# caffeine

**URL:** <https://boards.straightdope.com/t/caffeine/104389>\
**Category:** Factual Questions\
**Created:** [April 18, 2002, 9:06pm UTC](https://boards.straightdope.com/t/caffeine/104389 "2002-04-18T21:06:31Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Palo\_Verde](https://avatars.discourse-cdn.com/v4/letter/p/65b543/32.png) [@Palo\_Verde](https://boards.straightdope.com/u/Palo_Verde)\
**Post date:** [April 18, 2002, 9:06pm UTC](https://boards.straightdope.com/t/caffeine/104389/1 "2002-04-18T21:06:31Z")

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How much caffeine is there in decafinated coffee?

I assumed there was none but my husband claims there is some, although he is not sure how much.

Is it just a tiny bit?

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**Author:** ![Dilbert](https://avatars.discourse-cdn.com/v4/letter/d/58f4c7/32.png) [@Dilbert](https://boards.straightdope.com/u/Dilbert)\
**Post date:** [April 18, 2002, 9:26pm UTC](https://boards.straightdope.com/t/caffeine/104389/2 "2002-04-18T21:26:40Z")

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5-10 milligrams in general, compared to around 200 in a normal cup

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**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\
**Post date:** [April 18, 2002, 10:15pm UTC](https://boards.straightdope.com/t/caffeine/104389/3 "2002-04-18T22:15:06Z")

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Caffiene, AFAIK, is usually removed by submitting the coffee beans to carbon dioxide at its triple point, in which caffiene is highly soluble. This means that caffeine leaves through a diffusion process and so some must always be left over.

I’m not aware of any other methods for decaffeination.