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Chemists! A question. Here Lord Brabazon is describing a thing:
There was in those days a strange form of tinned food which you cannot get now. In a balloon you naturally cannot use a flame and consequently you could have nothing hot, for it was before the day of the thermos flask. But there was some tinned stuff called "Calorit" which consisted of any food such as stew or soup or anything you liked hot, the tin being inside another cylinder. When you wanted to eat you made a hole from the outside to the inside cylinder, and I suppose water came in contact with some chemical, for if you left it for about a quarter of an hour it became so hot you could hardly eat it. It was the most remarkable of tinned foods and I could never understand why it disappeared, for it would be of inestimable value nowadays for people in motor-cars.
I can find only one other reference to Calorit, in an 1905 article on feeding soldiers. What in all likelihood was the magic ingredient that superheated? And is the reason for its disappearance, as I strongly suspect, that it was actually massively carcinogenic?

EDIT: Thank you all. I feel mildly enlightened. Glad to have been wrong about the carcinogenic thing, too.


( 10 comments — Leave a comment )
Oct. 11th, 2011 02:17 pm (UTC)
I think calcium oxide has been used in this way. It gets very hot in contact with water, and produces calcium hydroxide, which is unpleasantly alkaline if concentrated, but completely non-toxic if reasonably diluted.
Oct. 11th, 2011 02:34 pm (UTC)
Oct. 11th, 2011 02:39 pm (UTC)
I don't think it's disappeared, either. ISTR that Nestlé was using something similar for coffee-in-a-can within the last decade or so, (though I've never drunk the stuff and haven't seen it on the shelves lately)

ETA: http://www.packworld.com/print.php?id=13601

Edited at 2011-10-11 02:40 pm (UTC)
Oct. 11th, 2011 03:00 pm (UTC)
The Nestle coffee failed because it had a short shelf life, owing to the milk(sic) content, and it didn't sell well enough to support the stock turnover that could support this.

It was also a Nestle product (la lucha continua) and quite, quite disgusting.
Oct. 11th, 2011 02:40 pm (UTC)
I don't know, but <selsdon>when I was in Tokyo, there was a vending machine in my hotel selling food in plastic containers, and I can't remember exactly how it worked but opened the container, reassembled it somehow, pulled a string and a pad heated up and warmed up the contents. I think mine was spaghetti bolognaise.</selsdon>
Oct. 11th, 2011 03:04 pm (UTC)
Lots of these over the years. Most are based on calcium chemistry (quicklime et al) and require water to be added. US military ration pack heaters have this poured in from a waterbottle. Nestle coffee cans had it stored in the base of the can, via an ingenious mechanism where a flexible outer base was still strong enough to allow it to be pushed hard enough to rupture an inner base. Well-established chemistry, mundane food product engineering (I blame Thatcher, the ice-cream snatcher) but a very clever and sadly overlooked bit of mechanical packaging design.

Some heaters also work with air, not water. These have exciting chemistry and are not to be trusted.

The US rat pack heaters are supplied a few to a box and many are left spare afterwards. They're handy buys through the surplus dealers for hillwalkers etc.
Oct. 12th, 2011 06:56 am (UTC)
As I understand it, the MRE flameless heaters contain magnesium powder, salt and iron oxide powder; greater energy density than in lime slaking.
(no subject) - gummitch - Oct. 12th, 2011 07:20 am (UTC) - Expand
Oct. 12th, 2011 12:00 pm (UTC)
Argh. Sorry, braino - should have typed "iron powder", not "iron oxide powder". The energy comes from the rapid oxidation of Mg by water, giving magnesium hydroxide and hydrogen as products (the iron and salt are there to increase the rate of the reaction).

Given that the heaters give off hydrogen gas, it should come as no surprise that, if you type "mre heater" into Google, one of the suggestions you're given is "mre heater bomb".
Oct. 12th, 2011 08:01 am (UTC)
I imagine that if your warehouse was flooded, and then it subsequently burned to the ground, the conversation with the insurance people would be hilarious.
( 10 comments — Leave a comment )

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