Chill Beer to 22F Without Freezing: Physics Explained

[hulkster69]

I'm not a physics guy. I'm not even sure that that this is the right forum, but "solid state" sounded appropriate. Here is a link to a beer refrigerator that will chill beer to 22 F without freezing. http://biz.yahoo.com/prnews/061107/cgtu049.html?.v=73

My question is how this is possible? This has been driving me absolutely insane for a few days. If anyone has any ideas, please let me know.

 

[dimensionless]

Alcohol freezes at -173 °F (-114 °C). If one stirs the cold beer they might be able to prevent the water and alcohol from separating, and there by lower its freezing point.

 

[NateTG]

What's the freezing point of water?
What about water with salt in it?

 

[ChemGuy]

This is more a chemistry question! Pure substances have a freezing point. For water it is 32 F and alcohol is -173 F. If two pure materials are mixed the freexing point is "depressed" (i.e. Freezing Point Depression). It is not a straight average based upon the percentages because there are molecular forces at work. It is based on the fact that the alcohol would interfere with the ability of the water molecule to be positioned in the correct orientation for the crystal structure of the solid. This is why you never add antifreeze to a radiator straight but dilute it. Freezing point depression.

There is also a phenomenon called supersaturation. This is where a solution is actually cooled down below the freezing point. Theoretically it should freeze but it doesn't. Again this has to do with molecules arranging the correct crystal structure. There are many times that I have seen a cold bottle of wine be a liquid until it is opened but as soon as it is opened the whole thing will turn solid. Supersaturation is at work. As soon as enough energy is added (shaking or particles of dust) the chain reaction of molecules rearraing takes over.

The claim of 22 degrees is probably true but it may be difficult to dring something that cold because you would get brain freeze!

 

[Rach3]

My physics professor gave a (possibly apocryphal) story about this. With vodka, the ethanol content depresses the freezing point well into the subzero; supposedly, there are very rare cases in rural Russia where a drinker would chill vodka outside in winter, in -40 air, and forget to let it warm up before drinking. The liquid at this temperature will cause very severe burns, and sometimes death.

A somewhat related injury, except with LN2, is described here:
http://www.wpi.edu/News/Releases/19989/nitro.html

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[ChemGuy]

That is hilarious. As a chemist I have done this trick a million times...sort of. What you do is dip something in the nitrogen and freeze it solid then shatter it. Then you pour liquid nitrogen in you open hand in a manner that let's it run off your hand. No problems. Everyone is impressed. You never, never try to cup your hand. It will freeze instantly. Those physics guys! I can't believe they pour it in their mouths! Stupid even you don't swallow it!