Twist-off caps: what they are and how to use them

06 October 2024

Fruit juices, sauces, jams—whether produced on an industrial scale or at home—twist-off caps are a key element in packaging and preserving food products. These are lightweight metal lids designed to screw on and off easily. Thanks to their spiral structure, twist-off caps create an airtight seal that preserves the freshness and integrity of the contents.
During sealing, twist-off caps generate a vacuum inside the container thanks to an internal gasket that compresses against the rim of the jar, preventing air and bacteria from entering. This feature helps maintain the flavor, aroma, and nutritional value of products, keeping them stable for long periods without the need for artificial preservatives.

Ease of use

Their practicality makes them popular in both industrial and home settings, as they allow jars to be sealed with a simple twist while keeping the contents secure and easy to reopen. However, the effectiveness of twist-off caps also depends on proper sealing, which is essential to ensure vacuum retention and safe product preservation.

Common mistakes

Several common home-use mistakes can compromise the seal. One of the most frequent is over-tightening by hand, which may deform the cap and reduce the gasket’s effectiveness. On the other hand, insufficient tightening fails to create the necessary pressure to ensure a proper seal. Another risk is reusing worn caps, which are designed for single use and lose their sealing capacity over time. Finally, sealing jars without properly cleaning the rim can leave food residues that prevent an airtight seal and compromise product safety.

Safety

In the food industry, where quality must be ensured on a large scale, precision machinery is essential. For this reason, Tenco has developed capping machines like the Easycap, a pneumatic capper suitable for various twist-off cap sizes. Easycap can seal up to 600 pieces per hour, using a pneumatic system that precisely adjusts the pressure for each jar to achieve consistent and uniform sealing. This process minimizes contamination risks and preserves product quality even during long-term storage, ensuring high safety standards.

Tenco’s commitment to businesses

Twist-off caps remain a versatile and reliable solution for food packaging, whether in small-scale artisan production or industrial packaging lines. However, ensuring product safety and quality for the end consumer requires proper sealing at every stage. With Tenco’s equipment, businesses can rely on precise and dependable solutions that preserve the freshness and integrity of their products right up to the moment of consumption.