Sarson Ka Tel (Mustard Oil): Kachi Ghani, Erucic Acid and Argemone
Sarson ka tel (mustard oil) is the oil pressed from mustard seed, the golden, nose-prickling cooking fat of Punjab, Bengal, Bihar and most of northern Pakistan. It is also the only common kitchen oil that is banned for cooking in America, has a special legal ceiling in Europe, and once killed about sixty people in Delhi in a single summer. None of those three facts means what WhatsApp says it means, and this page explains each one calmly: what “kachi ghani” really promises, what erucic acid is, and the argemone adulteration that is the one real danger.
The short version
- English name: mustard oil; Unani roghan-e-sarson
- Local names: sarson ka tel, sarso ka tel, kachi ghani (first cold press), kolhu ka tel (bullock or wooden press oil)
- Plant sources: Brassica juncea (rai), Brassica nigra and Brassica campestris (sarson)
- Why it bites: allyl isothiocyanate, the same compound that makes wasabi and horseradish sting
- Real danger: argemone (satyanashi) seed oil mixed into loose oil, which causes epidemic dropsy
- Regulatory note: not sold as a food oil in the US because of erucic acid; the EU allows it with a higher limit than other oils
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What is kachi ghani, and how does it differ from refined or kolhu oil?
Kachi ghani means “raw press”. The seed is crushed at low temperature in one pass, the oil is filtered, and that is the product. Nothing is bleached, deodorised or heated to extraction temperature, so the oil keeps its colour, its cloud of fine sediment and, above all, its pungency. That pungency is allyl isothiocyanate, formed when the seed is crushed and an enzyme meets a sulphur compound (sinigrin). A refined mustard oil has been through solvent or high-heat extraction and then refining, which strips most of that sharpness along with the colour. It is a milder, paler, more neutral oil, and it is not what grandmothers mean by sarson ka tel.
Kolhu ka tel is the village version: a wooden or stone press, once bullock-turned, now motorised, and also a slow cold press. The difference from factory kachi ghani is hygiene and testing, not chemistry: a kolhu sells loose oil in your own bottle, a brand sells it sealed and dated. That difference is the whole safety story below.
Expeller oil sits in between: a steel screw press that runs warm from friction, less pungent than kachi ghani but not refined. For the seeds themselves, see mustard seeds and tempering.
Why does mustard oil sting your eyes, and should you heat it till it smokes?
Allyl isothiocyanate is volatile. When the oil heats, it leaves the pan as vapour, hits your eyes and nose, and the oil in the pan loses its bite. That is the whole reason for the old habit of heating sarson ka tel “till it smokes” before adding anything: the cook is driving off the pungency so the dish tastes nutty rather than sharp.
The trouble is that smoke means the oil has passed its smoke point and is breaking down into acrolein and other irritants. Mustard oil’s smoke point is commonly quoted at around 250 °C, high for a cold-pressed oil, so it fries well; you do not need to go past it to tame the flavour.
The step most recipes get wrong: shimmer, not smoke
Heat the oil on medium until the surface ripples and a test mustard seed or a shred of onion sizzles at once. That is well above the point where most of the pungency has gone and well below the smoke point. Take it further and you are breathing oil-breakdown fumes for a slightly nuttier taste, which is a poor trade. If you want the pungency gone completely, heat to shimmering, add the tarka, and let the first thirty seconds of frying finish the job. The old “smoke it first” habit comes from the days of thick, very pungent kolhu oil; a modern kachi ghani needs far less.
How is sarson ka tel made, and why does the loose kind go bitter?
Dried seed is cleaned, pressed, left to settle, filtered and bottled; the cake (khal) goes to cattle. A cold press yields roughly a third of the seed weight as oil, which is why “mustard oil” at the price of refined palm oil should make you suspicious. Fresh oil is deep yellow with a sharp, clean smell. Over months it turns bitter and the bite fades, because the isothiocyanate evaporates and the polyunsaturated fats oxidise, faster in light and heat.
The storage step nobody mentions: keep it in the dark, away from the stove
A clear plastic jerrycan on the counter next to the burner is the worst possible home for kachi ghani. Light and heat together strip the pungency in weeks and bring on rancidity in a few months. Decant into a steel or dark glass container with a tight lid, keep it in a cupboard, and buy quantities you will use within three or four months of the pack date. A cold-pressed oil kept that way still smells like itself at the bottom of the bottle. If it smells of paint or old nuts, it is rancid; use it for a lamp or a door hinge, not a daal.
