Coffee vacuum freeze dryer

Coffee vacuum freeze dryerRaw material preparation: First, pour the extracted liquid coffee (coffee extract) into a large metal tray.

Rapid freezing: Send the tray into the freezer compartment of the freeze dryer and lower the temperature (usually -30 ℃ to -50 ℃).

Formation of ice crystals: In this ultra-low temperature environment, the water in coffee liquid rapidly solidifies, forming small ice crystals. The speed and temperature control of freezing are crucial as they determine the size of ice crystals. Slow freezing can form large ice crystals, which may damage the microstructure of coffee; Rapid freezing (deep freezing) forms small ice crystals, which can better lock in volatile flavor compounds.

Coffee vacuum freeze dryerIn a highly vacuum environment, by heating frozen coffee, the ice crystals inside are directly sublimated into water vapor, which is then captured and removed by a cold trap to obtain dried coffee products.

The huge advantages brought by this principle are:

Preserve flavor and aroma: the whole process is carried out at low temperature, avoiding the destruction of volatile aromatic substances in coffee by high temperature (compared with the high temperature of spray drying).

Maintain physical structure: The sublimation process leaves behind a porous sponge like structure. This allows freeze-dried coffee to quickly penetrate into every pore during rehydration, resulting in a fast dissolution rate.

Preventing ingredient damage: Low temperature prevents the denaturation and oxidation of thermosensitive substances, better preserving the original taste of coffee.

Long shelf life: The moisture content inhibits the growth of microorganisms, allowing the product to be stored for a long time.

Because of these advantages, the freeze-drying technology can produce high-quality coffee that is far superior to the traditional instant coffee (spray drying method) in flavor and convenience. After the coffee is frozen, a powerful vacuum pump will be started in the freeze-drying bin to reduce the air pressure in the bin to a very low level (usually less than 0.6 Pa, far lower than the triple point pressure of water)