The Difference Between Hot Pressing And Cold Pressing
Hot pressing, also called cooked pressing in some places, means that the oil is heated at high temperature before oil extraction, so that a series of changes will occur inside the oil: destroying oil cells, promoting protein denaturation, reducing oil viscosity, etc., so that it is suitable for pressing oil and common oil extraction process to improve oil yield.
The oil extracted by this process has a pure taste and a strong oily fragrance, especially sesame and peanuts, which are rich in oil, are even more fragrant. However, the color of the oil squeezed out by this process is darker, the acid value rises, and fried things are easy to stagnate. And some nutrients in the oil (vitamin E, sterols, carotenoids, etc.) will be lost in the high temperature generated by hot pressing.
The cold pressing method, also known as the raw pressing method, refers to an oil extraction process in which the oil is not heated before pressing, or is slightly heated, and is sent to an oil press at a low temperature for pressing. The cold pressing method is generally processed in an environment below 60°C. In order to improve the quality of cold-pressed oil, the raw materials for oil-pressing generally need to be carefully selected. The oil extracted by cold pressing method has low oil temperature, low acid value and high quality.
The natural flavor and color of the oil are preserved in the cold-pressed refined oil, and the nutrients in the oil are completely preserved. The degree of protein denaturation is low, and it is easier to comprehensively utilize the protein. Generally speaking, the smoke point of cold-pressed oil is low, it is not easy to smudge, and the color is clearer, and the color is better than hot-pressed oil. However, because cold-pressed oil has not been steamed and fried, the water content in the oil is unstable, which is not conducive to long-term storage. Secondly, the aroma of the oil is not as strong as the hot-pressed oil. If the hot-pressed oil is "strong fragrance", then the cold-pressed oil is "light fragrance".
Although the original taste of cold-pressed oil is a choice for a healthy life, the characteristics of oils are different. For example, cold-pressed soybean oil has a beany smell, which is not acceptable to everyone. For another example, cold-pressed sesame oil has a lighter fragrance, which loses the meaning of sesame oil. Therefore, when choosing the required process, it is necessary to comprehensively consider the characteristics of the material and the living habits of local consumers.
