|MadSci Network: Chemistry|
A very important question, and one close to my heart! Because the beer bottle (or can) contents are under pressure, the water in the beer will not freeze at a 'normal' temperature. I wish I had a more detailed diagram to reference but this phase diagram of water was the best I could find quickly. I doubt a phase diagram for a complex system like beer exists...
But, using water as an example: Before you open the bottle, the beer is under roughly 30 bar of pressure and, on a warm summer day for you, is probably -10C? I am sure I am way off the mark, but my point is that at a higher pressure, the contents are going to remain liquid at a lower temperature... until you open the bottle. Now, you have rapidly reduced the beer's pressure but your temperature hasn't changed. You have moved straight down a vertical line (of constant temperature) and your beer turns slushy.
I can't really think of a way to avoid this problem, except to warm up the beer before you open it. Somewhat counter-intuitive and probably very difficult in Antarctica... Cheers!
Moderator's note: Actually, hot beer is a common drink in Ursula Le Guin's novel, "The Left Hand of Darkness." It takes place on a world which is in the middle of an ice age, and the temperature never gets much above 55 or 60 degrees Fahrenheit, so that (as an Earthling character remarks) "hot beer is something you come to appreciate."
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