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My wife bought me a special cup for me to drink beer out of. The problem is that, if I pour any beer in it, it goes crazy with foam. I will get just a few ounces of beer in there and the rest of the 16 ounce cup will be full of foam. The cup is hand spun from clay. The texture is still pretty rough. So, if there is any glazing, it is not really noticeable. The cup also has little brown specks in it here and there. Does anyone know the reaction that is taking place to produce all this foam? Is there a way to fix it? Let me know if I need to supply any more details. You should assume you are talking to someone whose last chemistry class was high school.

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    $\begingroup$ Yep the rough texture is a physical catalyst for the evolution of carbon dioxide from dissolved carbonic acid. Pottery glaze fixes the foaming issue. $\endgroup$ – Ben Welborn Aug 17 '16 at 21:22
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    $\begingroup$ Exactly. Chemistry has little to do with it. I mean, sure, there is a chemical reaction going on, but it is the same as in any other cup. Rough surface is the key. $\endgroup$ – Ivan Neretin Aug 17 '16 at 21:36
  • $\begingroup$ This could be a business idea. We could make a cup that is glazed except at the top. $\endgroup$ – CoffeeIsLife Aug 18 '16 at 4:25
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    $\begingroup$ I'm guessing these bumps and rough spots are nucleation sites? $\endgroup$ – Dissenter Aug 18 '16 at 7:11
  • $\begingroup$ @BenWelborn If you wish to add your comment as an answer, I can give you credit. $\endgroup$ – Joe Johnson 126 Aug 18 '16 at 13:57
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The rough texture is a physical catalyst (provides nucleation sites) for the evolution of carbon dioxide from dissolved carbonic acid. Pottery glaze fixes the foaming issue.

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