# How to guarantee your bread won't get moldy
**URL:** https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490
**Category:** Miscellaneous and Personal Stuff I Must Share
**Created:** [March 3, 2019, 4:23pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490 "2019-03-03T16:23:01Z")
**Posts on this page:** 15
**Page:** 1
### Author:  [@Shoeless](https://boards.straightdope.com/u/Shoeless)
#### Post date: [March 3, 2019, 4:23pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/1 "2019-03-03T16:23:01Z")
Use it in a science experiment.
My 10 year old granddaughter’s class was given an assignment at the beginning of the semester for a science fair experiment. For her project, she decided she wanted to test the effect of temperature on mold growth in bread. So we’ve been trying to help her grow mold on bread at various temperatures: cold (in the garage), room temperature, and warm (under a heat lamp).
Suffice it to say, we’re on our third or fourth iteration of trying to grow moldy bread since early January, with no success. However, the bread I took out of the bread drawer this morning to make toast had mold all over it. :smack:
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### Author:  [@running\_coach](https://boards.straightdope.com/u/running_coach)
#### Post date: [March 3, 2019, 4:27pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/2 "2019-03-03T16:27:40Z")
Is her bread out in the open or enclosed in a bag or other container?
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### Author:  [@Shoeless](https://boards.straightdope.com/u/Shoeless)
#### Post date: [March 3, 2019, 4:35pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/3 "2019-03-03T16:35:24Z")
The science fair bread has been kept in zippered sandwich bags so that it doesn’t dry out.
The bread that was in the bread drawer was just whole grain sandwich bread in the wrapper it came in.
It’s not unusual for bread (or hamburger buns) in our bread drawer to get moldy after a week or so. So I didn’t think it would be so hard to intentionally try to grow moldy bread!
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### Author:  [@running\_coach](https://boards.straightdope.com/u/running_coach)
#### Post date: [March 3, 2019, 4:40pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/4 "2019-03-03T16:40:41Z")
> [@Shoeless](#):
>
> \*\*The science fair bread has been kept in zippered sandwich bags so that it doesn’t dry out.
> \*\*
> The bread that was in the bread drawer was just whole grain sandwich bread in the wrapper it came in.
>
> It’s not unusual for bread (or hamburger buns) in our bread drawer to get moldy after a week or so. So I didn’t think it would be so hard to intentionally try to grow moldy bread!
Kept closed or opened on a regular basis?
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### Author:  [@elbows](https://boards.straightdope.com/u/elbows)
#### Post date: [March 3, 2019, 7:14pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/5 "2019-03-03T19:14:27Z")
Putting my store bought dinner rolls into an additional (ziplock) bag, when I get home, generally doubles the time it takes before they start to mould.
My guess is the zip lock keeps out a LOT more air than the bag it comes in. Should have left it in the kind of bag it comes from the store in, I think!
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### Author:  [@CannyDan](https://boards.straightdope.com/u/CannyDan)
#### Post date: [March 3, 2019, 7:15pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/6 "2019-03-03T19:15:32Z")
Perhaps your bread drawer has a dusting of mold spores that infect new breadstuffs kept within. Your controlled (sealed sandwich bags) breads may be pretty sterile. It may be useful to ‘infect’ your experimental breads by either leaving them exposed on the countertop for a few hours, or similarly put into your bread drawer, before packaging them and moving them to temperature controlled environments.
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### Author:  [@DorkVader](https://boards.straightdope.com/u/DorkVader)
#### Post date: [March 3, 2019, 8:17pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/7 "2019-03-03T20:17:13Z")
What CannyDan said plus your bread drawer might have air moisture a percent or two higher, just enough to encourage growth.
Had a pantry cabinet once, had the same problem with bread.
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### Author:  [@markn\_1](https://boards.straightdope.com/u/markn_1)
#### Post date: [March 3, 2019, 9:02pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/8 "2019-03-03T21:02:57Z")
This could actually be an awesome science lesson. She started with the idea for one experiment, determining the temperature sensitivity of mold growth, and accidentally made another discovery, mold spores don’t penetrate plastic bags. You might consider changing directions and seeing what kind of containers prevent mold growth: plastic bags, paper bags, glass jars with loose lids, glass jars with tight lids, etc.
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### Author:  [@Shoeless](https://boards.straightdope.com/u/Shoeless)
#### Post date: [March 3, 2019, 9:30pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/9 "2019-03-03T21:30:34Z")
> [@elbows](#):
>
> Putting my store bought dinner rolls into an additional (ziplock) bag, when I get home, generally doubles the time it takes before they start to mould.
>
> My guess is the zip lock keeps out a LOT more air than the bag it comes in. Should have left it in the kind of bag it comes from the store in, I think!
Yeah, I wondered if maybe the zipper bags were a little _too_ airtight. We wanted to keep the bread from drying out, but probably kept the mold out too.
> [@markn\_1](#):
>
> This could actually be an awesome science lesson. She started with the idea for one experiment, determining the temperature sensitivity of mold growth, and accidentally made another discovery, mold spores don’t penetrate plastic bags. You might consider changing directions and seeing what kind of containers prevent mold growth: plastic bags, paper bags, glass jars with loose lids, glass jars with tight lids, etc.
This would be an excellent idea, if not for the fact that her project is due Thursday. 😉
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### Author:  [@Icarus](https://boards.straightdope.com/u/Icarus)
#### Post date: [March 4, 2019, 2:44pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/10 "2019-03-04T14:44:30Z")
Just FYI - most commercially produced bread products contains a mold retardant [calcium propionate](https://bakerpedia.com/ingredients/calcium-propionate/). So, if you are over a certain age, your experience with bread getting moldy years ago would not be a useful metric nowadays.
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### Author:  [@kayaker](https://boards.straightdope.com/u/kayaker)
#### Post date: [March 4, 2019, 3:12pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/11 "2019-03-04T15:12:51Z")
> [@Icarus](#):
>
> Just FYI - most commercially produced bread products contains a mold retardant [calcium propionate](https://bakerpedia.com/ingredients/calcium-propionate/). So, if you are over a certain age, your experience with bread getting moldy years ago would not be a useful metric nowadays.
Yep. The young scientist should start with bread she has made herself.
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### Author:  [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)
#### Post date: [March 5, 2019, 3:05am UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/12 "2019-03-05T03:05:46Z")
Living in a high humidity environment, I can attest that mold spores think nothing of ziplock bags.
We make our own bread and it only takes a couple of days for it to get moldy.
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### Author:  [@glee](https://boards.straightdope.com/u/glee)
#### Post date: [March 5, 2019, 6:36am UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/13 "2019-03-05T06:36:34Z")
I keep my bread in the freezer and it doesn’t get moldy.
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### Author:  [@fedman](https://boards.straightdope.com/u/fedman)
#### Post date: [March 5, 2019, 9:12pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/14 "2019-03-05T21:12:19Z")
> [@elbows](#):
>
> Putting my store bought dinner rolls into an additional (ziplock) bag, when I get home, generally doubles the time it takes before they start to mould.
>
> My guess is the zip lock keeps out a LOT more air than the bag it comes in. Should have left it in the kind of bag it comes from the store in, I think!
did you mean “mold” (fungus) rather than “mould” (shape)?
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### Author:  [@Teuton](https://boards.straightdope.com/u/Teuton)
#### Post date: [March 5, 2019, 10:00pm UTC](https://boards.straightdope.com/t/how-to-guarantee-your-bread-wont-get-moldy/830490/15 "2019-03-05T22:00:24Z")
> [@fedman](#):
>
> did you mean “mold” (fungus) rather than “mould” (shape)?
The UK spelling of both is the same - mould.