Why Does Durian Smell So Strong? The Actual Chemistry

Two families of aroma compound at once, not one, and a 2017 genome study explains why durian is so well built to make the sulphurous half.

Durian smells the way it does because its flesh carries two very different families of aroma compound at the same time: sweet, fruity esters and pungent, sulphur-based volatiles that read as onion, gas or cooked egg. Most fruit leans towards one side or the other. Durian does both at once, which is why the same fruit can smell like dessert and drain in the same breath. A 2017 genome study found durian’s DNA carries an unusually expanded set of genes for making exactly that kind of sulphur compound, switched on hard in the fruit itself.

Two families of compound, not one

Esters, the class of molecule behind the smell of banana, pineapple and pear, give durian’s aroma its sweet, fruity edge. Volatile sulphur compounds give it the other half: onion, garlic, cooked cabbage, gas, and at the sharper end, something close to rotten egg.

Almost no other commonly eaten fruit carries a serious amount of both families at once. Most fruit sits almost entirely in the ester camp, which is why it smells straightforwardly sweet. Durian’s sulphur load is what sets it apart, and the balance between the two is what makes one variety read as milder and another as considerably stronger.

What the 2017 genome study actually found

The most solid published science behind durian’s smell is a genome paper, not a flavour study:

Teh, B.T. et al. (2017). “The draft genome of tropical fruit durian (Durio zibethinus).” Nature Genetics, 49(11), pages 1633 to 1641.

The team sequenced the genome of a Musang King durian tree and compared its gene content against other plants. They found the gene family for methionine gamma-lyase, MGL, an enzyme that breaks down the amino acid methionine into volatile sulphur compounds, had expanded in durian: more copies than in related species. Those extra copies were also strongly upregulated, switched on harder, specifically in the fruit rather than in the leaf or other tissue.

That is a genuinely useful finding: a genetic explanation for why durian fruit is so well equipped to manufacture sulphur volatiles at all.

It is worth being precise about what the paper did not do. It did not measure the actual smell coming off a fruit, did not compare sulphur output across different durian varieties, and did not run an experiment proving MGL activity produces the specific compounds you smell at a stall. It is a genome and gene-expression study on one tree of one variety, explaining why the biological machinery for the smell exists, not mapping every molecule in the aroma or why two people at the same stall react so differently.

Why people disagree so strongly

Two things stack on top of each other, and either alone would start an argument.

The first is perception. Smell relies on receptor genes that vary from person to person, so the same molecule can register as strong and unpleasant to one nose and barely noticeable to another. That is a general feature of human smell, not something unique to durian.

The second is that the fruit is not a fixed target. Ripeness moves the mixture. As durian passes its peak and starts to ferment, the balance shifts further towards sulphurous and alcohol-like notes, the same shift that turns good flesh sour and boozy-edged if it sits too long (see how to store durian). Two durians from the same tree, eaten a day apart, are not giving off an identical mixture to begin with.

Why the smell gets stronger after you open it

A whole, unopened durian smells far less than the same fruit five minutes after it is cracked open, and the reason is mostly physical rather than chemical. The husk is a sealed container. Once it is opened, the surface area of flesh exposed to air increases enormously, and the volatile compounds escape far faster than they could through an intact shell.

The smell then keeps building the longer the opened fruit sits out, for much the same reason a cut onion gets stronger on a counter rather than weaker: continued exposure to air, plus continued ripening, keeps releasing more of the mixture rather than using it up. That is also why a durian left out too long smells harsher than the same fruit eaten within the hour.

Why varieties smell different

If the ratio of esters to sulphur compounds is what defines durian’s smell, a variety that leans further towards esters will read as sweeter and less sharp, and one carrying more sulphur compounds will read as stronger and more savoury.

Musang King is intense and assertive without being the single strongest smell on a stall, consistent with its heavy, bittersweet flavour. Milder clones are generally sweeter and less pungent, which is why two people can each insist a different durian is “not that bad” while disagreeing about which one. Picking a gentler variety matters here as much as how to choose durian does at the point of sale. The variety reference covers how each named clone compares.

How to actually cut the smell

None of this removes the smell entirely, but each cuts how far it travels and how long it lingers, and some work better than others.

In a car: crack the windows rather than sealing the fruit in a hot, closed cabin, since heat speeds up how fast volatiles escape. Activated charcoal or baking soda left in the car afterwards absorbs some of what remains, and a wipe-down of any surface the flesh touched helps.

In a flat: ventilate first, mask second. Open windows and run a fan before anything else. Baking soda, activated charcoal and a small dish of ground coffee genuinely absorb odour molecules rather than covering them up, more than most air fresheners manage.

In the fridge: contain it before it spreads, rather than fighting it afterwards. Deshelled flesh wrapped tightly and sealed into an airtight container, glass rather than plastic where you have the choice, keeps the smell out of your milk and butter. Full method in how to store durian.

On your hands: pouring water into the emptied husk, swirling it, and washing your hands in that water is standard practice across Singapore and Malaysia. Whether the husk itself does anything chemically is not established, and no published comparison confirms husk water beats plain water and soap. It is harmless and free, and the part doing the actual work may simply be that you are washing your hands straight after eating, whatever the water passed through first.

The bans

Durian is not allowed on Singapore’s MRT, LRT or public buses, and similar rules apply on several transport systems in the region. Many hotels across Southeast Asia refuse to let guests bring it into rooms, and several regional airlines exclude it from cabin baggage and hold luggage alike. None of this is superstition. It is a strong, lingering smell in an enclosed space, and operators have made a straightforward call that most travellers would rather not share it.

Facts on this page were last checked on . Health information here is general and is not medical advice. Spotted an error? Tell us and we will check it.
All durian guides