The method of extracting oil from seed product can be can be done in one of two methods: Cold or heated pressing. Each have advantages and disadvantages.
Extracting oil from seed using a low-heat method is termed “co
ld pressing” To create the oil, the seeds or nuts are ground into a paste. That paste is then further mixed in an effort to make the oils better coagulate. Next, pressure is applied to the paste eventually forcing the oil to be removed.
In the cold pressed process oil extraction relies solely on the pressure. No, or very little, heat is added to the paste to assist in the extraction. Cold presses are usually mechanically operated and often consist of a screw device that is tightened against the paste to extract the oils. Cold pressing usually produces a lower-yield, but higher quality of oil.
In some cases, oil is produced using a variation of the with a high-pressure system. This so-called expeller pressed method can create some heat because of the high amounts of friction and added pressures involved. However, no supplemental heat is added in the process. Oil made with the expeller method is often still considered cold pressed. It may be labeled to indicate an expeller was used.
Cold-pressed oil is regulated in different parts of the world. In Europe, in order to earn the label of cold pressed, the oil extraction process must be certified. That certification means the oil extraction never exceeds a certain temperature. Usually that temperature below 100 ° F. The United States does not regulate the oil making processes, so users must perform their own tests to determine if the oil meets standards.
Heated oil extraction is as its name implies dependent on adding heat to the process. The first steps of the process remain the same as cold or expeller methods. But in the heated extraction process, the paste is heated with an outside source. The heat is usually added to the paste using warm water or direct heating elements powered by electricity. In larger operations, heating elements may be driven by natural gas. Adding heat to the paste is shown to increase the amount of oil produced. However, many argue the heating process degrades the quality. Oil created through heating process sometimes loses its color as well.
The extraction choice for oils depends on the type of source material and the final destination for the oils. The advantage of cold pressing oil is usually higher quality. It can be more difficult to cold press some types of seeds and nuts. If more volume is required, turning to his heat press technique will increase the yield. But, heat pressed oil often lacks color and some of the higher quality attributes.