Freezing Point of Beer

My boss asked me the other day what the freezing point was for beer. I said well, theoreticly since most beers are on average 5% ABV then 95% of it is water and should freeze at 32F and the remaining alcohol I didn’t know because I don’t know it’s freezing point.

He said that didn’t make since because he goes to a store with a walk in cooler with a thermometer that says 25F, which has bags of ice in there that doesn’t melt, but the beer is not frozen.

Can anyone shed some light on this topic??

Originally posted by donrajin
My boss asked me the other day what the freezing point was for beer. I said well, theoreticly since most beers are on average 5% ABV then 95% of it is water and should freeze at 32F and the remaining alcohol I didn’t know because I don’t know it’s freezing point.

He said that didn’t make since because he goes to a store with a walk in cooler with a thermometer that says 25F, which has bags of ice in there that doesn’t melt, but the beer is not frozen.

Can anyone shed some light on this topic??

From an article from the University of California at Davis (referenced above by FlacoAlto)

The freezing point of a beer is given as Freezing point

°C = –0.42*ABW + 0.04*OG + 0.2

ABW is the % of alcohol by weight
OG is the original gravity of the wort

On this basis, each 1% increase in alcohol content lowers the
freezing point by 0.42°C and each increase in gravity of 1°Plato
(P) raises it by 0.04°C. Thus, no beer will freeze at –1°C, and
products at higher alcohol concentrations (including high-gravity
brews prior to dilution) will withstand even lower temperatures.

Lots of things affect the freezing point including the ABV, the dissolved sugars, and salts/inorganics. It’s freezing point is well below 32, due to the presence of all of these. It’s a misconception that freezing only removes water... you get preferential removal of water, but that’s not the only thing being removed. Some alcohol, salts and sugar will also come out as you approach the freezing point. It’s also affected by dissolved gases and nucleation sites. In short, it’s actually pretty complicated, and you’d need to dig into some physics texts to really get the answer you want.

You can dig through this reference if you really want to know more about it.

http://www.springerlink.com/content/3372177417526h51/fulltext.pdf