# Storing the kegs outside during the winter

Many of us don't have refrigerators for these 50 liter kegs and the CO2 tank. With due care not to expose the CO2 tank in direct sunlight, to what temperatures will these pressurized kegs be fine with 4% alcohol cider inside them ? How about 7% ?

• I presume you're concerned about the contents of the kegs freezing? I only ask because you mention keeping things out of direct sun (which would probably cause them to heat up). Commented Nov 11, 2018 at 14:02

## 2 Answers

I don't have all the math in front of me but a typical beer freezes in the mid 20's Fahrenheit. Lower alcohol might be 27F and higher might be 24F. There are a lot of different factors like the volume of liquid and wind and the alcohol. I would think that if you left a full keg out overnight and the temperatures dipped into the upper teens, you'd probably be ok with it not freezing completely through and busting the keg open. The larger the volume of liquid the longer the liquid will take a while to get to freezing. Long term storage outside is not recommended because of the swing in temperatures is not good for the quality. I store beer and wine outside all the time during the winter months.

Here is a good discussion about the freezing point of beer and it applies here.

There's a formula used for determining the freezing point of a given beer in the brewing industry, taken from this book:

``````Freezing point(°C) = -(0.42 * ABW% + 0.04 * OG[°P] + 0.2)
``````

You can easily convert ABV to ABW by:

``````ABW% = ABV% * 0.82
``````

Or you can get a formula for which you only need OG and FG, by:

``````ABW% = ~ 0.42 * (OG - FG[°P])
``````
• One caveat. This may tell you the freezing point of the beer, but it doesn't tell you how long a certain volume will freeze. A bottle will freeze quicker than a keg obviously... Commented Nov 13, 2018 at 20:00
• Yes, agreed. I think it's worth having as a quick and easy "do-or-don't" kind of calculation (good for setting the cooling temperature on a vessel or something like that). Obviously there are a great many ways in which we can't predict the exact behavior of unique and not-fully-characterized circumstances, though as you mention, there are many good rules of thumb. Commented Nov 14, 2018 at 0:22