Just curious. I’m going camping this weekend. I’m doing a low-carb thing, so no beer-- I bought a handle of liquor (I think it’s called a ‘handle’-- it’s like the size of 2 fifths. Not that I plan to drink it all myself in one weekend; I want to have more than enough in case my friend wants some or nearby campers stop by). It’s in the freezer now.
If I froze a similar quantity of water, it would effectively keep food cold in a cooler by itself. But since 80 proof alcohol does not freeze, is it as effective as ice, as a cooling method? Or does the act of ice gradually thawing convey better and / or longer-lasting cooling properties?
Refrigerated/freezer cooled alcohol will stay colder longer than water because it evaporates more quickly than water. It’s the same reason why you will feel more comfortable on a 90 degree low humidity day than on a 90 degree humid day. Faster evaporation on the former has a cooling effect.
But the alcohol I’m storing in a bottle in my cooler is not evaporating. You’re saying the process of evaporation causes the cooling effect, of which I’m aware.
Or are you saying that just due to the nature of alcohol evaporating more quickly than water, it conveys more cooling effect than water in general? I’m not sure I understand your answer.
80 proof booze has about the same specific heat as ice, so it’ll absorb the same amount of energy warming up as ice would.
But… the booze won’t undergo a phase change (i.e. melting), which takes a fair amount of heat to accomplish.
So overall, if you’ve got the same mass of ice and booze, the ice will take more heat to bring up to temp and melt, and once it’s melted and 0C water, it takes quite a bit more energy to bring that 0C water up to 1C than to bring the booze from 0 to 1C, as the specific heat of water is considerably higher than that of 80 proof booze.
The good news is that according to Google’s AI, the mass of a given volume of ice and of 80 proof booze is about the same, so there aren’t really any strange goings on with the density of ice vs. booze, etc…
Won’t the effect of the specific heat of fusion of water (i.e. cost of melting) dwarf any differences in regular specific heat between the substances, for the heat range being discussed?
In a word - yes.
Latent heat of fusion for water is 334 kJ/kg. Specific heat of liquid water is 4.2kJ/kg.
Water would need to rise 80 C to match the energy gap across simply melting.
ETA - specific heat of ethanol is 2.7 kJ/kg. So 127 C rise in temperature for the same mass of water melting.
I appreciate the detailed answers, and I’m glad the post is sparking a bit of discussion, but as someone who got a D in high school Physics (I like to think more due to Senioritis than stupidity, but still ) can you also provide a “in conclusion, I maintain that 80 proof alcohol chilled to 0F as compared to the same quantity of ice is [better / worse / equivalent] in its cooling properties”? Thanks.
Water ice is vastly, vastly better at cooling than even pure alcohol chilled to the same below-freezing temperature.
Once the ice has entirely melted to water, alcohol at that same above-freezing temperature will cool the other stuff more quickly, but less effectively over time.
I keep 80 proof vodka, tequila, light rum, and dark rum in my freezer at 14F/-10C. Also 94 proof gin. The bottles are all unsealed and at various levels of emptiness. They get slowly used up and replaced periodically; they aren’t monuments to parties long forgotten.
If any of those boozes have developed ice, it’s microscopic crystals only. Which is generally not how ice behaves in solution; it tends to grow clumps.
When poured out, the liquor is definitely more viscous than it is at room temp; not quite as viscous as most liqueurs (e.g. cognac), but clearly thicker than their room temp norm.
I’ve seen a little slush form in a bottle. Not even that cold, but sitting undisturbed on it’s side for a long time. It was my vodka, but not my freezer and a lot of it was gone since I left it there. Perhaps contaminated by something else. Didn’t occur to me before now but who ever was drinking it may have added water to hide the pilfering.
Just for extra clarity, water ice is very good at keeping things cold not only because the ice itself is cold, but because it takes a lot of energy to melt the ice (the latent heat of fusion). Since the alcoholic beverage isn’t frozen, it lacks that property and would be much less effective than ice even if it was at the same temperature and had the same specific heat.
Water is quite miscible (creates a homogeneous mixture) in alcohol, and with an 80 proof (40%) or higher ethanol liquor will create a fine slurry of water ice crystals suspended in the alcohol. You can get the water ice to clump together by centrifuging the liquid and using the difference in specific gravity to separate them or aerate the solution to carry the lighter alcohol to the top but at temperatures of 0 °F (-17.8 °C) you don’t get a lot of natural convection that would separate the mixture.
The thermofluid properties of liquor have already been addressed but I’ll just note that in terms of specific heat capacity water is the best commonly available substance, and its unique properties of slight polarity, high latent heat of fusion and enthalpy of evaporation, and becoming less dense at standard atmospheric pressures just before freezing (around 4 °C, which is why water floats) result in some very unique thermodynamic and phase behaviors why is why the presence of water in the liquid state is one of the hallmarks which planetologist look for in potential habitats for extraterrestrial life.
I have a “mercury” thermometer that lives in a freezer door compartment. I wasn’t smart enough to check before I took all the booze out, and that process left the thermometer out in the air awhile before I took my reading.
Now, ~1h later with the door closed the whole time I went in there and grabbed the thermometer & read it immediately.
As you suggested, it’s saying 0F / -18C. And that’s in the door. Might be a little colder yet in the very back
) can you also provide a “in conclusion, I maintain that 80 proof alcohol chilled to 0F as compared to the same quantity of ice is [better / worse / equivalent] in its cooling properties”? Thanks.
