Cold-Pressed vs Wood-Pressed vs Refined Oil: What Do These Terms Actually Mean?

Walk into any grocery store today and the cooking oil aisle will confront you with a wall of claims: cold-pressed, wood-pressed, kachi ghani, expeller-pressed, virgin, extra-virgin, filtered, unrefined, refined, double-refined. Each label implies something better than the last, yet very few of them come with a plain-language explanation of what they actually mean or why the difference should matter to you.

The truth is that the method used to extract oil from seeds, nuts, or grains determines almost everything - the nutritional value, the flavour, the cooking performance, the shelf life, and ultimately the effect it has on your health. This guide cuts through the marketing noise and explains exactly what each term means, how the processes differ at a technical level, and which oils are actually worth buying.

How Cooking Oil Is Made: The Three Fundamental Methods

All cooking oil starts the same way - with an oil-bearing seed, nut, or grain: mustard seeds, groundnuts, sesame seeds, sunflower seeds, coconut flesh, soybean, and so on. The oil content of these raw materials ranges from about 20 percent (soybean) to over 60 percent (coconut). Extracting that oil can be done in three fundamentally different ways, each with very different implications for what ends up in the bottle.

• Mechanical pressing - the raw material is physically compressed to squeeze out the oil. No solvents, no chemicals. This category covers both cold-pressed and wood-pressed methods.

• Solvent extraction - the raw material is bathed in a chemical solvent (typically hexane, a petroleum derivative) that dissolves the oil, which is then separated from the solvent by evaporation. Used industrially because it extracts far more oil from the same raw material than pressing alone.

• Refining - a series of industrial treatments applied after extraction to neutralise flavour, extend shelf life, and standardise colour. Refining can follow either mechanical pressing or solvent extraction, though it most commonly follows the latter.

The majority of cooking oil sold in India today - labelled simply as "refined sunflower oil," "refined soybean oil," or "refined palm oil" - has been through all three stages. The oil you see in that clear plastic bottle was likely hexane-extracted and then heavily refined before it ever reached a shelf.

Cold-Pressed Oil: What the Term Actually Means

Cold-pressed refers specifically to a temperature constraint during mechanical pressing - the oil is extracted without allowing the temperature to exceed a defined threshold, typically 49°C (120°F) in most international standards, though Indian standards vary by certification body. The reasoning is straightforward: heat destroys nutrients. Many of the vitamins, antioxidants, and volatile aromatic compounds in seeds and nuts are heat-sensitive, and they degrade rapidly as pressing temperatures rise.

In practice, all mechanical pressing generates some heat through friction - the more force and speed applied, the more heat produced. Cold-pressing controls this by running the press slowly, in short batches, sometimes with water cooling on the press head, to ensure temperatures stay within the specified range.

What is preserved as a result is significant. Cold-pressed oils retain their natural Vitamin E (tocopherols and tocotrienols), polyphenol antioxidants, chlorophyll, carotenoids, phospholipids, and the full spectrum of volatile aromatic compounds responsible for their characteristic flavours. These compounds are not mere flavour agents - they are bioactive, contributing to the oil's anti-inflammatory, antioxidant, and cardiovascular benefits.

One important clarification: the term "cold-pressed" says nothing about the equipment used. A modern stainless-steel expeller press running under controlled temperature conditions qualifies as cold-pressed. So does a centuries-old wooden ghani. The term defines the temperature outcome, not the process that achieves it.

Wood-Pressed (Kachi Ghani) Oil: India's Traditional Method

Wood-pressed oil - known as kachi ghani oil in Hindi, chekku oil in Tamil, and ghani oil across much of India - goes further than the cold-pressed specification in both its method and its results. The traditional ghani is a large wooden mortar with a wooden pestle, historically rotated by bullocks walking in a slow circle around the press, though today most are motor-driven. Seeds are fed into the mortar in small batches and pressed gradually over an extended period.

