Thonmai
Stand in front of the cooking oil shelf at any store in Chennai or Coimbatore and you will read the same three or four words over and over - wood-pressed, cold-pressed, refined, filtered - printed in confident lettering across every kind of bottle. The label design rarely tells you which one you are holding. A pale, odourless oil and a golden, sharp-smelling one can both call themselves natural. So it helps to know what each term is describing, because they are not describing the same thing.
Wood-pressed: the marachekku method
Wood-pressed oil comes from the marachekku, the traditional wooden rotary press still used in towns like Arani. Seeds or copra are loaded into a wooden mortar, and a heavy wooden pestle turns slowly, crushing them until the oil seeps out. The turning is unhurried, so the oil does not get overheated by fast machinery. What you are left with is the oil in more or less the state the seed carried it - its natural colour, its aroma, and its sediment, which is why unrefined wood-pressed oil often looks cloudy and settles at the bottom.
The term is descriptive, not a certification. It tells you about the pressing tool and the pace, not a laboratory grade. A genuinely wood-pressed groundnut oil smells distinctly of roasted groundnut; that smell is the honest signature of the method.
Cold-pressed: about temperature, not the press
Cold-pressed refers to keeping the temperature low during extraction so the oil is not damaged by heat. The confusion is that cold-pressed can be done with a modern steel expeller, a screw press, or a wooden press - the term is about heat control, not the machine. So there is real overlap: a slow wooden press that stays cool is, in effect, cold-pressed too. But a fast steel expeller run at low temperature also earns the label, and it will feel and smell different from marachekku oil.
Wood-pressed - names the wooden press and its slow speed.
Cold-pressed - names the low temperature, whatever the machine.
Refined - names the cleaning-up steps that come after pressing.
Refined: what happens after pressing
Refined oil starts as pressed oil, often extracted with high heat or chemical solvents to squeeze out the maximum from the seed, and is then put through several steps - degumming, neutralising, bleaching and deodorising - to strip out colour, smell and sediment. The result is a clear, near-flavourless oil with a high smoke point and a long shelf life, which is exactly why so much of India's frying oil is refined.
Refining is not a fault in itself; it serves a real purpose. But it does mean the oil no longer carries the aroma or the natural cloudiness of the seed. If a bottle is pale gold, perfectly clear and smells of almost nothing, it has very likely been refined, regardless of how the raw material was first pressed.
Reading a bottle honestly
Look past the front label to the fine print. Check whether the oil is described as unrefined or filtered rather than refined. Look at the oil itself if the packaging allows - our sesame and groundnut oils, for instance, carry the colour and settling you would expect from unrefined marachekku pressing. You can see how we describe each of ours on our products page, where the method is stated plainly rather than dressed up.
A last honest word. Wood-pressed and cold-pressed are descriptions of a process, not government-regulated grades in the way an FSSAI licence or an organic certification is. They tell you how the oil was likely made, and a truthful maker will happily explain the exact steps. So treat the terms as a starting question - ask how it was pressed, whether it was refined afterwards, and let the aroma and colour of the oil confirm the answer. That is closer to how our grandmothers judged oil at the mill than any word printed on a bottle.