Oil is a vital cooking ingredient that is used in nearly all food preparation. Many people prefer to use cooking oil as opposed to fat because cooking oil is considered a better option in terms of health benefits. Many of you use oil in your day to day food preparation, but, have you ever wondered where the oil comes from? Let’s look a little further into the oil extraction process.
Oil extraction is a term that refers to the process of separating the vegetable oil from its host. Oils are normally contained in plants known as leguminous plants. Therefore, the process of getting the oil from the plant and separating it so that it can be processed is unique to each plant. Oil extraction can be divided into two types: chemical extraction and mechanical extraction methods. Chemical oil extraction entails mixing the source plant with chemicals that separate the plant tissue from the oil. On the other hand, mechanical oil extraction refers to extracting the oil through mechanical processes that do not use chemical solutions. Additionally, there are two types of mechanical oil extraction: expeller-pressed oils and cold-pressed oils.
Expeller pressing is a mechanical oil extraction technique that involves pressing the seeds, nuts or other material that contains the oil, with a heavy object. It is regarded as a crucial mechanical process that uses sheer force to squeeze the oil out of its host plant material. An important, positive aspect concerning expeller-pressed oil is that this form of extraction does not require any chemicals be used in the process.
In most cases, expeller-pressed oils are made with minimal alteration of the plant tissue. There is zero temperature control during this process and the only heat produced is a by-product of the intense pressing. For instance, pressing hard nuts to extract oil is an intensive mechanical process that will result in the production of some heat.
Expeller oil extraction from its very definition is therefore used to extract oil from a non-sensitive source. Plants that do not react with heat are chosen so that any heat produced during the oil extraction process will have minimal effect on the overall quality of the oil produced.
Cold Pressed Oils
In addition to the expeller pressed oils, another type of oil extraction is cold pressing. Cold pressing is used to extract oil from plant sources that are extremely heat sensitive and should not be subjected to heat that exceeds a certain threshold. Such exposure will damage the natural composition of the plant, thereby undermining the quality of oil produced.
Cold Pressed oils are produced in a similar fashion as expeller pressed oils. The plant that contributes the oil is pressed through mechanical means to extract the oil. Be that as it may, cold pressed oils are quite different from expeller pressed since it involves a substantial amount of temperature control. High temperatures can damage the plant tissue and can interfere with the overall quality of the oil produced.
In most cold pressing processes, the temperatures are usually kept below 120 degrees Fahrenheit. This is considered the threshold temperature for extracting oil from heat-sensitive plants. Exceeding this temperature might undermine the flavor, aroma and other similar important qualities of the oil.
No matter what extraction method you choose, it is best to be informed of the characteristics of the plant you choose to extract from. Use expeller-pressing to extract oil from plants that are not heat-sensitive, and use cold pressing to extract oil from heat-sensitive plants.