An Ancient Tradition of Purity
Long before refined oils lined supermarket shelves, kitchens across South India relied on a simple yet effective technology: the 'ghani', also known as 'chekku' or 'kolhu'. This traditional oil press, essentially a large mortar and pestle, was a common
sight in villages. Historically powered by bullocks walking in a slow, steady circle, the ghani would crush seeds like sesame, groundnut, or coconut to release their oil. This method was not just about extraction; it was about preservation. The entire process was designed to handle the seeds gently, ensuring the oil retained its natural character, from flavour to nutritional integrity. This tradition, which was a way of life until about 50 years ago, is now being revived as consumers seek healthier, more authentic food choices.
The Science of 'Cold-Pressing'
The term 'cold-pressed' is key to understanding the ghani's superiority. The process involves crushing the seeds mechanically without applying external heat. In a wooden ghani, a large wooden pestle rotates slowly inside a wooden chamber, grinding the seeds through immense pressure. The slow rotation is crucial. Unlike modern metal expellers that spin at high speeds and generate significant friction and heat, the wooden ghani operates at a low RPM. Wood is a natural insulator, so it absorbs the minimal heat produced, keeping the oil's temperature below 40-50°C. This gentle, low-temperature process ensures the oil is not just extracted, but extracted with its molecular structure and delicate micronutrients intact.
Heat: The Enemy of Antioxidants
The main advantage of keeping temperatures low is the preservation of antioxidants. Sesame oil is naturally rich in powerful antioxidants, primarily the lignans sesamin and sesamol, as well as Vitamin E (tocopherol). These compounds are highly sensitive to heat. Industrial refining processes often involve high temperatures and chemical solvents to maximize yield and create a neutral, long-lasting product. However, studies show that pressing temperatures above 60°C, and especially over 90°C, cause a significant reduction in total phenol and tocopherol content. Research confirms that sesamin and sesamolin levels degrade when exposed to high heat during roasting or refining. By avoiding high temperatures, the wooden ghani method ensures these vital antioxidants, which help combat cellular damage and inflammation, are retained in the final oil.
The Purity of a Chemical-Free Process
Beyond heat, the wooden ghani method is valued for being entirely free of chemicals. Industrial refining often uses chemical solvents to extract every last drop of oil, followed by bleaching and deodorizing agents to create a uniform product. This not only strips away nutrients but also carries the risk of leaving solvent residues in the oil. The wooden ghani process is purely mechanical. After the oil is pressed, it is typically left to rest for a few days, allowing any sediment to settle naturally. It is then filtered through cloth, a simple physical step that clarifies the oil without any chemical intervention. The result is a pure, unrefined oil that is exactly as nature intended.
Flavour and Aroma You Can't Refine
The nutritional benefits are matched by the superior sensory qualities of ghani-pressed oil. The rich, nutty aroma and distinct flavour of cold-pressed sesame oil are a direct result of the natural compounds preserved during extraction. These are the very characteristics that are deliberately removed during industrial deodorization to create a bland, neutral oil. For this reason, many families in India are returning to chekku oil, recognizing that the authentic taste of traditional dishes, from a flavourful sambar to a simple podi, is deeply connected to the quality and character of the oil used. This return isn't just about health; it's about reclaiming the authentic flavours of home cooking.
