# Why is one side of aluminum foil shiny and the other less so?

**URL:** <https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577>\
**Category:** Factual Questions\
**Created:** [December 17, 2003, 6:27pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577 "2003-12-17T18:27:55Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\
**Post date:** [December 17, 2003, 6:27pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577/1 "2003-12-17T18:27:55Z")

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One side of the aluminum foil is shiny like a mirror while the other has more of a matte finish. Why is that? Does this difference have any practical advantages or drawbacks to watch out for?

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**Author:** ![Earthling](https://avatars.discourse-cdn.com/v4/letter/e/90db22/32.png) [@Earthling](https://boards.straightdope.com/u/Earthling)\
**Post date:** [December 17, 2003, 6:35pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577/2 "2003-12-17T18:35:21Z")

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The Master [speaks](http://www.straightdope.com/classics/a5_172.html):

> [@](#):
>
> The shiny side is shiny because of the way foil is made. During the last pass through the rolling mill, a double thickness of foil is run between the rollers. The side of each sheet that comes in contact with the polished steel rollers comes out shiny. The other side has a matte finish.

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**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\
**Post date:** [December 17, 2003, 6:35pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577/3 "2003-12-17T18:35:22Z")

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[The Master speaks](http://www.straightdope.com/classics/a5_172.html), noting that the shiny and matte sides are innocent byproducts of the manufacturing process and that either side can face te food or face the heat.

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**Author:** ![eman77](https://avatars.discourse-cdn.com/v4/letter/e/f04885/32.png) [@eman77](https://boards.straightdope.com/u/eman77)\
**Post date:** [December 17, 2003, 8:41pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577/4 "2003-12-17T20:41:13Z")

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Do you guys call each other and decide to post the same thing at the same exact time?

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**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\
**Post date:** [December 17, 2003, 8:50pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577/5 "2003-12-17T20:50:41Z")

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> [@](#):
>
> \*Originally posted by eman77 \*  
> \*\*Do you guys call each other and decide to post the same thing at the same exact time? \*\*

NO! Not Me.

On more than one occassion I have seen a new post, typed a short or fairly short response and when it comes up there are two or three that have replied in that short time. The probablility of this happening may depend on time of day and activity on the boards.

Seems strange doesn’t it, almost as it there were colusion.

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“Beware of the Cog” 🙂

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**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\
**Post date:** [December 17, 2003, 9:09pm UTC](https://boards.straightdope.com/t/why-is-one-side-of-aluminum-foil-shiny-and-the-other-less-so/219577/6 "2003-12-17T21:09:30Z")

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Shhh. Don’t let him know!