In our daily life, we are faced with two kinds of edible oil production. One is hot pressed oil, the other is cold-pressed oil. Based on this classification, some people will ask which kind of edible oil is better and how to chose the most suitable one to satisfy the various application. Hard to answer this question exactly, for different people have different opinions about the question. Personally, I think both hot pressing and cold pressing have their pros& cons. Here we will discuss this question in detail.
In our daily life, the most common edible oil we use is hot pressed oil. But in recent years with the people’s improved living standard, cold-pressed oil become more and more popular. The main difference between cold and hot pressing does not affect the pressing equipment to a great extent, rather it has implications for the preparation of the input material. Due to the different preparation, the input material has different characteristics in the case of the two pressing methods, which require different press configurations. The configuration and some other settings are basically the differences between press units for cold and hot pressing.
Just as the name implies, the cold pressing means pressing under low temperature, the oilseeds can be pressed without roasting. While hot pressing is pressing under high temperature, the oilseeds are pressed after roasting. So next, we will talk about the question in the following three aspects.
The production process of the two methods is different. The cold pressing of oil seeds does not need any pre-conditioning of the input material, which is pressed directly at room temperature. The oil temperature is low(must below 49℃), and the acid value is also relatively low. So there is no need to refine. We should get the oil products after precipitation and filtration. While different from the cold pressing, when producing some seeds oil we had better heat the seeds up or add chemicals to help the oil keep its fragrant and improve the oil yield, like sesame and peanut. Also, the color of the raw oil is relatively dark after high-temperature treatment, the acid value will rise, so the crude oil can be edible only after refining. Refining means removing the impurity, reducing the stone particles content and stabilizing the fatty acid value by using the metering pump, oil filter, vacuum pump and so on.
To be frank, cold pressing oil is safer and nutrient. It could avoid the adverse effects caused by traditional high temperatures, retain the physiologically active substance and its original taste and flavor. It is a pretty good choice for a healthy life. Compared with the cold-pressed oil, hot pressed oil will lose some nutrients after high-temperature processing. But some oilseeds are different, which have to be roasted under high temperature before pressing. For example, soybean oil contains beany flavor, high erucic acid, rapeseed oil contains biting taste, cottonseed is with toxin gossypol, deteriorating oil material has aflatoxin, etc. They all need refining to remove the taste. Besides, hot pressing is a must suitable for some oilseeds such as sesame and peanut, hot pressing can keep the flavor and fragrant of the oil, at some time, improve the taste and oil yield.
Cold-pressed oil is nice and light in color. There is no foam when frying. But it’s not so fragrant, and may have unripe flavor, tasting not so good. Hot pressed oil has a pure flavor. It’s fragrant, especially sesame and peanut which have rich oil. The disadvantage is that there will be foam when frying if without processing. But just simple treatment can solve this problem.
As consumers, if you like fragrant flavor, you can purchase hot pressed oil. The edible vegetable oil we usually use in our life is hot pressed oil. But in recent years, people have a larger demand for healthiness and quality so the cold pressed oil is becoming more and more favored. It doesn’t destroy the cell of the grease and linoleic acid tissue and is more green and healthy. For cold pressing, we usually use hydraulic oil press, while generally, we use screw oil press for hot pressing.
When you are choosing an oil press machine, don't forget to take these factors into account. If you want to produce quality oil with a very little amount, you are going to buy a cold press oil machine. However, if you are going to produce a large amount of oil in a very short time, you should buy hot press oil machines instead.
A hot pressing machine is best if you are looking for large amounts of oil. The hot pressing machine is the best choice on the subject of extracting extensive quantities of oil out of oil-bearing materials. By heating the seed paste, it is possible to let the coagulation process much faster thereby making it simpler to extract a great deal of oil from oil-bearing materials. The other advantage of the hot pressing machines is that they can extract oil at a very short time. For commercial ventures, a hot pressing oil machine is the greatest since quantity affects the profit margin. More oil means more money.
As to the cold pressing, the oil produced by these methods is of great high quality. During cold extraction, ripe fruit or seeds are ground to a paste which is fed into a grinder. As 10 to 15 % of oil will remain in the press cake after milling, this procedure is quite expensive. It is only used for extracting oil from seeds with very high oil content, such as olives and sunflowers. Cold-pressed oils to have a distinct flavor and intense color, whereas refined oils are lighter and usually clearer.