Did you know that tin cans have now been used to store and preserve foods for 200 years? It’s the application of science at its best, I would say.
It seems that the first cans (short for tinplated canisters) were manufactured in Bermondsey, south London, in May 1813. The manufacturing process then required sheets of tin plate being transformed by hand into cans, with the edges and lids connected and sealed with lead solder.
The cans, which could weigh anything between 4lbs and 20lbs (1.8kg and 9kg), were initially used to supply meat to the British navy. Soon they were used to export beef, mutton, carrots, parsnips and soup to all corners of the British Empire.
According to an excellent article on the BBC website, Sir Joseph Banks, on behalf of the Royal Society, described the new invention as ‘one of the most important discoveries of the age we live in’.
Nowadays, the manufacturing process is mechanised, automated and much safer. Individual manufacturing companies produce millions of cans a day and billions per year. Cans go through a detailed cleaning and quality assurance process and are individually tested for quality. In addition, a fine internal coat is sprayed inside cans to protect the can and the food it contains.
Cans are then delivered to manufacturers where products are cooked inside the cans to avoid the need for preservation of the food.
While this process makes the contents safe to eat, our advice is that cans, once opened, should not be used to store food. This is because when a can is open to the air, the tin on the inside may transfer more quickly to the can's contents, particularly in the case of acidic foods such as fruits or baked beans. This advice doesn't apply to foods sold in cans with re-sealable lids, such as golden syrup and cocoa.
The BBC story claims that five and a half billion food cans are sold in the UK each year and that about 680 food cans pass through every UK household per year. This demonstrates a massive vote of confidence in what was once an innovative scientific breakthrough.
Are there any other food-related scientific innovations that can match the can in terms of acceptability?