# Why doesn't sugar rot? **URL:** \ **Category:** Factual Questions\ **Created:** [October 17, 2000, 10:05pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327 "2000-10-17T22:05:12Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![parkerea](https://avatars.discourse-cdn.com/v4/letter/p/a5b964/32.png) [@parkerea](https://boards.straightdope.com/u/parkerea)\ **Post date:** [October 17, 2000, 10:05pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/1 "2000-10-17T22:05:12Z")
Given that sugar is wonderful food, why is it that sugar in high concentrations – granular, powdered, honey, etc. – seems immune to bacteria? I have heard (rumor only) that jars of honey have been found in the pyramids, still intact. ---
**Author:** ![glee](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@glee](https://boards.straightdope.com/u/glee)\ **Post date:** [October 17, 2000, 10:10pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/2 "2000-10-17T22:10:48Z")
It’s not immune to ants - keep those jars sealed! ---
**Author:** ![cher3](https://avatars.discourse-cdn.com/v4/letter/c/da6949/32.png) [@cher3](https://boards.straightdope.com/u/cher3)\ **Post date:** [October 17, 2000, 10:13pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/3 "2000-10-17T22:13:55Z")
This is just to entertain you until someone scientific comes along, but I believe that a high concentration of sugar dehydrates the little bacteria critters. So it works for pretty much the same reason that preserving food with salt works. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [October 17, 2000, 10:22pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/4 "2000-10-17T22:22:51Z")
> [@](#): > > \*Originally posted by parkerea \* > \*\*Given that sugar is wonderful food, why is it that sugar in high concentrations – granular, powdered, honey, etc. – seems immune to bacteria? I have heard (rumor only) that jars of honey have been found in the pyramids, still intact. \*\* Not sure, but I do know this: plain 'ol, granular cane sugar that you buy at the super market has an _extremely_ low relativity humidity content. Seems I recall it was 0.02% RH or something. That’s why it lasts so long in your kitchen cabinet. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [October 17, 2000, 10:33pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/5 "2000-10-17T22:33:23Z")
WAG alert I don’t think dry sugar is particularly palatable to micro-organisms. In fact I’m trying to think of really dry anything that microbes like. So… I would guess the lack of water to make it absorbable (and microbe consumable) is what keeps it preserved. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [October 17, 2000, 10:42pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/6 "2000-10-17T22:42:07Z")
**astro** : I think you’ve hit upon it. Sugar requires water to dissolve in or else the sucrose stays in a form unsuited to cellular activity. That fact, combined with the dryness of Egyptian tombs, allows sugar from the Pharonic Era to come down to us fit for eating. We need some water to digest sugar as well, or else the concentrations in our blood go awry and we get thirsty. ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [October 17, 2000, 11:06pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/7 "2000-10-17T23:06:55Z")
I don’t think that’s it, Derleth. Honey can be used as a disinfectanct on a wound, and it surely is not without moisture. I heard it explained once, but damn if I can remember it. I have a vague feeling Cecil covered this once. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [October 17, 2000, 11:37pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/8 "2000-10-17T23:37:32Z")
I can assure you that the basic answer, for both granular sugar and honey, is that they contain very little water in relation to the sugar concentration (they are hygroscopic), and hence draw the water out of bacteria that come in contact, killing the little beasts. Of course if you dilute either sugar or honey enough, it will rapidly ferment. I hadn’t heard that about placing honey on a wound, but evidently the relatively slight dilution from the wound fluids isn’t enough to destroy honey’s hygroscopic properties. If you tried using a more dilute solution of honey, I think you’ld get one royal infection. Honey obviously contains some water, or it wouldn’t be liquid; but its concentration is higher than the cellular fluid of the bacteria, and that’s all that’s required. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [October 17, 2000, 11:53pm UTC](https://boards.straightdope.com/t/why-doesnt-sugar-rot/37327/9 "2000-10-17T23:53:30Z")
\>\> That fact, combined with the dryness of Egyptian tombs, allows sugar from the Pharonic Era to come down to us fit for eating I do not think the Egyptians had sugar. I think it was first manufactured many centuries later.