What Exactly Is a Wooden Ghani?
Imagine a large mortar and pestle, but made of wood and dedicated to one purpose: slowly crushing oilseeds. This is the essence of a wooden ghani, also known as a 'chekku' or 'kolhu' in various parts of India. For centuries, this was the primary method
for extracting oil from seeds like sesame, groundnut, and coconut. The process is beautifully simple and slow. Oilseeds are placed into a large wooden bowl (the mortar), and a heavy wooden pestle grinds them in a continuous, low-speed rotation. In the past, this was powered by bullocks; today, it is often a motor set to a very low RPM. The key is the slow, gentle crushing which generates minimal friction and therefore, very little heat.
The Number One Enemy: Heat
To understand why the low-heat ghani method is so important, it helps to look at its modern counterpart: industrial oil refining. Most commercially available cooking oils are produced for maximum yield and shelf life, not maximum nutrition. This process often involves high-speed mechanical pressing that generates intense heat, followed by washing the seed pulp with chemical solvents like hexane to extract every last drop of oil. The crude oil is then heated to temperatures that can exceed 200°C for bleaching and deodorizing. While efficient, this high-heat, chemical-heavy process can degrade the oil, destroying sensitive vitamins, altering its natural flavour, and even creating harmful compounds.
Preserving the Natural Fat Balance
Oils are made up of different types of fatty acids: saturated, monounsaturated, and polyunsaturated (like omega-3 and omega-6). This combination is often referred to as the oil's fatty acid profile. High temperatures, such as those used in industrial refining, can damage these delicate fat structures, particularly the polyunsaturated fats. This process, called oxidation, not only reduces the oil's nutritional value but can also lead to the formation of unhealthy trans fats. The wooden-ghani method, by keeping temperatures consistently low (typically below 40-45°C), avoids this thermal degradation. The wood itself helps absorb any friction heat. As a result, the oil retains its natural, original balance of fatty acids, just as they exist in the seed.
Protecting Powerful Antioxidants
Sesame oil is naturally rich in powerful antioxidants, especially the lignans sesamol and sesamin, as well as Vitamin E. These compounds are prized for their ability to fight cellular damage caused by free radicals in the body. However, these beneficial compounds are also highly sensitive to heat. The high-temperature refining process can significantly reduce or destroy them. The gentle, cold-pressing action of the wooden ghani ensures these antioxidants are preserved and remain in the final oil, delivering their full health benefits. Studies show that cold-pressed oils retain significantly higher levels of antioxidants compared to their hot-pressed, refined counterparts.
A Choice for Quality Over Quantity
The slow, low-yield nature of wooden-ghani extraction means the resulting oil is often more expensive than its mass-produced equivalent. The process is a trade-off: modern refining sacrifices nutritional quality for a higher quantity of oil, while the ghani method prioritizes preserving the oil's natural integrity at the expense of yield. Choosing a wood-pressed oil is a decision to opt for an unrefined, nutrient-dense product that retains the natural flavour, aroma, and colour of the original sesame seed. It's a return to a method where the goal was not to create a shelf-stable commodity, but to produce a pure, nourishing food.
