Joshua Shriver <jshriver <at> gmail.com> writes:

> How does this work?

Put the beer in the deep freezer, wrapped in something soft (like a *dry*
kitchen rag). Avoid vibration and moving the bottle at all while it freezes. The
beer will be supercooled but liquid. Take out the bottle, remove the wrap (all
without shaking it) and then do as the movie shows. Ymmv, and the bottle may
freeze and crack making a mess. It may also freeze and crack while it's in your
hand. Use a kitchen mitt and safety glasses and keep it away from you while
handling it.

The physics involve internal cohesion forces in an undisturbed liquid and the
lack of nucleation points. When something is cooled it will not start freezing
solid until a 'starting point' exists. Then freezing occurs starting from it.
Cold filtered beer is particularly void of any inclusions that could serve as
nucleation points, so it stays liquid. When the bottle is bumped hard some of
the CO2 is vented as tiny bubbles and these (and the beer that is now CO2-less
where the bubble formed) start the crystal formation.

Peter P.


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