) This has happened on two loaves in a row, not just once. Could be coincidence, but I made a loaf of white in the middle, and that one did get a bit moldy.

4) The loaves stayed unmoldy cut.

5) Yes, I could do some experiments. But since each loaf takes about 4 hours to make, and then 8 days or so to sit, this would probably take more space and time than I have available for this project.
posted by Caviar at 2:19 PM on May 9, 2006

I keep my bread in the refrigerator, because it never molds.
posted by Steven C. Den Beste at 6:41 PM on May 9, 2006