Why do liquids appear to “boil” during vacuum packaging when they’re not actually boiling?

During the vacuum sealing process, it's common to see some liquids—like soups, sauces, or marinades—begin to bubble, giving the impression that they are "boiling." However, this phenomenon is not due to an increase in temperature, but rather to a reduction in atmospheric pressure inside the chamber.

When air is removed, the boiling point of the liquid decreases. This means the liquid can begin to bubble even at very low temperatures, without actually reaching 100°C. If this process continues, the liquid can escape from the bag and be drawn into the pump or vacuum system, causing equipment damage or contamination.

Henkovac vacuum packaging machines feature smart sensors that automatically detect this critical point, stopping the process just before the liquid begins to “boil.” In this way, they ensure a safe, clean seal with no product loss.

Practical tip: to avoid this effect, it is recommended that liquids do not exceed 14 °C before packaging. The higher the temperature, the lower the boiling point during vacuuming.

Thanks to Henkovac technology, vacuum packaging of liquids is more safe, hygienic, and efficient, maintaining the integrity of both the product and the equipment.

At Industries FAC, we are the official distributor of Henkovac in Spain. If you would like more information about their vacuum packaging solutions, please contact our team.