Rapeseed oil is a common oil used as a vegetable oil option. Rapeseeds have a high content of oil in them. According to Patent Storm, about 40 percent to 45 percent of the weight of the rapeseed is oil. Due to the high rate of oil in the seeds, extracting the oil is common. The traditional method of extracting the oil is through the use of an oil expeller, a machine that crushes the rapeseed to squeeze out the oils.

Clean the rapeseeds by removing any plant material and dirt still attached to the seeds.

Place the rapeseeds in a flaking mill and turn on the mill. The mill has cylindrical rolls that turn in opposite directions to crush or flatten the seeds.

Heat the seeds. Pour the flaked seeds into a multistage cooker. Heat the seeds to 68 to 122 degrees Fahrenheit as a preheat within five minutes. Steam heat to 248 degrees Fahrenheit.

Place the seeds into the oil extractor immediately after heating. The heat will make the oil separate easily from the seeds. Turn on the extractor. The machine crushes the oils out of the seed flakes until there is nothing left coming out of the seeds.