Ghee left over from deep frying can be strained and used once more in a curry or dal within a day or two, but it should not be used for frying again. That is ICMR-NIN's and FSSAI's household advice for used frying oil; neither names ghee or makes an exception for it.
The question comes up in every kitchen that fries puris, pakoras or sweets in ghee. A kadhai of ghee is not cheap, and throwing it out after one batch feels wasteful. Here is what happens to the fat while you fry, what the Indian guidance says, and how to judge what is left in the pan.
At a glance
- ICMR-NIN (2024) and FSSAI both say fat used for frying at home should be filtered, used in a curry within a day or two, and not used for frying again; neither names ghee or exempts it.
- FSSAI's 25 per cent total polar compounds limit is written for vegetable oil in food businesses; its catering guidance allows at most three uses and calls one ideal.
- Frying breaks fat down by hydrolysis, oxidation and polymerisation; a 2022 Iranian study found acid value and polar compounds rose fastest in ghee among four fats.
- A 2016 Delhi study found clarified butter gained between about 2.6 and 6 g of trans fat per 100 g when heated at 180 °C and 220 °C.
- Discard used ghee that is dark and murky, foams, smokes blue-grey or has changed consistency, and never pour it down the drain.
What happens to ghee when you fry in it?
Frying changes a fat through three kinds of reaction: hydrolysis, oxidation and polymerisation. Hydrolysis splits the fat's triglycerides and releases free fatty acids, while oxidation and polymerisation build up breakdown products and larger linked molecules. The one study we found that measured these changes in ghee saw both markers rise.
Hydrolysis shows up as a rising acid value, which is a measure of free fatty acids. Oxidation and polymerisation show up as a rise in total polar compounds, a single figure that groups together the oxidised, broken-down and polymerised material that builds up in frying fat. FSSAI uses that figure as the test for when a frying oil has had its day.
Heat changes other things too. A 2016 laboratory study from Delhi heated six fats used in Indian kitchens, including clarified butter, at 180°C and 220°C. All six gained trans fatty acids and saturated fatty acids and lost cis-unsaturated fatty acids. In the two fats, as distinct from the oils (clarified butter and partially hydrogenated vegetable oil), trans fat rose by between about 2.6 and 6 g per 100 g. The authors found no significant difference between plain heating and frying.
Does FSSAI's 25 per cent limit apply to ghee?
Not by name. The FSSAI rule says vegetable oil that has developed more than 25 per cent total polar compounds shall not be used. It sits in the licensing regulations for food businesses, not home kitchens, and it does not mention ghee or any animal fat.
The same section of the regulations, as FSSAI's guidance note on used cooking oil sets it out, also tells caterers and food service businesses:
- reuse of cooking oil should be avoided;
- if oil is reheated, use it a maximum of three times, and once is ideal;
- reheating and reuse should be avoided as far as possible, and leftover oil avoided wherever possible.
Those three lines say "cooking oil" or "oil" rather than "vegetable oil", but they too are written for businesses. So the honest answer is that no FSSAI rule we found names ghee. The chemistry does not stop at the label, though, and the one study we found that measured polar compounds in ghee saw it cross that 25 per cent line.
What does ICMR-NIN advise about reusing frying fat?
ICMR-NIN's Dietary Guidelines for Indians (2024) say vegetable oil once used for frying at home should be filtered and may be used for curry preparation, but using it for frying again should be avoided. Such oil should be eaten within a day or two and not stored for long, because used oil deteriorates quickly.
The guidelines go further in other places. They say repeated heating of cooking oils generates harmful oxidative (polar) compounds and must be avoided. In the section on cooking methods they add that used oil should not be mixed with fresh oil and reused, and elsewhere they advise avoiding reheating and reuse of left-over heated oils.
Like FSSAI, ICMR-NIN writes this advice about oil. Its paragraph on repeated heating does say "vegetable oils/fat", and the same guidelines ask readers to limit ghee in the first place. Nothing in them suggests ghee should be treated differently once it has been through a fryer.
FSSAI's household advice in its guidance note on used cooking oil is almost word for word the same: filter oil once used for frying, use it for curry, avoid frying in it again, and use it up within a day or two.
What do studies on ghee and frying actually show?
Few studies have tested ghee directly, and the two we found point in different directions. Both are small laboratory studies, neither was done on Indian bilona ghee, and neither settles the question for a home kitchen. They are useful mainly for showing that ghee is not immune to frying damage.
The first, a 2022 study from Zanjan University of Medical Sciences in Iran, heated three vegetable oils and one ghee bought from a traditional dairy retailer, then fried chicken and potato in them. Acid value and total polar compounds rose fastest in the ghee. Even before heating, that ghee sample read 15 per cent total polar compounds on the portable meter the team used. With food in the pan, none of the four fats was fit for a second frying by the study's cut-offs of 1 per cent acid value and 25 per cent polar compounds.