The critical differences from modern mechanical cold-pressing are speed and contact material. The ghani rotates far more slowly than any industrial press - 5 to 8 revolutions per minute compared to 60 to 100 in modern expeller presses. This generates almost no friction heat, reliably keeping temperatures below 40°C without any active cooling requirement. It also results in a lower oil yield per kilogram of raw material - approximately 35 to 40 percent recovery compared to 45 to 50 percent from faster mechanical pressing and over 98 percent from solvent extraction. This lower yield is part of why wood-pressed oil is more expensive, and it is not a limitation - it is evidence that the process prioritises quality over volume.

The wooden contact surface itself may also play a role. Traditional knowledge holds that the wood imparts beneficial properties to the oil - and while this is difficult to study rigorously, it is known that wood has natural antioxidant properties and that certain tannins from wood can migrate into the oil during pressing, potentially contributing to its flavour and stability.

The result is an oil that is genuinely unrefined, deeply flavoured, and nutritionally complete. Wood-pressed mustard oil retains its allyl isothiocyanates - the compounds responsible for its characteristic heat and its antimicrobial properties. Wood-pressed groundnut oil retains its full Vitamin E content and its naturally occurring resveratrol. These are not minor differences. They represent the entire nutritional value proposition of the oil.

Our Wood-Pressed Yellow Mustard Oil and Wood-Pressed Groundnut Oil are both extracted using this traditional kachi ghani method - slow-pressed, unrefined, and bottled without any chemical treatment.

Refined Oil: What Happens Inside the Factory

Refining is not a single process - it is a sequence of six or more industrial treatments, each designed to remove something the manufacturer considers undesirable. Understanding what is removed, and why, makes the nutritional consequences of refined oil clear.

Step 1 - Solvent Extraction

Most refined oil production begins not with pressing but with hexane extraction. Crushed seeds are mixed with hexane, which dissolves the oil. The hexane is then evaporated off and theoretically recovered, but trace residues remain in the crude oil. Hexane is classified as a neurotoxin in occupational exposure contexts and its trace presence in edible oil, while considered within regulatory limits, is a genuine concern for daily consumers.

Step 2 - Degumming

Water or acid is added to the crude oil to precipitate out phospholipids (gums) including lecithin. These phospholipids are actually nutritionally valuable - they are sold separately as supplements - but they cause cloudiness and reduce shelf life, so they are removed.

Step 3 - Neutralisation (Alkali Refining)

Sodium hydroxide (lye) is added to neutralise free fatty acids, which are removed along with fat-soluble vitamins and carotenoids that bind to the soap formed in this step. This stage removes a significant portion of the oil's natural Vitamin E and Vitamin A precursors.

Step 4 - Bleaching

The oil is filtered through activated clay to remove remaining pigments, including chlorophyll and carotenoids. The result is a pale, colourless oil. Any remaining trace antioxidants are largely destroyed or adsorbed in this stage.

Step 5 - Deodorisation

Steam is passed through the oil at temperatures between 200°C and 270°C under vacuum to vaporise and remove all odour-causing volatile compounds. This is the most nutritionally damaging step. At these temperatures, the remaining polyunsaturated fatty acids partially oxidise, creating lipid peroxides, aldehydes, and trace trans fatty acids. The natural antioxidants that would have protected the oil during cooking are now entirely absent. The oil is shelf-stable and flavour-neutral - but nutritionally inert and structurally compromised.

What you cook with when you use refined vegetable oil is not a food in any meaningful nutritional sense. It is a purified fat delivery system with no vitamins, no antioxidants, no phytochemicals, and residual oxidative damage baked in before it even reaches your pan.

Side-by-Side Comparison: Nutrition, Flavour, and Cooking Use

Smoke Points and Cooking Suitability

The smoke point of an oil - the temperature at which it begins to smoke and break down - is a practical concern for Indian cooking, which involves high-heat techniques like tarka, bhuna, and deep frying. A common misconception is that unrefined oils have dangerously low smoke points that make them unsafe for Indian cooking. This is not accurate.

• Wood-pressed mustard oil: approximately 250°C - excellent for all Indian cooking including deep frying

• Wood-pressed groundnut oil: approximately 160°C unrefined - suitable for medium-heat cooking, tadka, and light frying

• A2 Bilona Ghee: approximately 250°C - among the highest smoke points of any traditional fat, ideal for high-heat cooking

• Refined sunflower oil: approximately 227°C - high smoke point, but the refining process that achieves it also removes all nutritional value

Importantly, smoke point is not the only measure of cooking stability. An oil's natural antioxidant content significantly affects how quickly it oxidises during cooking. Wood-pressed oils, rich in natural antioxidants, are more resistant to oxidative degradation at comparable temperatures than refined oils stripped of those same antioxidants. The real-world cooking stability of a quality wood-pressed oil is considerably better than its smoke point number alone suggests.

