Much more useful than political commentary -- "How to Chill a Hot Beer or Soda in 3 Minutes". Via Henley and the Agitator.
Photo by Flickr user Ckaroli used under a Creative Commons license
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Actually Useful Blogging
16 Jun 2008 09:07 am
Comments (16)
Same principle JK. This trick was used to make ice cream. If you have a "Homemade" ice cream maker, I think they still use it.
If you're in a hurry, acetone drops the temperature much faster than salt, but you can't get as cold.
I'm surprised this isn't more common knowledge. Matt, you apparently haven't done enough drinking. And you cycle to work. Shame on you.
Related trick:
If you have a hot bottle of water that has been sitting out in the sun, take a sock, soak it in water and put the bottle in the sock and the sock in the sun.
By the time the sock is dry, the water in the bottle will be cool.
This was on MythBusters about 3-4 years ago. Immensely valuable. Yes, homemade ice cream requires lots of salt. And if you have the old school style (I do), also lots of cranking. Good times.
We used this method back in high school with rock salt. One drawback we encountered was that our beer tasted very strongly of rock salt.
We were using cans rather than bottles, so I'm not sure if the salt bonded with the aluminum or what else might have gone wrong (perhaps we could have simply rinsed the tops of the cans off before drinking). But anyway, YMMV.
@JK: The presence of the salt does allow the water temperature to drop below 32 degrees, but this trick also works in part because the salt speeds up the melting of the ice. The phase transition from solid to liquid absorbs heat, which helps keep the water extra cold.
That's why calipygian's trick is related; it simply uses the transition from liquid to gas rather than from solid to liquid. Just like melting ice, evaporating water absorbs heat from its surroundings (in his example, the warm bottle).
The pic is cool -- it took me forever to realize that it was a beer bottle (and hence connected to the subject) and not, inexplicably, a jelly-fish.
Another trick (I've never tried it, just heard about it): even if the temperature is above freezing, if you leave a wide, shallow tray of water outside in dry conditions overnight, a layer of ice can form on the water. The rapid evaporation cools the water enough to get it to freeze. I think it's the same process that freezes the dew on your lawn, even when the temp never gets below 40.
According to a TA in a college course I took on India, this is a traditional way to make ice in dry, hot regions in India.
It's been too long since I've taken first year thermo, but from what I remember the "evaporative cooling to ice" trick will only work if you have enough insulation of the "system" (e.g. no wind to blow fresh, non-cooled air over the ice) and the dew point is below freezing.
You can still chill beers in about 7 minutes if you have no salt or no freezer. I used to do a lot of road trips and learned how to do it in a motel room. Just fill up a waste basket with beers, cover them with ice, and then top it off with cold water to improve thermal contact. The key is to place the beers vertically because convection is more efficient on vertical surfaces. It may not be as slick or as fast as the linked technique, but the materials required are always available at even the cheapest of motels.
Generally beer that has been allowed to heat up to 80 degrees is going to taste pretty yucky even when you cool it down.
And, calipygian, if you let a plastic bottle of water heat up in the sun you really should just dump out the water and toss the bottle into the recycling bin. The heat from the sun causes all kinds of nasty chemicals from the plastic to leach into the water. You'd be much better off drinking from the tap than trying to cool it down--though the science of your technique is pretty neat.
And, calipygian, if you let a plastic bottle of water heat up in the sun you really should just dump out the water and toss the bottle into the recycling bin. The heat from the sun causes all kinds of nasty chemicals from the plastic to leach into the water. You'd be much better off drinking from the tap than trying to cool it down--though the science of your technique is pretty neat.
The Iraqi Freedom vets I learned it from really didn't have the option of throwing out bottled water and drinking from the tap.
Enough about beer. How did CKaroli take that picture???
When I lived in Niger, people would put their drinking water in clay jugs in the dark corner of a room. It always seemed to be cooler than room temperature, but initially I didn't think this was possible. In fact, it was cooler than room temperature. The clay jar sweats, and the evaporation cools the container.
Evaporative cooling is well known. Houses in the southwest use it for cooling their houses. In Texas, they use it to cool livestock in their sheds, so you know it has to be cheap. For livestock, one side of the building has a porous material that has water running down it. The other side of the building has fans to pull air through the porous material and into the building.
Doesn't work if the air is humid; it is limited to dry places. Which is why is works well in Iraq, less well in, say, DC in the summer.
PDX reminded me of a conversation I had back when I was an agricultural economist, flying to an ag-econ convention in New Orleans, sitting next to a differently-gruntled dairy farmer returning home to Southern Mississippi. Apparently it is hard to be a dairy farmer in SoMiss because the cows get too hot and lose their appetite (milk production is a metabolic activity that throws off heat as well as cream). I noted that the dairy farmers in California's exceedingly hot Imperial Valley have misters in their barns to cool off the cows.
The farmer drawled, "well, son, here if you install misters here you'll just have a lot of wet, hot cows."
Comments closed June 30, 2008.
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Heads in the Sand
Isn't it just that the salt lowers the freezing temp of the water, and thus gets colder than otherwise possible? Same reason that they put salt on the roads in winter.
Posted by JK | June 16, 2008 9:30 AM