# What % alcohol needed to prevent freezing? **URL:** \ **Category:** Factual Questions\ **Created:** [May 11, 2003, 4:13am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446 "2003-05-11T04:13:12Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [May 11, 2003, 4:13am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/1 "2003-05-11T04:13:12Z")
A 5% alcohol can of beer placed in the freezer will freeze hard as a rock. A glass of straight 90 proof whiskey will not. Right now I have a small (187ml) bottle of wine in the freezer. It’s been in there for quite a while and has not frozen. Will it? What percentage of alcohol is needed before freezing is prevented? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [May 11, 2003, 4:22am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/2 "2003-05-11T04:22:42Z")
It depends on the temperature of your freezer. Pure ethanol will freeze at -114.1 degrees C. But your freezer is probably warmer than that. ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [May 11, 2003, 4:34am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/3 "2003-05-11T04:34:28Z")
[QUOTE] \*Originally posted by Q.E.D. \* \*\*It depends on the temperature of your freezer. :smack: Doh! I didn’t even think about that! Let’s assume my freezer is running at the average tempature that most freezers run at. But… The content of water must affect this factor. For instance, I’ve now had a 14% alcohol bottle of wine in the freezer for over 2 now and it is not frozen. About 80+% is water in that bottle, yet it isn’t frozen. What ratio of alcohol to water must there be to prevent freezing, when the tempature is below that which water freezes at, yet above that which pure alcohol freezes at? ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [May 11, 2003, 4:56am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/4 "2003-05-11T04:56:41Z")
Freezer temperature, for pharmaceuticals, is defined as -20˚C (-4˚F) – definitely warmer than -114˚C. ---
**Author:** ![Rabid\_Squirrel](https://avatars.discourse-cdn.com/v4/letter/r/e0b2c6/32.png) [@Rabid\_Squirrel](https://boards.straightdope.com/u/Rabid_Squirrel)\ **Post date:** [May 11, 2003, 5:43am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/5 "2003-05-11T05:43:07Z")
OK, I’ve digged out my copy of Perry’s Chemical Engineering Handbook, and if I’m reading this graph right, a mixture of 30% ethanol by weight (60% proof) should freeze at -20°C. Your 90 proof spirits (45% by weight) woudl freeze at about -30°C. ---
**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\ **Post date:** [May 12, 2003, 4:15pm UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/6 "2003-05-12T16:15:25Z")
Well, now I’M curious and I’m not so sharp as these fellas… I have no clue what my freezer is running at, but we’ve never changed any settings if that helps. I know quantity affects the answer but if the proportion were the same than quantity is negated. That said, what is the smallest amount of alcohol per water ratio that would keep “the beverage” from freezing? I"m quite sure my freezer is not at any negative Fahrenheit numbers, so let’s be more realistic shall we? Is it 20% alcohol? Also, if someone could clarify proof versus alcohol percentage(why have it; what’s the relation?) it would be helpful. Thanks ---
**Author:** ![USCDiver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/uscdiver/32/354_2.png) [@USCDiver](https://boards.straightdope.com/u/USCDiver)\ **Post date:** [May 12, 2003, 5:00pm UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/7 "2003-05-12T17:00:14Z")
Proof = 2\*percentage. Why? Do a search, I think it’s there somewhere. Anecdotally, I’ve seen a beer freeze and explode in a freezer. So let’s say that it has to be above, say, 4%. ---
**Author:** ![stypticus](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@stypticus](https://boards.straightdope.com/u/stypticus)\ **Post date:** [May 12, 2003, 11:17pm UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/8 "2003-05-12T23:17:08Z")
Greater than the legal limit. You’re better buying a warm coat. ---
**Author:** ![JimOfAllTrades](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@JimOfAllTrades](https://boards.straightdope.com/u/JimOfAllTrades)\ **Post date:** [May 12, 2003, 11:25pm UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/9 "2003-05-12T23:25:30Z")
I’m not positive, but I seem to recall that home freezers run at about 20 degrees F, while commercial freezers run at near 0 degrees F. Does that help to check the concentrations required to get down into anti-freeze territory? ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 13, 2003, 12:28am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/10 "2003-05-13T00:28:34Z")
The term you want to search for is “freezing point depression”. Note that unlike pure water, solutions do not freeze at a given temperature but gradually over a range. At the top of the range crystals appear and constinue to form as temperature decreases until you have a solid. Between the two you have a slush of solid crystals and liquid. Only if the solution is eutectic will it freeze at one single temperature. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 13, 2003, 12:29am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/11 "2003-05-13T00:29:38Z")
> [@](#): > > \*Originally posted by RJKUgly \* > \*\*I’m not positive, but I seem to recall that home freezers run at about 20 degrees F, while commercial freezers run at near 0 degrees F. > > Does that help to check the concentrations required to get down into anti-freeze territory? \*\* 20F is hardly a freezer. 0F is more like it. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [May 13, 2003, 12:33am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/12 "2003-05-13T00:33:32Z")
Our new manual fridge at home recommends the freezer at 0F and the Fridge at 37F. ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [May 13, 2003, 3:52am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/13 "2003-05-13T03:52:45Z")
> [@](#): > > \*Originally posted by sailor \* > \*\*The term you want to search for is “freezing point depression”. \*\* That sounds about what I’m looking for. So **Sailor** , what is the term for a question that makes the questioner sure he actually asked a question that will illicit an answer that is somewhat over his head?😛 ---
**Author:** ![Largo62](https://avatars.discourse-cdn.com/v4/letter/l/45deac/32.png) [@Largo62](https://boards.straightdope.com/u/Largo62)\ **Post date:** [May 13, 2003, 4:40am UTC](https://boards.straightdope.com/t/what-alcohol-needed-to-prevent-freezing/174446/14 "2003-05-13T04:40:40Z")
I have observed that 100 proof _Stoli_ in my freezer doesn’t become solid, but turns into a clear syrup which, when poured into a chilled cordial glass is quite refreshing… in a violent sort of way. 😉