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Question for a physics type

So I put some cans of beer in the freezer to chill. The time got by me and when I cracked a can, the beer (liquid) turned to ice when I poured it into the glass. Why? Just want to know. Thanks in advance.

Was your glass chilled in the freezer also? Maybe it was slushy, and so looked “liquid”

quick google search brings up some possibilities.

CO2 escaping raises the freezing temp of the solution (beer). This it is liquid until you pop the top.

I think it has to do with the properties of supercooled liquids/water but someone with a chemistry background can probably explane it better. Anyway, supercooled liquids are liquids cooled to below their freezing point and yet still remaining liquid. I think the alchohol in the beer and the pressure it is under due to being carb’d allows it to be cooled to below freezing without forming ice. Then, when opened it I think two things (maybe more) come into play. The pressure changes when the bottle is open and it is “disturbed” when poured in a glass and the result is immediatley forming ice similar. Other examples of supercooled water turning to ice inclusd a plane flying thru a cloud and forming ice immediately on the wings or freezing rain forming ice upon contact with a surface.


This would be caused by the pressure inside the can. Liquids under pressure have a lower freezing temperature then the same liquid at atmospheric pressure.

When you open a extremely cold can of beer you instantly release the presure and raise the freezing point of the beer by around 10F in this situation. This causes the beer to almost instantly become a frozen slush upon opening.

Chemist here, Pressure drop upon opening is the culprit here. I have had entire bottles freeze before I could get them poured. My fridge is right at that almost too cold point and every now and then a beer stays at the back for too long and gets a little colder than the rest. If I pour fast I can get a beer with a inch of slush on top. If I dont hurry I end up with a unprourable beer. It is very neat to actually watch what happens with a flashlight behind the bottle so you can see the crystals growing.


Mythbusters covered this too actually and it can even happen without opening the beer.

As stated above this is an example of a colligative property of beer. At elevated pressures, you decrease the freezing point AND you elevate the boiling point. Regarding the latter, that is what a pressure cooker does. By creating a closed system, you increase the pressure inside the pressure cooker and you are now cooking (boiling) at a pressure higher than 212oF (100oC).

So, as I have seen many times while ice fishing, you open a beer or a soda and it immediately freezes since the freezing point of the solution, that is now approaching atmospheric pressure, increases to a temperature that is above the temperature outside the bottle/can.

Thanks to all of the replies and responders!

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