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Why is it that after pouring a delicious beer from a bottle, I can hold it upside down for several seconds without reward, but if I wait a bit, the remainder presumably settles at the bottom and immediately pours out on demand?

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up vote 3 down vote accepted

This is very simply down to surface tension - a very small amount of beer (in a relatively thin film) will adhere strongly to a glass as the percentage of bonds between the water and the glass is high.

As the drop size increases (up to a point) more and more of the bonds are internal increasing the strength of the drop and decreasing the adhesion to the glass.

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Is it not more about foam bubbles collapsing, than small drops joining into larger ones? –  Jaime Oct 8 '12 at 17:23
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@Jaime I think we need a grant to study this one. –  Jeff Axelrod Oct 14 '12 at 17:58
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