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High-speed cooling for the kitchen with flexible brine packs


Everybody who has used a microwave oven has wished at times for a "microwave fridge" that could cool things quickly. Of course the process is very different.

The fastest way to cool things, however, is to get lots of surface contact with a very cold fluid that will absorb and coduct lots of heat. And indeed, drop a drink can into ice-water, which is of course at 0 degrees centigrade (32F) and it will cool reasonably quickly.

Far faster is to drop it into icy brine water. Saltwater (brine) freezes much coooler. A 23% (by mass) brine doesn't freeze until -21C or -6 degrees farenheit. (In fact, 0 on that scale was in part derived from the freezing point of common brine, I believe.) A cooler full of salty icewater will cool drink cans much faster -- just a minute in fact, and this is well known. But it gets salt water on things, and can't be used to cool non-sealed things.

I propose packages of 23% brine in extremely soft and flexible (even at freezer temperatures) plastic packs. Perhaps moderate amounts of 1" or 2" spheres, not tautly inflated, so they can be squished and will conform to objects. The covering must be as conductive as you can reasonably get it, while staying flexible and not too fragile. Ideally dishwasher safe too...

Put them in the freezer, and then when you want to cool just about anything, pack them around it in a box. Get lots of surface area contact. Most freezers are supposed to be kept below 0F (-18C). They could even be placed on top of messy foods, if the container is easy to clean, and as noted, possibly could be dishwashable with modern ingredients. If you just slot a drink can or bottle into them, you would not need to clean them.

There are some risks. These packs could actually frostburn skin fairly quickly, I think. Small plastic pick-up handles/tabs would make sense for moving them by hand, or gloves or tongs could be used. Of course brine is not going to be toxic so puncture would generate nothing worse than a salty mess.

Brine is used in ice-cream making and other cooling applications already. For maximum cooling, a simple device with cold 23% brine, a conductive surface and some means to circulate the brine to generate convection would be in order.

There are some salts, such as Magnesium Chloride and Ca2Cl which stay liquid at much cooler temperatures. Those could be used in a tiny mini-cooler which takes them down to seriously cold temperatures. Then items to be flash-cooled could be inserted among the chilly pillows. Of course, expect frozen condensate if there is water around.

You can test this plan out yourself with solid zipper freezer bags. Take 750ml water and about 230g NaCl salt to make your brine. You don't have to get it exactly right, your freezer is probably not at -6F.


Not wanting to talk off topic, but I happened on your site and recall reading about the work you did on the Commodore 64. That was 25,000,000 years ago. Strange how a name you read some years later can trigger memories.

We often have big pots of stock, soup or stew that we want to cool. We started by using a small fan aimed at the pot, and it really does make a difference in cooling time. We estimated it at a factor of two or better.

1) When the fan died, we started using the smaller of our kitchen sinks. We'd stop the drain, fill it with water, put in the pot and two or three of those freezer packs they use for shipping food overnight. The cooling is up by a factor of four. We can cool a six quart stock pot of boiling hot liquid to lukewarm, i.e. refrigerator ready, in about 15-20 minutes. As expected, cooling is quicker if you slosh the water now and then.

Obviously, we need an underwater fan to make this really work.

2) There is a gadget we first saw in a winestore in Leura, NSW, Australia, but we have since seen elsewhere. It is a wine chiller that works using some kind of refrigerating medium. Basically, you put the wine (or smaller champagne) bottle into a plastic sleeve that sticks down into the refrigerant. The thing revs up and sloshs around, rotating the bottle, at least in some models. In a few minutes, your wine is icy.

I'm not sure if this is available for home use, but their is a simpler concoction on sale at Amazon (, the Vacu Vin Guy Buffet Wine Rapid Ice Wine Chiller. This looks like a plastic sleeve containing refrigerant pack filler that can be chilled in the freezer, then slipped around a bottle of wine to cool it rapidly.

>You don't have to get it exactly right, your freezer is probably not at -6F.

This is the one nice thing about living in a place where the winters can get nice and chilly: in addition to never running out of freezer space (I finally had to throw away some frozen orange juice when I forgot it outside and it thawed out in the spring), you can cool things down extremely quickly. Toss a can of room-temperature soda into a -20F snowbank (this is key, as the snow conducts heat away from the can faster than air if you just set it on the porch) and you have a perfectly chilled drink in just a few minutes.

Of course, the *downsides* to living in a place with chilly winters are myriad--frozen skin when you sit down in your car after work, having to spend 10 minutes getting bundled up to run outside and get the mail, shoveling snow--enough to make me consider every January moving back to California...

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