What is Wooden-Ghani Extraction?
Known for centuries in India as 'chekku', 'kolhu', or 'ghani', this traditional method uses a large wooden pestle that rotates slowly inside a wooden mortar to crush oilseeds. Historically powered by bullocks and now often by slow-speed motors, the system
is designed for one crucial purpose: to press oil without generating significant heat. The seeds, whether sesame, coconut, or groundnut, are crushed gently, allowing the oil to seep out naturally. This oil is then typically left to rest for sediments to settle before being cloth-filtered, a process devoid of any chemical intervention. The result is a pure, unrefined oil that retains the seed's original colour, aroma, and nutritional profile.
The Enemy of Freshness: Heat and Oxidation
To understand why the ghani method is so effective, it's important to know what degrades oil. The primary culprits are heat, light, and oxygen, which cause oxidation. This chemical reaction breaks down the fatty acids in the oil, leading to rancidity, loss of flavour, and destruction of valuable nutrients. Modern industrial extraction methods often use high heat and chemical solvents like hexane to maximize yield. While this process is efficient and creates a uniform product with an artificially long shelf-life, it comes at a nutritional cost. The high temperatures can destroy the very compounds that naturally protect the oil and offer health benefits.
Sesame Oil’s Secret Weapons: Sesamol and Sesamin
Sesame oil is naturally gifted with powerful antioxidants, primarily lignans called sesamol, sesamin, and sesamolin. These compounds are the oil's built-in preservation system. They are exceptionally effective at fighting oxidation, which is why sesame oil is known for its impressive stability compared to other vegetable oils. When sesame seeds are processed at low temperatures, as in a wooden ghani, these antioxidants are preserved. The slow crushing ensures that the oil's temperature remains low, keeping these delicate but powerful molecules intact and ready to protect the oil from going rancid.
A Tale of Two Oils: Ghani vs. Refined
When you compare a bottle of wood-pressed sesame oil to its refined counterpart, the differences are stark. Ghani-pressed oil is often darker, with a rich, nutty aroma and flavour. Refined oil is typically pale, odourless, and tasteless. This neutrality is achieved through processes like bleaching and deodorising, which strip the oil of its natural character along with its antioxidants and vitamins. While refining creates a product that lasts longer on the shelf due to the removal of reactive compounds, it's a shelf-life achieved by subtraction. In contrast, the longevity of ghani-pressed oil comes from addition—the retention of its natural protective antioxidants.
More Than Just Shelf-Life
The benefits of preserving these antioxidants go beyond preventing spoilage. Sesamol and sesamin are celebrated for their health-promoting properties, including anti-inflammatory and heart-protective effects. The wooden-ghani method also preserves other vital nutrients like Vitamin E, another potent antioxidant, and essential fatty acids that are crucial for overall health. By choosing oil extracted through this ancient, gentle process, consumers are not just getting a product that stays fresh longer naturally, but one that delivers the full spectrum of the sesame seed's nutritional goodness, just as nature intended.
