What Is Chekku (Cold Pressed) Oil and Why Does It Matter?

Walk into any Tamil village fifty years ago and you would have heard a slow, creaking sound from the oil press – the chekku. A heavy wooden pestle turned inside a wooden mortar, crushing groundnuts or sesame seeds a few kilos at a time while a bull, and later a small motor, walked in circles. The oil that trickled out was golden, fragrant and alive.

How a chekku works

Seeds are first sun-dried and cleaned. They are loaded into the wooden mortar and the pestle rotates at a very low speed – roughly 10 to 15 rotations per minute. The friction is low, so the temperature inside the press stays below 45–50°C. Over 45 to 90 minutes the seeds are gradually crushed and the oil separates naturally. It is then allowed to settle and is filtered through cloth. Nothing else is done.

Why it matters

• Nutrients survive. Vitamin E, natural antioxidants like sesamol in gingelly oil, and the natural flavour compounds are heat sensitive. Low temperature pressing keeps them in the oil.
• No chemicals enter. Refined oils are typically extracted with hexane, then neutralised, bleached and deodorised at 200°C+. Chekku oil skips every one of these steps.
• Taste. You can smell roasted groundnut in kadalai ennai and the deep nuttiness of sesame in nallennai. That aroma is the oil telling you it has not been stripped.
• Small batches. A wooden press produces only a few litres an hour, so it is made close to where it is used, by people you can meet.

Chekku vs. “cold pressed” on a label

Many bottles say cold pressed but are made in high speed steel expellers that heat the oil to 80–100°C. True chekku oil comes from a wooden press. At Vaigai Oil Mills in K.Pudur, Madurai, our oils are pressed in wooden chekkus, and you are welcome to visit and watch.

The next time you open a bottle of chekku oil, notice the colour, the aroma and the small sediment at the bottom. Those are not flaws. They are the signature of an oil that has been made the slow way.