# Chemists:  A way to prevent the layer of skin from forming over hot chocolate?

**URL:** <https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338>\
**Category:** Factual Questions\
**Created:** [November 30, 2004, 3:58pm UTC](https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338 "2004-11-30T15:58:56Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![alterego](https://avatars.discourse-cdn.com/v4/letter/a/6bbea6/32.png) [@alterego](https://boards.straightdope.com/u/alterego)\
**Post date:** [November 30, 2004, 3:58pm UTC](https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338/1 "2004-11-30T15:58:56Z")

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Do you know a way? Perhaps a dash of salt, or, a dash of something would prevent it from forming? I prefer coffee, but a good friend would be unduly grateful if I surprised her with a remedy.

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**Author:** ![alterego](https://avatars.discourse-cdn.com/v4/letter/a/6bbea6/32.png) [@alterego](https://boards.straightdope.com/u/alterego)\
**Post date:** [November 30, 2004, 4:03pm UTC](https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338/2 "2004-11-30T16:03:16Z")

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PS: What are the components of milk and what does the layer consist of? Is it simply cooked hot chocolate at the top? If this is the case, would sprinkling some ice crystals on top before you nuke it help?

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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:** [November 30, 2004, 5:18pm UTC](https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338/3 "2004-11-30T17:18:12Z")

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> [@alterego](#):
>
> Do you know a way? Perhaps a dash of salt, or, a dash of something would prevent it from forming? I prefer coffee, but a good friend would be unduly grateful if I surprised her with a remedy.

It is the same skin that forms on milk alone when it is overheated. Not sure but probably due to oxidation. Microwave till HOT but not too hot. Will skin over near boiling point.

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [November 30, 2004, 5:44pm UTC](https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338/4 "2004-11-30T17:44:04Z")

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> [@spingears](#):
>
> Not sure but probably due to oxidation.

More likely, the skin is a layer of denatured milk proteins, just a tangled mess, not an _oxidized_ tangled mess. As you say, the trick to avoiding it is not to overheat the milk.

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**Author:** ![CrazyCatLady](https://avatars.discourse-cdn.com/v4/letter/c/dfb087/32.png) [@CrazyCatLady](https://boards.straightdope.com/u/CrazyCatLady)\
**Post date:** [November 30, 2004, 6:53pm UTC](https://boards.straightdope.com/t/chemists-a-way-to-prevent-the-layer-of-skin-from-forming-over-hot-chocolate/277338/5 "2004-11-30T18:53:01Z")

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If you’re doing stove-top, never turn your heat above medium, stir frequently, and make sure you turn off the heat as soon as it’s hot enough to drink. If you’re doing the microwave, use a lowish setting, stir frequently, and take it out as soon as it’s hot enough to drink.

You should always add just a tisch of salt to homemade hot chocolate, anyway–it helps bring out the chocolate flavor.