# Root Beer Foam

**URL:** <https://boards.straightdope.com/t/root-beer-foam/193003>\
**Category:** Factual Questions\
**Created:** [August 4, 2003, 11:28pm UTC](https://boards.straightdope.com/t/root-beer-foam/193003 "2003-08-04T23:28:26Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [August 4, 2003, 11:28pm UTC](https://boards.straightdope.com/t/root-beer-foam/193003/1 "2003-08-04T23:28:26Z")

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What makes root beer more foamy than other sodas? The suds seem foamy as opposed to the “fizzy” nature of other sodas (pops).

Isn’t all carbonation created equal?

- Jinx

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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:** [August 5, 2003, 1:56am UTC](https://boards.straightdope.com/t/root-beer-foam/193003/2 "2003-08-05T01:56:05Z")

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Natural detergents derived from desert plants supply the foamy head on root beer. Sarsaparilla was the source of these [saponins](http://lpi.oregonstate.edu/sp-su98/saponins.html) until the early 60’s, when the FDA declared that it contained too much carcininogec saffrole to be fit for human consumption. Now (see link) the detergents in root beer come from Yucca plants, or quillaja bark.

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**Author:** ![Tangent](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tangent/32/3098_2.png) [@Tangent](https://boards.straightdope.com/u/Tangent)\
**Post date:** [August 5, 2003, 5:49am UTC](https://boards.straightdope.com/t/root-beer-foam/193003/3 "2003-08-05T05:49:04Z")

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Mmmm… detergents!

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**Author:** ![caveman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/caveman/32/7242_2.png) [@caveman](https://boards.straightdope.com/u/caveman)\
**Post date:** [August 5, 2003, 6:26am UTC](https://boards.straightdope.com/t/root-beer-foam/193003/4 "2003-08-05T06:26:47Z")

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The liquid portion of Root Beer is somewhat thicker than that of other carbonated beverages, and therefore allows for more tenacious bubbles which accumulate into a large, long-lasting head that dissipates comparitively slowly. It’s the _popping_ of these bubbles that, in colas and other sodas, make them seem “fizzy” (as they explode at a high rate) while Root Beer seems "“foamy” because its bubbles grow larger and last longer.