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Standard clear PET cans offer incredible versatility for various packaging needs. They are perfect for cold brew coffee, craft beer, sparkling sodas, and chilled juices. However, there is one specific application where standard PET cans are not suitable: Hot Filling.
If you are producing pasteurized juices, teas, or syrups that need to be bottled at high temperatures (typically above 85°C / 185°F), standard PET cans are not the right choice. Here is the science behind why.
The primary reason lies in the chemical structure of Polyethylene Terephthalate (PET). Every plastic has a "Glass Transition Temperature" (Tg). This is the point where the polymer chains begin to move freely, transitioning the material from a rigid, glass-like state to a soft, rubbery state.
For standard PET, this transition temperature is approximately 65°C to 70°C (149°F - 158°F).
Most hot-fill processes require liquid temperatures between 85°C and 92°C. If you pour liquid this hot into a standard PET can, two major failures occur:
1. Immediate Deformation: The heat exceeds the Tg of the plastic. The can will immediately lose its structural integrity, shrinking and warping into an unrecognizable shape.
2. Vacuum Collapse: As the hot liquid cools down inside the sealed can, the liquid volume shrinks. This creates an internal vacuum. Without special vacuum-absorbing panels, the PET can will be crushed inward by atmospheric pressure.
Standard PET cans are specifically designed for Cold Fill or Ambient Fill (room temperature) processes (below 60°C). This makes them ideal for:
If your production line relies strictly on hot filling for sterilization, you would typically need alternative packaging options:
To ensure your product looks premium and professional, always fill standard PET cans at temperatures below 60°C (140°F). By sticking to cold or ambient filling, you preserve the crystal-clear transparency and perfect cylindrical shape that makes your product stand out on the shelf.
