A thermos can hold coffee, but attention should be paid to material selection and time control, as follows:
1. Material and Chemical Reaction
Stainless steel insulated cup: It can hold coffee in the short term (2-4 часы), but it should be avoided to store for a long time. Tannic acid in coffee may corrode stainless steel liners, leading to the precipitation of metal elements (such as chromium and nickel), which may affect health after long-term use.
Ceramic/glass lined insulated cup: safer, less likely to react with coffee ingredients, suitable for long-term use.
2. The influence of time and temperature
Hot coffee: It is recommended to drink it within 4 часы. Exceeding 4 hours may lead to an increase in coffee acidity, and the stainless steel liner may release harmful substances.
Cold brewed coffee/iced coffee: Due to low temperature inhibition of oxidation, the flavor is more stable, and the storage time can be appropriately extended, but it still needs to be consumed on the same day.
Milk containing coffee (such as latte): Due to the perishable nature of dairy products, it should be consumed within 1-2 часы.
3. Safety hazards
Gas pressure issue: Hot coffee in a sealed insulated cup may generate high pressure due to temperature changes, posing a risk of splashing or explosion when opening the lid.
Fermentation additives: If fermented substances such as goji berries and red dates are added to coffee, they may produce gases that increase pressure and exacerbate the danger.
4. Cleaning and maintenance suggestions
Timely cleaning: Coffee residues can easily breed bacteria and leave off odors. It is recommended to immediately clean with a neutral detergent after use to avoid dirt accumulation.
Special insulated cup: If you frequently serve coffee, it is recommended to use ceramic inner insulated cups or stainless steel coffee cups designed specifically for coffee to reduce material impact.
5. Summary
Short term use of stainless steel insulated cups for coffee is feasible, but strict time control is required and non-metallic inner container should be prioritized. If pursuing safety and flavor, it is recommended to use glass insulated cups or coffee specific cups, and follow the principle of “ready to drink”.