The second, a 2018 Raman spectroscopy study from Pakistan, looked at desi ghee heated at different temperatures, for different lengths of time and when reused. It reported that the ghee could be reused if heated below 180°C, and heated for up to 30 minutes without appreciable molecular change, provided the heating was controlled. It measured spectral changes, not polar compounds or acid value, so it does not tell you whether the fat would pass the FSSAI test.
The two studies used different ghee, different heating and different measurements, so they cannot be set against each other directly. Neither overturns the official advice. Our article on ghee's smoke point and when it matters covers why frying is also where a good ghee's aroma is lost.
How can you tell what has changed in used ghee?
Most of the chemical change in frying fat cannot be seen. Free fatty acids, polar compounds and trans fats are measured with laboratory methods or a meter, not by eye. What you can see are the later signs FSSAI lists: a dark and murky colour, tough foam, blue-grey smoke and a change in consistency.
| What changes with heating and reuse | How you can tell | Source |
|---|---|---|
| Hydrolysis raises free fatty acids | Not visible; measured as acid value | Mohammadian Fazli et al., 2022 |
| Oxidation and polymerisation raise total polar compounds | Not visible; measured in a laboratory or with a frying oil meter | Mohammadian Fazli et al., 2022; FSSAI |
| Trans and saturated fatty acids rise, cis-unsaturated fall | Not visible; measured by gas chromatography | Bhardwaj et al., 2016 |
| Colour | Fat turns dark and murky | FSSAI |
| Foaming | Tough foam forms | FSSAI |
| Smoke | Blue-grey smoke appears | FSSAI |
| Texture | The consistency of the fat changes | FSSAI |
The limits that regulators set, on polar compounds and acid value, are on the rows you cannot see. Looking fine is not proof that the fat is fine.
How should you strain, store and use leftover ghee?
Let it cool, strain out every particle of food, keep it in its own clean container away from your fresh ghee, and use it within a day or two for a curry, dal or sabzi rather than for frying. If it shows any of the warning signs, throw it away instead.
- Let it cool first. FSSAI's note advises against transferring hot oil, to avoid spills and injury. Wait until the ghee is warm, not hot.
- Strain it. Pour it through a fine steel strainer or muslin to remove crumbs and batter. FSSAI advises filtering frying oil to remove food particles.
- Keep it separate. Use a clean, dry container just for used ghee. Do not pour it back into your fresh jar; FSSAI says not to refill the fresh oil container with used oil, and ICMR-NIN says not to mix used and fresh oil.
- Close it and keep it cool. In the Iranian study, heated fats kept best in closed containers at refrigerator temperature. Our guide to how to store ghee and how long it lasts covers why air, light and moisture matter.
- Use it within a day or two, for cooking, not frying. Both ICMR-NIN and FSSAI suggest using it in curry preparation, and both say not to store used oil for long.
- Judge it before you use it. If it has turned dark and murky, foams, smokes blue-grey or has changed consistency, discard it.
When should you throw used ghee away?
Throw it away when it shows any of FSSAI's signs: a dark and murky colour, tough foam, blue-grey smoke or a changed consistency. Also discard it if it has been sitting for more than a day or two since you fried in it, because both ICMR-NIN and FSSAI say used oil should not be stored for long.
Disposal matters too. FSSAI asks households not to pour used cooking oil into drains, because it blocks sewers. For small amounts, mix it with something absorbent, such as sand, sawdust, paper towel or food scraps, and put it in the dustbin.
The simpler habit is to deep fry in ghee less often, and keep good ghee, Himdhara's or anyone else's, for the places where you can taste it.
The short version
Ghee left over from deep frying can be strained and used once in a curry or dal within a day or two, but not for frying again. That is what ICMR-NIN and FSSAI advise for frying oil at home, and neither names ghee or makes an exception for it. FSSAI's 25 per cent polar compound limit is written for vegetable oil in food businesses and does not name ghee, but the one study we found that measured ghee saw it break down faster than three vegetable oils. Discard used ghee that is dark, foamy, smoking blue-grey or changed in texture.
Sources
Further reading behind the figures above. Himdhara's own numbers — yields, batch results — come from our production records and the batch reports on the lab reports page.
- ICMR-National Institute of Nutrition (2024). Dietary Guidelines for Indians. ICMR-NIN, Hyderabad.
- Food Safety and Standards Authority of India (2018). Handling and Disposal of Used Cooking Oil (Guidance Note No. 06/2018). FSSAI.
- Mohammadian Fazli M., Zanganeh H., Hassanzadazar H. (2022). Effect of heating on disposal point of main edible oils available in Iran market. Food Science & Nutrition.
- Bhardwaj S. et al. (2016). Effect of heating/reheating of fats/oils, as used by Asian Indians, on trans fatty acid formation. Food Chemistry.
- Ahmad N. et al. (2018). Heating Effects of Desi Ghee Using Raman Spectroscopy. Applied Spectroscopy.