It is recommended to choose a vacuum sealed can with excellent sealing and light-proof properties for short-term storage of coffee powder; while coffee beans can maintain stability for a long time in a vacuum sealed can or metal can.
Food packaging grade tinplate sheet is not easy to release harmful substances at room temperature, but whether it will release heavy metal elements such as lead and cadmium under high temperature conditions is worrying. High temperature may decompose the metal surface coating, resulting in food contamination.
Metal tin (Sn) is a soft silver-white metal at room temperature with good ductility and chemical stability. Its resistivity is about 1.09×10−7Ω⋅m, which is slightly higher than copper and silver, but still in the range of typical metal conductors. The presence of tin will not only not weaken the conductivity of the steel plate, but also protect the continuity of the conductive layer due to its uniform coverage.
In Europe, the use of aerosol tin cans is strictly controlled, but not completely banned.
In the United States, the use of aerosol tin cans is also not completely banned, but the U.S. Environmental Protection Agency (EPA) strictly regulates aerosol tin cans products containing greenhouse gases.
Products suitable for tinplate aerosol cans:
1. Cleaning products
2. Cosmetics and personal care products
3. Industrial and home maintenance products
4. Pesticides and deodorants
Substances that cannot be contained in tinplate aerosol cans:
1. Highly corrosive acidic and alkaline substances
2. Gases with particularly high pressures
3. Strong oxidants or highly volatile substances
The main component of tin plate cans is steel, and the surface plating is pure tin. Tin is the preferred material for plating because of its corrosion resistance. Compared with steel, tin can effectively resist the erosion of moisture, oxygen, and acidic substances, prevent the can body from rusting, and thus protect the safety of the contents.
If the tin layer of the tin plate sheet is damaged or scratched, the exposed iron part will lose the protection of the tin layer and be directly exposed to the air. These exposed iron will quickly oxidize when encountering moisture and oxygen in the air to form rust.
Temperature is one of the important factors affecting metal migration. The tin in tinplate cans is relatively stable at room temperature, but when the temperature is above 100°C, the activity of tin may increase, especially under acidic conditions, heating may cause higher tin migration.
Tinplate is the most common material in the current production of candy cans. Tinplate is essentially a tin-plated thin steel plate with good oxidation resistance and corrosion resistance. Because the surface of tinplate is coated with a layer of tin, it can effectively isolate air and moisture to prevent candy from getting damp and deteriorating.
Metal cans have a relatively good sealing effect on aroma. When unopened, the aroma of coffee is basically sealed in the can body and will not volatilize excessively.
