How They Are Made: A Tale of Two Processes
The primary difference between cold-pressed and refined oils lies in their extraction process. Cold-pressed oils are made by simply crushing seeds or nuts and forcing out the oil through pressure. This is often done using traditional methods like a wooden
press ('ghani' or 'chekku'), where the temperature is kept low to preserve the oil's natural character. The process is mechanical, slow, and yields less oil, but it retains the natural flavour, aroma, and nutrients of the seed. Refined oils, on the other hand, are produced on an industrial scale. The process often involves using chemical solvents like hexane to extract the maximum possible oil from the seeds. This crude oil then undergoes multiple stages of processing—degumming, neutralizing, bleaching, and deodorizing—at very high temperatures to remove impurities, odours, and colours. The result is a neutral, uniform oil with a long shelf life.
The Nutrient and Flavour Divide
Because cold-pressing is a gentle, low-heat process, the resulting oils retain most of their natural goodness. They are rich in antioxidants, vitamins like Vitamin E, and essential fatty acids. This minimal processing also means the distinct flavour and aroma of the groundnut, mustard, or sesame seed shine through, adding a characteristic taste to dishes. In contrast, the high-heat and chemical treatments used in refining strip the oil of many of these beneficial compounds. The process of deodorization, for instance, removes not just the natural aroma but also many of the antioxidants. What you are left with is a bland, flavourless oil that serves as a neutral cooking medium but offers little in terms of micronutrients or taste enhancement.
The Smoke Point Showdown: What Matters for Indian Cooking?
A common argument for refined oils is their higher smoke point—the temperature at which an oil begins to smoke and break down, potentially releasing harmful compounds. Refined oils have a high smoke point because the very compounds that would smoke have been stripped out during processing. This makes them seem ideal for high-heat cooking like deep frying. However, for the majority of daily Indian cooking—such as making tadka, sautéing vegetables, or preparing parathas—the heat rarely exceeds the smoke point of common cold-pressed oils. For instance, cold-pressed groundnut oil has a smoke point of around 160°C, which is sufficient for most everyday frying. Refined oils are truly necessary only for repeated deep frying at very high temperatures, a practice that is less common in daily home cooking.
Making the Choice: Which Oil for Which Dish?
The best approach is not to declare one oil a universal winner, but to use the right oil for the right purpose. Many Indian households are returning to the traditional practice of keeping a few different oils for various culinary needs. Here’s a simple guide: For Tadkas, Dals, and Sabzis: Cold-pressed oils like mustard, groundnut, or sesame oil are excellent. Their distinct aromas enhance the flavour of the spices and the overall dish. For Deep Frying Puris and Pakoras: If you deep fry occasionally, a cold-pressed groundnut or coconut oil on a medium flame works well. For frequent, high-heat deep frying, a refined oil might be more stable, but it's a trade-off against nutrition. For Chutneys, Drizzling, and Pickles: The rich flavour of cold-pressed oils makes them perfect for raw applications or as a finishing touch to add aroma and taste. Sesame oil, in particular, is traditionally used in South Indian pickles.
