Hi There !

1.  Which bottle of beer will freeze faster in the freezer?  An opened
(full) beer or a still-capped (full) beer?

2.  When I place a 12-pack of Heineken in the freezer, some of the bottles
freeze solid and some remain a liquid.  Why?  (Note:  there is no pattern. 
That is to say, the beers closest to the freezer floor and freezer
door freeze as randomly as the rest.)

3.  A beer which is still fully liquid when I pop the cap will
suddenly become slush and ice once the cap is gone.  Why?  (Note:  I
assume this has to do with pressure, but I am not sure.)

A 5-star answer will be 1-2 sentences for each of these questions.  No
supporting documentation or web sites needed.

All comments greatly appreciated, especially those from Germans,
Australians, Mormons, and anyone from Milwaukee.

Thanks. 
ron

Hello nronronronro, being a beer drinker myself and having wondered
about the same thing I couldn't resist looking for the answer to our
question. I will answer each question based on what I learned from
this web page: http://www.newscientist.com/lastword/article.jsp?id=lw115

1. The opened beer will freeze first mainly because it is at
atmospheric pressure. Also, it will have been exposed to sources of
contamination allowing ice crystals to nucleate.

2. I would guess that the pressure varies quite a bit between each
bottle and the ones with lower pressures will freeze first. I have
noticed that some beers seem to release more pressure than others when
you open them (extensive testing over many years). Also, there could
be tiny particles present in one beer and not in another.

3. This is the easiest question and it is answered very nicely on the
referenced web page. Here is the answer given:

First, bubbles of vapour released from solution will act as nuclei for
ice crystal growth in a supercooled solution. This is probably the
major process at work.

Second, increased pressure lowers the freezing point of water. This is
the basis of such commonplace things as why snowballs stick together,
why skates glide, and so on. Therefore, lowering the pressure by
opening the bottle will let water freeze at a higher temperature.

Third, the gas leaving the beer will expand, so its adiabatic cooling
will lower the temperature of the beer.

I recommend that you read the entire article. It is very interesting.

Thanks for making me find the answer to a question that has bugged me for years.

Redhoss

Redhoss,

Fantastic answer!  Your expertise is clear,
and your "extensive testing over many years" 
is reason for cheer.

Cheers!
ron

You might enjoy the alcohol trivia found on the "Fun Facts" about
alcohol and drinking page at www.alcoholinformation.org/.