Mustard oil or Sarson Tel are extracted from mustard seeds. Mustard oil is golden to dark golden brownish color. Mustard oil has unique strong flavor (considered pungent by some) and smell. The first use of mustard seed as source of oil in Indian subcontinent  is mentioned in ancient Sutra literature around 800 B C. However, many scholars belief its use before that as well. Mustard oil is frequently used in Bengali food and other eastern India cuisines. To reduce intense mustard oil flavor, often it is heated until to smoking point before cooking. Sometime, it is cooled down and reheated to get mellow flavors.