Aluminum Can - Top 4 Things You (Probably) Didn't Know About It
A soda can (also known as drink or beverage can) is a metal container designed to hold, preserve and transport a fixed amount of liquid. Most of us interact with it every day, disregarding the amount of work that goes into designing such a brilliant object.
#1 - The invention
It all started in 1795, during the French revolution, the lack of solutions to preserve and transport food weakened an already vulnerable French food supply line. Being faced with the harsh reality that soldiers were dying of malnutrition even before encountering their enemies’ weapons, Napoléon Bonaparte offered a 12,000₣ franc prize to any inventor that could come up with a cheap and effective method for preserving and transporting large amounts of food.
It took 11 years, for someone like Nicolas Appert to rise up to the challenge. Using his knowledge as a French confectioner and brewer, Nicolas found out that cooked food was able to endure inside glass jars for as long as its contents remained sealed.
And that was when an Englishman named Peter Duran, inspired by Appert’s invention, patented a similar concept using tin cans instead. Duran’s Tin cans were preferable to glass jars, as they were cheaper to produce and easier to transport.
#2 - Its evolution
By 1846, with Henry Evans’ invention of the die machine, the production of tin cans was able to increase 10 times: from 6 to 60 cans an hour. Evan’s invention was still far from the first automatic can-making machine which, in the late 19th century, would end up securing the tin can’s future as one of the main packaging and food preservation containers.
However, it was only in 1930 that the piece of technology responsible to allow the packaging of beverages in cans was invented. The interior liner, typically made out of wax or plastic, allowed for canned products’ flavors to remain intact while also avoiding them to react when in contact with their bare interior metal.
In 1935, beer was the first beverage to be sold in cans. The wide adoption across the beverage industry took its time, mainly due to the fact that the can’s interior liner was not yet perfected, causing the most acidic sodas to acquire a slightly metallic taste.
Not contributing to the can’s wide adoption was also their complex opening method. From the US flat-top cans, that required a special opener (called the churchkey), to the UK cone-topped ones, that were shaped and sealed like a bottle (i.e.: using a crown cork); the first type of pull-tab would only end up being invented in 1959.
Preceding the pull tab’s invention by a full year (in 1958), was the first-ever produced aluminum can which can probably be considered the biggest development in the can manufacturing history.
Alongside it, came Ermal Fraze’s pull tab invention. Detrimental to the can adoption across the beverage market, the pull tab allowed consumers to enjoy a drink without them having to fall back on a separate opener tool. (ring pull) By attaching an aluminum pull ring riveted lever to a pre-scored wedge-shaped tab section of the can top, the pull ring created an elongated opening that allowed the beverage to flow out while the air was allowed to flood in.
However, this ring-pull design which completely detached itself from the can was leading people to dispose of them wherever they were creating an immense amount of litter. This issue would end up being addressed in 1989 with the appearance of the ring-pull design we use today which opens the top of the can without detaching itself.
#3 - Its design
Despite having less than a tenth millimeter thick, today’s cylindrical shaped soda cans are able to hold beverages at pressures up to six atmospheres.
And the reason for them to be shaped like that is simpler than you may think... By being cylindrical shaped, cans end up combining the best of both worlds; when packed in a box they take up 90% of the available space and their rounded walls leave no weak points for carbonated beverages to apply pressure to.
#4 - Production method
Today’s aluminum cans start their life as a flat disk with a few inches in diameter.
This disk is pressed twice to form a taller cup with the same diameter as the final can; it then has its bottom pressed into a concave dome to allow it to withstand greater pressures. This whole process takes roughly a seventh of a second and it allows for a single machine to produce 600 thousand cans a day.
Finally, the outside of the can is decorated and the inside sprayed with a coating that avoids the drink to acquire any metallic taste. The still-open top can is tapered in, and once it is filled with a beverage, a separate machine immediately puts the top of the can sealing it to its body.
Conclusion
It’s hard to imagine a life without modern soda cans, so please next time you enjoy a cold drink at a sunny beach, remember the amount of precision design and manufacturing that went into it.