When does beer freeze?

AT what temp will my beer freeze?

Ive just started lagering my Oktoberfest and my lagering chamber doubles as my kegerator.

My carboy sits on the hump in the kegerator which is about 5ish degrees warmer than the very bottom of the kegerator and I don't want to freeze the beer in my kegs...

How low can I/should I go?

 

Water freezes at 32°F. Beer's freezing point shouldn't be much lower than that due to the (relatively) low alcohol content. To be safe, call it 32°F.

 

My keezer used to be set at 30*F I had a 4.3% wheat that had a little ice in it but my 5.8% pale ale, and 7.3% IPA did not. I now set it at 34*F.

 

Yea...I typically keep the temp at 36-38 but since I'm lagering I was trying to get it down to as close to freezing as possible

 

Try putting a small fan in the bottom of the freezer, won't take much electricity to run. Will keep the whole freezer the same temp.

 

What kind of fan?

 

The water in the beer freezes at the temp that all water freezes at... 32F. The water will freeze and the sugars/alcohol will not because pure ethanol alcohol freezes at -114.3 degrees Celsius. This is how we make eisen beer/wine aka freeze concentrated beer/wine.

Any fan that you can get in the freezer should work. Most people use computer fans.

 

Not quite. The initial freezing point of 5% abv beer is going to be about 29º F, What happens after that is really interesting. As the beer cools the water freezes a little bit at a time. The ice crystals fall out of solution, leaving a slightly stronger beer with a slightly lower freezing point. The freezing point is on a curve all the way down to freezing point of pure alcohol -173.2º F.

More information:
http://en.wikipedia.org/wiki/Freezing-point_depression