What cannot be filled in a thermos cup

What cannot be filled in a thermos cup
Not suitable for acidic drinks
Stainless steel has a high melting point and will not release harmful substances due to melting at high temperatures. But stainless steel is most afraid of strong acids, and if it is filled with drinks with strong acidity for a long time, it may cause damage to the internal organs.
Not suitable for filling milk
Some people may put hot milk in a thermos, but this practice allows the microorganisms in the milk to rapidly multiply in an appropriate environment, causing spoilage and diarrhea and abdominal pain. Because the acidic substances in milk in high-temperature environments can cause chemical reactions on the inner wall of the thermos, affecting human health.
Not suitable for brewing tea
Tea contains a large amount of tannic acid, theophylline, and various vitamins, making it suitable for brewing with water at around 80 degrees Celsius. And a thermos can soak tea leaves in high temperature, constant temperature water for a long time, just like boiling them over a warm fire. Experts say that tea is not suitable for long-term soaking as it may release heavy metal substances and damage the vitamins in the tea.
Not suitable for soybean milk
The thermos cup is a culture dish for bacteria. It will deteriorate when it meets the rancidity of soybean milk, and will also dissolve the toxic substances in soybean milk, which is harmful to health. Therefore, it cannot be put into the thermos cup.
Not suitable for containing traditional Chinese medicine
However, cooked traditional Chinese medicine dissolves a large amount of acidic substances, which can easily react with the chemicals contained in the inner wall of the thermos. Dissolving them into the soup has adverse effects on human health.
Keep the thermos insulated for a few hours, it's normal
It depends on the situation.
The insulation time of a thermos depends on the quality of the thermos. Generally speaking, a thermos that has been insulated for about 4-6 hours is considered qualified. A thermos with better quality can be insulated for more than 12 hours, while a thermos with lower quality can only be insulated for about 1-2 hours.
To test the insulation time of the insulated cup, ice cubes can be injected at a room temperature of 20 ℃, filled and placed vertically. After 6 hours, the ice cubes do not melt. This indicates that the insulation time of the thermos is at least 6 hours, which is already a high-quality thermos. We added 98 ℃ hot water to the same environment, and after 6 hours, the water temperature was above 60 ℃, which is also considered a high-quality insulated cup.