Argemone (satyanashi): the one adulteration that has killed people
Argemone mexicana is the yellow-flowered prickly poppy (satyanashi, bharband, pili kateli) that grows wild along mustard fields. Its seeds look like mustard seeds and its oil is cheap, so it has been mixed into loose mustard oil for a century. Argemone oil carries two alkaloids, sanguinarine and dihydrosanguinarine, which damage small blood vessels and the heart.
The result is epidemic dropsy. In August 1998 Delhi had its worst outbreak: adulterated loose oil sold from Uttam Nagar and neighbouring areas sent hundreds of people to hospital within weeks; medical reviews put the final toll at around sixty deaths and about three thousand people affected. The Delhi government banned the sale of loose mustard oil, courts ordered minimum sealed packs, and the packing date became mandatory on labels. Smaller outbreaks have been reported from other Indian states since.
Several people who eat from the same kitchen develop sudden swelling of both legs and feet (pitting oedema), often with diarrhoea and vomiting first, then breathlessness on walking or lying flat, a racing heart, red or blurred eyes, or unusual tiredness over days to a couple of weeks. Epidemic dropsy affects the whole household because everyone ate the same oil, and that pattern is the clue a doctor needs. Bring the oil, in its container, to the hospital so it can be tested. Children and pregnant women are hit hardest. Breathlessness with leg swelling is an emergency, not a wait-and-see.
The honest test: the nitric-acid check is a lab test, so your only home defence is the seal
Every “detect fake mustard oil at home” video repeats the nitric acid test: mix equal parts oil and concentrated nitric acid and watch for an orange to red colour, which is sanguinarine reacting. The test is real and India’s food regulator lists it. It is also useless in a kitchen, because concentrated nitric acid is a corrosive laboratory reagent that no household should keep, and the fridge, water or paper tests online show nothing about argemone at all. The only protective step a buyer controls is where the oil comes from. The 1998 adulteration entered at the loose-oil stage, in drums and repacked tins, which is exactly why Delhi banned loose sale. Buy sealed, branded oil with a batch number and packing date, from a shop that sells enough to turn stock over, and skip khula tel from a drum however much better it smells. Our general checks for loose cooking oil and fake olive oil cover the mineral-oil and mixing tricks that also plague loose sale.
Erucic acid: why the US bans it for cooking, and what that does and does not mean
Erucic acid is a long-chain fatty acid that makes up a large share of traditional mustard oil; the US Food and Drug Administration’s import alert puts it at 20 to 40 per cent. Decades ago, feeding studies in rats and piglets on very high erucic-acid diets produced fat deposits in heart muscle (myocardial lipidosis), which reversed when the diet stopped. On that basis the FDA classes expressed mustard oil as an unapproved food additive, so bottles sold in America must carry “for external use only”, and shipments meant for cooking can be detained. The same concern is why canola was bred from rapeseed to contain almost no erucic acid.
Europe took a different route. The European Food Safety Authority set a tolerable daily intake of 7 mg of erucic acid per kilogram of body weight in 2016, noting that average diets stayed under it and only high-consuming small children approached it. The EU then set legal maximums: 20 g per kg for ordinary vegetable oils, but a higher ceiling of 50 g per kg specifically for mustard oil, camelina oil and borage oil, because those oils naturally carry more. In India, mustard oil is a standard food oil with its own quality rules, and in 2020 to 2021 the regulator banned blending it with other oils, partly to stop cheap palm oil being sold as mustard.
The fair reading: the heart finding is from animals on extreme diets, and a 2023 review says plainly that it has not been shown in humans. The caution worth keeping is not to make it the only fat in a small child’s diet, and not to drink it by the spoon as a “tonic”, which concentrates whatever risk there is for no benefit. For which oil to lean on if cholesterol is your concern, see our cooking oil ranking for cholesterol in Pakistan.
Hair, skin and joints: the uses that other pages own
Sarson ka tel is the winter massage oil of the north. The honest summary: it warms the skin, improves local blood flow and traps moisture, and that is the whole mechanism; it does not regrow hair or repair a joint. Sensitive skin can react to the isothiocyanate, so patch test on the inner forearm for 24 hours first, and never put oil in a child’s nose or ear. The scalp routine is on mustard oil champi, the comparison on coconut, sesame and mustard oil for hair, and the joint rub on best oil for knee pain massage.
