June 26, 2025, 12:25 pm | Read time: 3 minutes
Cans come in all shapes, usually round and often smooth, such as those for beverages. Sometimes they have ridges on the side, especially when containing food. But why do some cans have ridges and others don’t? For this article, myHOMEBOOK went on a quest to find out.
Cans are very practical. They can be stacked, making them ideal for storing food, especially fruits, vegetables, or soups that need to last a long time. Often, the can emerges when the fridge offers nothing fresh. Many cans immediately reveal their side grooves beneath the paper label. There are several reasons for this, as the cans must withstand quite a bit. An expert explains what it’s all about.
The Function of Grooves in Cans
“The grooves are called beads in technical terms,” explains Sibylle Vollmer from the Association of Metal Packaging (VMV) in Düsseldorf when asked by myHOMEBOOK. “The beads provide stability to the can.”
In general, a can withstands quite a bit. Clever people once discovered that a can must withstand up to 200 kilograms without deforming. This much weight can accumulate when several cans are stacked, such as for transport on a pallet or in large supermarket shelves.
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Cans Must Endure a Lot
But the beads are less about weight, explains Sybille Vollmer. “The food in the cans should be preserved for as long as possible. Therefore, the filled and sealed cans are heated to over 100 degrees to sterilize the contents.”
Through heating and subsequent cooling, the can deforms. The metal initially expands with heat. When the can cools, the material contracts again. It’s all a matter of physics. If the surface were smooth, the can would deform and, in extreme cases, burst. Hence the beads on the side.
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How Are the Beads Formed in the Material?
Most cans are made of tinplate. This is usually rolled in a smooth form onto large coils. These tinplate coils, also called coils, go to the can manufacturers.
Here, special machines shape the can. First, the sheet is punched accordingly. The punched part becomes the can body. This is welded together at the longitudinal edge. During this process, the beads are also formed in the sheet, turning it into a food can.
And why must the can be round? Of course, there are also square cans, for example, for breakfast sandwiches or freshly chopped vegetables. However, square cans are impractical for preserving food. Here, too, physical laws apply: Round materials expand evenly in all directions when heated, like a balloon. Cans with corners would burst due to the heat pressure.