Back during World War II Heinz made these tins that would heat up in minutes to provide the soldier with a nice hot can of cocoa or soup. You could just pop open the top hatch, ignite the smokeless fuel that was ignited with a fuse. Within 4 minutes, the tin and its contents were piping hot and could be poured out. Anyone could have a hot meal without cooking apparatus.
Heinz was founded by Henry J. Heinz in 1869. Heinz manufactures thousands of food products in plants on six continents and markets these products in more than 200 countries and territories. The Heated WWII cans came in:
- oxtail soup
- cream of chicken
- cream of celery
- cream of green pea
- mock turtle
- malt milk
- cocoa milk.
The fuse element, lit at the top, ran through the center of the can and would heat the contents in about 4 minutes. There were instructions to light the fuse (they often used a cigarette) and to puncture two holes, one on each side of the top to safely release the steam. If these holes were not made, or in the wrong place, injuries could and did, occur. The British Army included the Heinz self-heating cans in the troop’s ration packs for the D-Day invasion in 1944. Heinz was not the first to have heated cans. They were invented by Russian engineer Fedorov in 1897. These tins were made in small quantities for the Russian army. In 1907 there was a patent for a self-heating tin invented by the Aetna Self-Heating Company. They said that they were generating the heat by exothermic reactions, e.g. heat released by the contact of calcium oxide (quicklime) with water. It seems that all you had to do was add water to the tin starting this reaction.
Hundreds of soldiers were packed into the Liberty Ships like sardines. There was scarcely room to sleep, sanitary arrangements were primitive and there was little in the way of food. At one stage we were issued with army biscuits and cans of self-heating soup. One lighted a touch paper in the top of the can and after a while a hot can of soup was produced, at least that was the theory. From time to time unfortunately, we had cans which exploded, showering hot soup on anyone within range.Veteran – Ray Eaglan
INSTRUCTIONS FOR USE
SHAKE CAN. PIERCE TWO HOLES IN THE LID ABOVE THE ARROWS
LEVER OFF CENTRE CAP. LIGHT WICK. WAIT FIVE MINUTES.
CONTENTS THEN HOT.
ALWAYS PIERCE CAN BEFORE LIGHTING WICK
Self-heating and self-cooling cans are still being made today. These cans have double chambers, with the outer chamber surrounding the inner one. The chamber which is on the inner side of the can holds the beverage or food and the outer chamber packs chemicals that, when combined, undergo exothermic reaction.
As soon as the user wants to warm the drink or food inside the can, a ring is pulled on the can which causes a break in the barrier, separating the chemicals contained in the outer chamber. The drink or food becomes hot as soon as the reaction causes heat, which in turn, is absorbed by the contents. HeatGenie makes drinks that can be heated in 2 minutes by simply causing an exothermic reaction that the user initiates by pressing on the bottom of the can.
When the user pushes on the bottom of the can, a rod pierces the membrane, allowing the water and heating agent to mix. The resulting reaction releases heat and thus warms the beverage surrounding it. The heating agent and responsible reaction vary from product to product. Calcium oxide is used in the following reaction:
CaO(s)+ H2O(l) → Ca(OH)2(s)