The Manufacturing Reason Canned Foods Are Ribbed

Ever wondered why most canned foods come with ribbed walls? It all has to do with the industrial canning process: Canned products are processed at incredible temperatures and vacuum pressures to kill all microorganisms for long-term, preservative-free shelf stability. Of course, the cans themselves have to be reinforced to withstand it all without compromising the airtight seal. 

The "ribbing" on a can — more generally known as corrugation — helps strengthen the can and prevent cracks while being processed. First and foremost, the ridges add room for the can to expand when heated and compress when pressurized, working on the same logic as the main part of an accordion or the joint of a bendable straw. 

However, the corrugation adds as much structural integrity as it does flexibility, which is essential for properly preserving the food inside. The repeated triangular geometry introduces points of rigidity all across the metal, reinforcing against denting and bending that could compromise the seal of the can. Effectively, the ribbing of a can adds the sturdiness of thicker metal walls without the added weight.

The dangers of a compromised can

It's not just the manufacturing process that cans are reinforced for — corrugated walls also help protect against the natural stresses of transportation and storage, especially when it comes to heavier products. Rattling and crashing into each other while being shipped over long distances can cause any number of cracks in weaker cans, and even the smallest of hairline fractures can severely compromise the freshness and quality of canned food.

Per the CDC, the low-oxygen environment inside of a can is the perfect ground for bacteria to develop and release deadly botulism toxins — which is why it can be so dangerous to make canned food at home and why you need to carefully dispose of compromised cans. All it takes is a microscopic breach caused by a small dent for bacteria to sneak into the can and put any potential consumers at risk of muscle paralysis, breathing difficulties, and in severe cases, death.

That's not to say you should stop buying canned foods. Cases of foodborne botulism from commercially canned products are rare, in no small part because of the flexibility and structural integrity added by corrugated metal cans. However, it's worth checking for small signs of damage the next time you're purchasing canned products with low acidity and high botulism risks, such as asparagus, green beans, beets, corn, potatoes, and nearly every variety of meat or dairy products.