Cold pressing and hot pressing are two different pressing processes, both of which belong to the category of physical pressing, and are generally aimed at screw presses. The current new screw oil presses are all multifunctional and fully automatic, and can be cold or hot pressed. The cold pressing process means that the oil is directly fed into the oil press for squeezing without being fried. The press chamber is in a low temperature environment during pressing. The second hot pressing means that the oil is fried to heat to stimulate oily cells and reduce the viscosity of the oil. It will enter the screw oil press for squeezing after the temperature, and the press chamber is in a high temperature environment during squeezing.
Cold-pressed oil and hot-pressed oil have their own characteristics. Cold pressing needs to be pressed twice to be able to squeeze clean, because the oil has not been fried until it contains a lot of water, even if the screw press is pressed harder, it is impossible to press it again. Squeeze completely clean. The color of cold-pressed oil is light and it looks good, and the loss of protein and unsaturated fatty acids in the oil can be retained to the greatest extent when pressed at low temperature. However, cold-pressed oil contains too much water and has not been fried at high temperature, so it has no hot-pressed oil flavor and has a shorter storage time than hot-pressed oil. After the hot-pressed oil is fried, most of the water has been evaporated, so the hot-pressed oil tastes fragrant and has a long storage time. But the color of hot pressed oil is darker, not as good as cold pressed oil. The operator of the oil press can choose the pressing process according to the taste of the local people.