Thonmai
In the early morning at our unit in Arani, before the road outside fills with traffic, the wooden chekku begins to turn. A heavy mortar carved from a single log, a pestle pressing down into a load of groundnuts, and the whole thing moving at a walking pace. You can put your hand near the fresh oil as it seeps out and feel that it is barely warm. That slowness is not nostalgia for its own sake. It is the reason the oil tastes and behaves the way it does.
Most oil sold in India today does not come from anything like this. It comes from a steel expeller, or from a solvent plant, machines built to move seed through in minutes rather than hours. We chose the older path deliberately, and it is worth explaining what actually differs between the two.
What a wooden chekku does differently
The word marachekku simply means wood-press. The seed or copra is crushed by a rotating wooden pestle inside a wooden mortar, driven slowly. Because the motion is gentle and unhurried, the temperature stays low - often in the range where the oil never gets hot enough to scorch. That matters because heat is what strips away aroma, colour, and some of the delicate compounds that give cold-pressed oils their character.
A modern expeller works on the opposite principle. It uses high pressure and rapid friction to squeeze out as much oil as possible, as fast as possible. The friction generates real heat, and the yield goes up. The trade-off is that the oil comes out hotter and often needs more filtering to look clean. It is efficient. It is just a different product.
Why we accept a lower yield
Wood-pressing gives us less oil per kilo of seed than an expeller would, and it takes far longer. On paper that is a bad business decision. We keep doing it because the character of the oil is the whole point of Thonmai. The groundnut oil keeps its nutty smell, the sesame keeps its deep colour, and the coconut oil carries the scent of the copra it came from.
Slower speed - the pestle turns at a pace that keeps friction, and therefore heat, low.
Lower yield - we get less oil per batch, which is a cost we absorb rather than pass on as thinner quality.
Minimal processing - the oil is settled and filtered, not refined, bleached, or deodorised.
Whole-seed sourcing - we buy groundnut, sesame, and copra directly rather than working from pre-processed cake.
Sourcing is part of the method
A good press cannot fix a poor raw material. Because so little happens to the oil after pressing, the seed itself has to be right. We source groundnut, sesame, and coconut close to home in the Tiruvannamalai region and check each lot before it goes into the chekku. Old or musty seed carries its flaws straight into the final oil, since there is no refining step to hide behind. You can read more about where our seed comes from and how we work on our about page.
What this means when you cook
In a Tamil kitchen these oils were never neutral background fat. Groundnut oil for a proper poriyal, sesame for pickles and for the first tempering of the day, coconut oil for a Kerala-leaning fish curry - each was chosen partly for its smell. Wood-pressed oil keeps that aromatic identity, which is exactly what a refined, deodorised oil is engineered to remove. If you have only cooked with refined oil, the first thing you notice is the smell coming off the pan.
A note on the word cold-pressed
We call our oils wood-pressed because that describes the machine and the method honestly. It is worth being clear that cold-pressed is a descriptive term, not a strict legal grade in India with a fixed temperature limit attached to it. What we can say plainly is that our process runs cool by design and involves no chemical extraction or refining. Beyond that, we would rather you judge the oil by how it smells and cooks than by any single label on the bottle.