For the highest-heat cooking in your kitchen, our Pure A2 Gir Cow Desi Ghee - Bilona Method remains the gold standard - its saturated fat structure is intrinsically resistant to oxidation in a way that even the best vegetable oils cannot match.

Label Traps: Terms That Sound Better Than They Are

The oil industry has responded to growing consumer awareness by creating labels that sound meaningful without making meaningful commitments. Watch out for these:

• "Natural" - has no regulated definition in the context of cooking oil. A fully refined, solvent-extracted oil can legally be labelled "natural."

• "Pure" - means undiluted (not mixed with another oil). It says nothing about the extraction method or degree of processing.

• "Light" or "Lite" - refers to flavour, not fat content or calories. Light olive oil, for example, is simply more refined than extra-virgin - it has a lighter flavour because its beneficial compounds have been partially removed.

• "Expeller-pressed" - means mechanically pressed without solvents, but does not specify temperature. Expeller-pressing at high speeds generates significant heat and does not guarantee the nutritional benefits of true cold-pressing.

• "Filtered" - describes a post-extraction clarification step that removes particulates. It neither confirms nor denies whether the oil was cold-pressed or refined.

• "Double-refined" or "extra-refined" - marketed as a quality claim, but simply means the oil has been refined twice, removing even more of its remaining natural content.

The only labels that carry genuine meaning are cold-pressed (with a temperature specification), wood-pressed or kachi ghani (specifying traditional wooden extraction), and unrefined (confirming no post-extraction chemical processing). When in doubt, look for oils with a visible colour, a characteristic smell, and a shorter shelf life - these are signs that something nutritionally real is still present.

Which Oil Should You Actually Buy?

The answer is straightforward once you know what the terms mean. For everyday Indian cooking, the hierarchy is clear:

• Best choice for high-heat cooking (frying, deep frying, bhuna): A2 Bilona Ghee or wood-pressed mustard oil - both have high smoke points and exceptional oxidative stability

• Best choice for everyday tadka, curries, and medium-heat cooking: Wood-pressed mustard oil or wood-pressed groundnut oil - both bring genuine nutritional value and characteristic flavours to Indian cuisine

• Best choice for raw use (salad dressings, finishing oil): Wood-pressed groundnut oil or wood-pressed sesame oil - their full flavour and antioxidant content shine when not heated

• What to remove from your kitchen: Refined sunflower, soybean, corn, and palm oil - particularly if they have been sitting in a clear plastic bottle under kitchen lights for weeks or months, which accelerates their already compromised oxidative state

Making the switch to wood-pressed oils is not complicated, expensive, or a lifestyle overhaul. It is simply choosing, at the moment of purchase, an oil that was made with care rather than efficiency - one that still contains what the seed always contained, rather than a processed remnant of it.

Explore our Wood-Pressed Groundnut Oil and Wood-Pressed Yellow Mustard Oil - both pressed the traditional way, with nothing added and nothing taken away.

The Bottom Line: Labels Should Mean Something

The language around cooking oil has been deliberately obscured by an industry that profits from confusion. When terms lose meaning, premium-sounding labels can be applied to mediocre products, and genuinely superior traditional methods get lost in the noise.

Wood-pressed means something precise and important - slow extraction, minimal heat, no chemicals, full nutritional integrity. It is the method that Indian kitchens relied on for generations before industrialisation replaced quality with cost efficiency. The oil that comes out of a kachi ghani is not the same product as what comes out of a hexane tank and a deodorisation column. One is food. The other is a processed fat that happens to be edible.

Choosing your cooking oil carefully is one of the most repeated decisions you make for your health. You use it every single day, across every cooked meal. That frequency means even a small difference in quality compounds into a very large difference in health outcome over years. Choose oils that were made with the same care your food deserves.