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1.
After harvesting rapeseed planted in rural areas, after drying and simple dust removal, it is pulled out from nearby oil and processed into rapeseed oil. This process is very simple. First, the rapeseed is crushed, and then the oil is squeezed. Therefore, pressed oil is a kind of crude oil containing many impurities. Because this is rapeseed oil squeezed by local soil method, it can be said that the "original ecology" is preserved because these shears are relatively simple and cannot remove these impurities. After cooking and oiling, the temperature at which smoke begins is called "smoke point". The higher the smoke point, the less likely the oil is to smoke, and the lower the smoke point of the oil, the easier it is to smoke.
Rapeseed oil squeezed by rural soil is not refined, so it contains a lot of impurities, so the smoke point is very low. The level of edible softening point is closely related to the content of impurities, which can be increased by purification. For example, the smoke point of soybean and peanut crude oil is usually about 150- 160 degrees, which can reach 230 degrees or higher after refining.
2. Other reasons for the large oil fume.
Another reason is that rapeseed oil is easier to ignite than other oils. Therefore, if flammable oil is heated, or if the pot used at home is not an iron pot, the iron pot itself will produce fine debris, which is also easy to produce lampblack. Rural oil presses are relatively simple, so they can only be filtered simply and have no purification technology.
3. The difference between homemade oil and refined oil
Rapeseed oil extracted by soil method contains impurities. The freshly squeezed oil, which is basically dark, is generally opaque and has a lot of bubbles. Even when rapeseed oil is almost consumed, many impurities remain at the bottom of the oil pot. Because the edible oil bought in the supermarket is refined commercial oil, it won't smoke a lot, because refining is to remove all kinds of impurities in the oil. Therefore, such commercial oil not only has high appearance value, but also has little smoke when cooking.
Therefore, because the rapeseed oil squeezed in rural areas will leave a lot of impurities in the grinding process, and the iron pot itself. So there is a lot of oil smoke.