Bottom line
Known: kachi ghani is cold-pressed oil whose bite is allyl isothiocyanate, which fades with heat, light and age; erucic acid is why America bans it for cooking and Europe caps it, on animal evidence never confirmed in people. Tradition claims: it warms, protects and strengthens. Uncertain: whether its fat profile is better or worse than other common oils over a lifetime. The one safety issue that is not uncertain is argemone in loose oil, and the defence is boring: a sealed, dated, branded bottle, stored in the dark, heated to a shimmer and not to smoke. More kitchen chemistry in our Kitchen Science series.
Sarson ka tel questions, answered
Sarson ka tel in English kya hai?
Mustard oil. In Unani texts it is roghan-e-sarson, and the Arabic is duhn al-khardal. “Kachi ghani” on a label is the cold-pressed, unrefined grade.
Kachi ghani mustard oil kya hota hai, aur refined se kya farq hai?
Kachi ghani is seed crushed cold in one pass and filtered, so it keeps its colour, sediment and pungency. Refined mustard oil has been extracted with heat or solvent and then bleached and deodorised, so it is paler, milder and closer to a neutral oil. Both are mustard oil; only kachi ghani tastes like it.
Sarson ka tel khane ke fayde aur nuksan kya hain?
It is a flavourful cooking fat with a high smoke point and mostly unsaturated fats that has fed northern South Asia for centuries. The harms are specific: argemone in loose oil, rancidity in badly stored oil, skin irritation in sensitive people, and the unresolved erucic-acid question. It is not a tonic to drink by the spoon.
Is mustard oil banned in America and Europe for cooking?
In the US, yes: the FDA does not permit expressed mustard oil as a food oil because of its erucic acid, so bottles say “for external use only”. In the EU it is legal with a maximum erucic-acid level of 50 g per kg, higher than the 20 g per kg allowed for other oils. In Pakistan and India it is an ordinary food oil.
How do I know if my mustard oil is adulterated with argemone (satyanashi)?
You cannot tell by look, smell or any kitchen trick. The nitric acid colour test works but needs concentrated acid, which is a laboratory reagent. Your protection is the source: sealed, branded, batch-numbered oil rather than loose oil from a drum, which is where argemone enters. If a household develops leg swelling and diarrhoea together, stop the oil and see a doctor with the bottle.
Why does mustard oil make my eyes sting when heating?
Allyl isothiocyanate, the pungent compound in the oil, boils off as vapour when heated and irritates eyes and nose exactly as cut onions do. The sting fades as the compound leaves the pan, which is why heated mustard oil tastes nutty rather than sharp.
What is the smoke point of mustard oil for frying?
Around 250 °C is the commonly quoted figure, which is high and makes it suitable for deep and shallow frying. Heating it until it visibly smokes, as many recipes say, takes it past that point and produces harsh fumes; heating to a shimmer is enough to tame the pungency.
Sarson ka tel kaise banta hai (kolhu vs expeller)?
Kolhu oil comes from a slow wooden or stone press, traditionally bullock-driven, now motorised, and is sold loose. Expeller oil comes from a steel screw press that runs warm from friction. Factory kachi ghani is a cold press with filtering, sealing and dating. Chemically kolhu and kachi ghani are close; the difference is testing and packaging.
How long does sarson ka tel keep, and why does it go bitter?
Three to four months from packing if kept in a dark, cool cupboard in steel or dark glass; much less in a clear container by the stove. Bitterness and a paint-like smell mean the polyunsaturated fats have oxidised. The pungency fades first, then rancidity follows.
Can we use kachi ghani mustard oil for hair?
Yes, it is the traditional champi oil, warmed and rubbed into the scalp then washed out. It conditions and improves the feel of hair; it does not regrow hair. Patch test first, because the pungent compound irritates some scalps. Our mustard oil champi page has the routine.
Sources
- US FDA Import Alert 26-04: Detention without physical examination of expressed mustard oil (erucic acid 20 to 40 per cent)
- Erucic acid, both sides of the story: a concise review. Molecules, 2023 (EFSA TDI 7 mg/kg bw; cardiac effects not confirmed in humans)
- Commission Regulation (EU) 2019/1870: maximum levels of erucic acid (20 g/kg vegetable oils; 50 g/kg mustard, camelina and borage oil)
- Sharma BD et al. Epidemic dropsy: observations on pathophysiology and clinical features during the Delhi epidemic of 1998. Tropical Doctor, 2002
- The Tribune, 27 August 1998: Delhi dropsy outbreak, ban on loose mustard oil
- 1998 Delhi oil poisoning (toll figures citing The Lancet 1998 and Forensic Science International 2001)