Vegetable oil olive, coconut etc.), and it is preferred by most "health-food" customers in the United States and in Europe. There are several different types of mechanical extraction. Expeller-pressing extraction is common, though the screw press, ram press, and ghani (powered mortar and pestle) are also used. Oilseed presses are commonly used in developing countries, among people for whom other extraction methods would be prohibitively expensive; the ghani is primarily used in India. The amount of oil extracted using these methods varies widely, as shown in the following table for extracting mowrah butter in India: The processing of vegetable oil in commercial
Butter lamp safety, butter lamps are sometimes restricted to a separate courtyard enclosure with a stone floor. Externally, the lights are seen to banish darkness. Conceptually, they convert prosaic substance into illumination, a transformation akin to the search for enlightenment. Esoterically, they recall the heat of the "tummo yoga" energy of the Six Yogas of Naropa, an important text for Kagyu, Gelug, and Sakya schools of tantric Buddhism. Butter lamp Butter lamps (; ) are a conspicuous feature of Tibetan Buddhist temples and monasteries throughout the Himalayas. The lamps traditionally burn clarified yak butter, but now often use vegetable oil or vanaspati