What Is the Smoke Point of Mustard Oil?

Published research puts the smoke point of mustard oil at 250°C, but it is better to refer to a range. Measured smoke points across common cooking oils run from about 175°C to 268°C, and a single oil shifts by 40 degrees or more depending on how much free fatty acid it carries.

Measured values and tabulated ones are not interchangeable, and that difference matters more than the figure itself. Smoke point is also a weak guide to whether an oil fries well, which is the part most smoke point pages leave out.

Where does the 250°C smoke point figure come from?

A 2025 review of mustard (Brassica juncea) in Frontiers in Nutrition reports a smoke point of 250°C for mustard seed oil. That is the figure most reference tables carry. It is a category value, not a measurement separated by pressing method or refinement grade, so it is not a guaranteed floor for any bottle.

Why do published smoke point figures for the same oil disagree?

Published smoke point figures disagree because smoke point is a measured behaviour, not a constant. The standard test is AOCS Official Method Cc 9a-48, the Cleveland Open Cup, in which oil is heated until a continuous bluish smoke appears. A 2025 study in Foods notes that this endpoint "relies on visual assessment, which is subjective".

Composition drives the number, and free fatty acid concentration drives it hardest. The American Oil Chemists' Society puts smoke point above 220°C when free fatty acids stay under 0.05%, and visible smoke at about 180°C once they reach 0.3-0.4%. A 40 degree swing from one variable.

The same was determined by the Foods study: across 48 virgin olive oils, free fatty acid content carried the greatest regression coefficient, and a model based on it alone predicted smoke point with an R² of 0.88.

How does mustard oil compare with ghee, groundnut, coconut and olive oil?

Numbers that can be directly compared are less common than the charts imply. The table separates figures measured in one accredited laboratory run from figures reported in review literature, because the two are not interchangeable.

The measured rows come from one 2018 study of ten supermarket oils, run in an ISO 17025 accredited laboratory by Modern Olives Laboratory Services. That is an olive oil laboratory, so its framing favours olive oil, though the method is standard.

Does kachi ghani or cold pressed mustard oil smoke lower than refined?

In principle yes, though no published side by side measurement of kachi ghani and refined mustard oil under one method could be located. AOCS describes alkali refining converting free fatty acids into soaps that are centrifuged out, and physical refining removing them by distillation during deodorisation.

Because they bypass those processes by design, cold-pressed or wood-pressed oils retain more of what refining strips, free fatty acids included. Assume a smoke point below the tabulated 250°C.

What happens to an oil's smoke point when you reuse it?

An oil's smoke point falls with reuse, because frying hydrolyses fat into free fatty acids and those are the strongest single predictor of smoke point.

In the 2018 trials, free fatty acids rose in most oils after 360 minutes at 180°C, and polar compounds climbed: sunflower 21.75%, grapeseed 20.24%, canola 17.32%, rice bran 15.66%, against 10.5% for extra virgin olive oil and 9.68% for coconut oil. Many regulators treat 24 to 27% polar compounds as the ceiling for frying oil.

The ICMR-National Institute of Nutrition is blunt about the household version. Its 2024 Dietary Guidelines say repeated heating generates harmful oxidative (polar) compounds and must be avoided, and advise that once-used frying oil be filtered into a curry rather than fried in again, then finished within a day or two.

Indian cooking heats mustard oil until it smokes. Is that a mistake?

Heating mustard oil to smoking point is not a mistake, and it is worth saying so rather than scolding a practice older than the measurements. Taking mustard oil to smoking point before adding the tadka is customary across the kitchens of northern and eastern India, and it reduces the sharpness of fresh oil. Briefly touching smoke point is a different event from holding oil there for an hour.

The real cost sits in what happens next. The 2025 mustard review notes that repeated frying of mustard seed oil, at 180°C for ten minutes three times over, generates lipid peroxidation products. The technique is not the problem. Reusing that smoked oil across several sessions is.

Which mustard oil suits which kind of heat?

Composition matters more here than the smoke point figure, and it is the one thing a buyer can check. SatRas publishes per 100 g values for its three cold pressed mustard oils, and they are genuinely different oils.

What did the oxidative stability testing show?

Composition matters to heat, and the 2018 trials show why. Oils higher in monounsaturated fat held oxidative stability longer than polyunsaturated ones. Refined high oleic groundnut oil recorded a 35.37 hour induction time at 110°C against 6.10 hours for sunflower oil.

That is a pattern across oils, not a measurement of any mustard oil, and no equivalent testing on these three has been published.

The yellow oil at 72.6 g MUFA and 4.9 g saturated fat is the mildest and the usual starting point for anyone switching from a refined oil. The black oil, rich in allyl isothiocyanate, is the pungent one for tadka, marination and pickling.

The high oleic oil, from the Raya Hisar 1706 seed developed by CCSHAU, is the only one with a published fatty acid report behind it. Pressing and storage questions are answered on the SatRas FAQ page.

Does a high smoke point mean an oil is safe to cook with?

By itself, it does not, and this is the message many information pages ignore. The 2018 study concluded that under its conditions smoke point did not predict oil performance when heated, and that oxidative stability and UV coefficients combined with total polyunsaturated fat were better predictors.

Grapeseed oil recorded the highest smoke point of the ten tested at 268.0°C and was among the worst on degradation, at 20.24% polar compounds after six hours.

Smoke point also says nothing about what people are usually asking underneath it: erucic acid, which the 2025 review reports exceeds 30% of total fatty acids in commercially cultivated mustard species and against which SatRas publishes 23.85 g per 100 g for its high oleic oil, or adulteration, storage age and contaminant load.

This article is educational and is not medical advice. For dietary guidance specific to you, consult a qualified professional.

Frequently asked questions

What is the boiling point or burning point of mustard oil?

Cooking oils have no useful boiling point, because triglycerides break down before they boil. The measurements that exist are smoke, flash and fire points, all defined under AOCS Official Method Cc 9a-48, and burning point corresponds to fire point. No published fire point measurement for mustard oil could be located, so none is quoted here.

Is mustard oil's smoke point higher than olive oil's?

On published figures, yes. Mustard seed oil is reported at 250°C in review literature, while extra virgin olive oil measured 206.7°C and virgin olive oil 175.3°C in accredited laboratory testing. The comparison is imperfect, because the mustard figure is a tabulated value and the olive figures are direct measurements.

Do black and yellow mustard oil have different smoke points?

No separately measured smoke points for black and yellow mustard oil have been published that we could find. Their fat compositions do differ, and composition influences thermal behaviour, so assuming an identical smoke point for both is an assumption rather than a measured fact.

What is the smoke point of wood pressed mustard oil?

No published measurement exists for wood pressed mustard oil specifically. Since wood pressing skips the refining steps that strip free fatty acids, and free fatty acid content is the strongest predictor of smoke point, a wood pressed oil should be expected to smoke below the 250°C figure quoted for mustard oil generally.

Is ghee or mustard oil better for deep frying?

Both are reported at around 250°C, so smoke point does not separate them. Ghee is far higher in saturated fat, which resists oxidation, while mustard oil is higher in unsaturated fat. Neither should be reused repeatedly, which matters more for deep frying than either starting figure.