As temperatures drop, many people turn to thermos bottles to brew herbal or health drinks. But experts are warning that improper use can turn these seemingly harmless beverages into dangerous “time bombs.”
In China, incidents have been reported where thermos bottles containing drinks like goji berry and red date tea have exploded due to fermentation, causing serious injuries. In one shocking case, a woman suffered severe eye injuries when her thermos bottle suddenly exploded. The cup was later found tipped over on the table, with goji berries scattered inside — the cause of the pressure buildup that led to the blast.
Chemistry teacher Li Hua explained: “These drinks often contain sugars that can ferment, producing carbon dioxide. If the pressure inside the thermos isn’t released in time, opening it suddenly can cause an explosion.”
Fermentation accelerates when plant-based ingredients or traditional Chinese medicine herbs are heated, generating gas that builds up in sealed bottles. A simple action, like shaking or opening the lid abruptly, can trigger an explosion.
Authorities advise special caution during winter months, when people frequently use thermoses for hot beverages. If the lid is difficult to open, it should be loosened slowly, away from the face and body, to safely release the built-up pressure. Shaking the thermos should be avoided, especially when filled with hot water.
Chinese firefighting authorities also warn that combining hot water and cleaning agents while washing thermoses can increase internal pressure, leading to dangerous explosions. In one extreme case, a man’s thermos exploded so violently that fragments were lodged in the ceiling.
Experts emphasize that while using hot water in thermoses is generally safe, it’s crucial to pre-rinse the bottle with warm water to reduce temperature shock, prevent rapid pressure buildup, and avoid potentially severe injuries.
