Refined oil is made from oils that have been heated up, which makes them less healthy. Cold-pressed oil is made from oils that are cold-pressed, which is thought to be more healthy.
To get oil from a plant, you need to press it. This process requires a lot of water, which means that the plant’s tissues are very wet. If the water content in the plant is too high, the tissues will be squeezed out and the oil will not be easily produced.
To get oil from seeds, you need to first break them down into their individual parts (protein and fat). This is tricky to do without treatment, so you often have to do it in a way called “stir-frying” which breaks down the proteins and fats so they can be extracted easier.
Everyone often thinks that the temperature is low when pressing raw materials that have been “pre-fried”, but this is not always true. In fact, the pressing temperature can be maintained at about 80 degrees if the raw materials have been pre-fried. However, if the raw materials have not been pre-fried, the pressing temperature can reach over 200 degrees, but this has little impact.
The quality of the oil that comes out of a refinery is affected the most by the quality of the raw oil that is used. If the raw oil is of poor quality, the refinery will have to work to correct the problems with the oil, which can involve a number of processes.
Deacidification is also needed to reduce the acidity of the oil. This is mainly done to ensure the oil is fresh and has not been stored in a bad condition. If the oil has a low acidity, it can be deacidified without needing to do any other processing. One process that is needed is degumming, which is used to remove any glues or impurities from the raw materials. This will improve the appearance of the oil, make it more durable, and make it easier for subsequent refineries to work with. Decolorization removes the color from the oil to make it look less dark. This is done to make the oil look more like a “normal” oil, which some people find more pleasing to use.
Deodorization is the process of removing unpleasant smells from the oil. Many oils have a natural smell, but some smells can be removed by deodorization. This can be done at a high temperature, which is usually around 220-250 degrees. Dewaxing is the removal or reduction of any waxes from the oil. This is done to improve the quality and consistency of the oil.
Refining is the process of removing impurities from raw materials to make a more pure product. Different processes are needed depending on the quality of the raw materials.