Cold pressing oil extraction refers to the pressing method that oil plants before pressing are not heated or kept in low temperature state before being fed into the oil press. Cold pressing is generally in the temperature of less than 60℃. Cold pressed oil retains the natural flavor and color of oil plants, complete preserves the physiological active substances with lower protein denaturation degree
COLD PRESSING METHOD
Cold pressing oil extraction refers to the pressing method that oil plants before pressing are not heated or kept in low temperature state before being fed into the oil press. Cold pressing is generally in the temperature of less than 60℃. Cold pressed oil retains the natural flavor and color of oil plants, complete preserves the physiological active substances with lower protein denaturation degree and conducive to the comprehensive utilization of protein. Raw materials of cold pressed oil must be carefully selected, otherwise it will affect the quality of cold pressed oil. Generally speaking, the smoke point of cold pressed oil is low and the moisture content is not stable, which is not conducive to long-term storage.
Cold pressed oil has light color and smell, it keeps the original flavor of oil plants, green and environmental protection. Especially suitable for pressing organic plants and economic crops with high added value, such as olive, walnut, grape seed, linseed oil and other oil crops.
The friction caused by the pressure does increase the temperature of the product, this is not high. Manufacturers must keep it within a certain degree range to be able to claim that the oil is cold pressed. For instance, to obtain virgin olive oil oil without damaging the properties it cannot exceed 25 ° C.
What are the steps?
1. The process begins with the filtering stage, in which the seeds will be passed through a series of spaces with air propulsion systems. This process removes any impurities.
2. Milling: The nuts, seeds, or fruits are ground into a paste using heavy granite millstones or modern stainless steel presses, which are found in large commercial operations.
3. Pressing: The semi-solid paste is slowly stirred, often with a rotating screw which encourages the oil to separate from the solid parts and clump together. Once this happens, pressure is applied to force the oil out. It is one of the most important moments of the whole process, since this pressure may increase the temperature of the dough. If it exceeds a certain temperature, the oil may lose some of its properties.
4. Filtering: The pressed oil goes through a series of filters that separate small pieces of peel or pulp of the fruit from the oil. The final part of this filtering process involves passing the oil through a cloth or paper to ensure that all impurities are removed from the oil.
This method of oil extraction requires the use a lot of fruits and seeds (e.g. for one litre of argan oil up to 30 kg of seeds will be used), the discarded parts do not go to waste, they are used for animal feeds or fertilizers.
5. Once the filtering process is complete, a decantation process is carried out. Any remaining sediement is separated from the oil by the simple force of gravity. Thus, a 100% pure and natural oil that retains all its properties will be obtained.