Durian smells the way it does because its aroma has at least two groups of volatile compound in it at the same time: sweet, fruity esters and pungent sulphur compounds that read as roasted onion, rotten cabbage and rotten egg. That two-group description comes from the 2017 genome paper and from a 2012 analysis of Thai Monthong durian, which found 44 odour-active compounds in the fruit. The genome paper also found that durian has four copies of MGL, a gene associated with making volatile sulphur compounds, where cacao has one.
Two families of compound, not one
The 2012 Monthong analysis found esters among the strongest odorants. Ethyl 2-methylbutanoate scored highest and was described as fruity, and ethyl butanoate and ethyl 2-methylpropanoate were also fruity. The sulphur compounds carried the other half: 1-(ethylsulfanyl)ethanethiol was described as roasted onion, hydrogen sulfide as rotten egg, methanethiol as rotten cabbage and ethanethiol as rotten onion.
The genome paper describes the same split: sulphur-containing volatiles “which may contribute to the distinct roasty, onion-like odor of durian”, and esters, “which may contribute to a sweeter, fruity odor”. We have not found a source comparing durian’s ester and sulphur load with other fruit, so we make no claim about how rare the combination is.
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 that the gene family for methionine gamma-lyase, MGL, had expanded in durian: four copies, against three in one cotton species, two in another and one in cacao. The paper says MGL “degrad[es] the sulfur-containing amino acids cysteine and methionine into methanethiol, which is further broken down into di- and trisulfides”. Two of the durian copies, called MGLb1 and MGLb2, were upregulated in the fruit compared with stem, root and leaf, with MGLb2 showing a 2,241-fold higher expression.
That is a genetic explanation for why durian fruit is equipped to make sulphur volatiles. The paper also reports that volatile sulphur compounds are produced during ripening.
The paper words the link carefully: MGL expansion is “associated with” volatile sulphur compound production. It is a genome and gene-expression study, not a sensory test, so it does not tell you how a particular fruit will smell at a stall 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. Humans detect odours with more than 400 olfactory receptors, and a 2019 study of 332 people found that genetic variation in a single receptor was frequently associated with changes in how intense an odorant seemed. That study did not test durian. It shows the general mechanism, which is why the same molecule can register as strong to one nose and weaker to another.
The second is that the fruit is not a fixed target. The genome paper reports that volatile sulphur compounds are produced during ripening, with MGL and the ripening-hormone gene ACS upregulated in the fruit alongside their downstream compounds. So the mixture changes as the fruit ripens. We have not found a source on how it shifts once a fruit is past its peak; for the practical side of that, see how to store durian.
Why the smell gets stronger after you open it
We have not found a published measurement of how much stronger durian smells once opened, so this section is reasoning rather than sourced fact. The likely reason is physical rather than chemical: the husk encloses the flesh, and once it is cracked open far more flesh is exposed to air, so the volatile compounds can escape much more easily than through an intact shell.
Why varieties smell different
The genome paper compared gene expression in the ripe flesh of three cultivars. It found sulphur metabolism, ethylene response and flavonoid pathways significantly more active in Musang King than in Monthong and Puang Manee, and says this “correlate[s] well with the stronger perceived taste and smell of the Musang King cultivar”. It also notes that pungent and bitter varieties are prized in Malaysia and Singapore, “whereas sweeter cultivars with a mild odor are popular in Thailand (for example, Monthong)”.
Beyond that, which varieties smell milder is poorly documented. FAMA’s standard for Musang King lists the aroma as strong (“aroma yang kuat”). Specialty Produce describes Red Prawn as having “a soft, floral, sweet scent, which is considered milder than other varieties”, while Golden Phoenix, despite a mild taste, is described by Specialty Produce as releasing “a pungent aroma with sweet, onion, and garlic-like undertones”, though one grower’s guide calls it a bit milder. RinggitPlus says D24’s “aroma is milder”. For most other named clones we have not found a source on how strongly they smell, so a sweet or mild taste is not a reliable guide to a mild smell. The variety reference gives the sources for each, and how to choose durian covers what the smell tells you at the stall.
How to actually cut the smell
We have not found published testing of any of these methods against durian smell, so treat what follows as common practical advice, not proven results.
In a car: crack the windows rather than sealing the fruit in a closed cabin. Activated charcoal or baking soda left in the car afterwards are the usual suggestions for what remains, and a wipe-down of any surface the flesh touched helps.
In a flat: ventilate first. Open windows and run a fan before anything else. Baking soda, activated charcoal and a small dish of ground coffee are the usual suggestions for absorbing what is left.
In the fridge: contain it before it spreads, rather than fighting it afterwards. Deshelled flesh wrapped tightly and sealed into an airtight container keeps the smell away from 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 a commonly shared tip in Singapore and Malaysia. We have not found a source confirming that the husk does anything chemically, and no published comparison shows husk water beats plain water and soap. It is harmless and free, and the part doing the work may simply be that you are washing your hands straight after eating.
The bans
Durian is not allowed on Singapore’s MRT. Mothership reports that SMRT began fining passengers S$500 for bringing durian onto its trains in 1988, with an MRT spokesperson citing the lingering odour in air-conditioned spaces, and that SBS Transit asks passengers not to bring items such as durians on its buses. Singapore Airlines states: “The carriage of durians in your cabin and/or checked baggage on our flight is also not allowed.” Hotels in Singapore have charged cleaning fees for durian in rooms, and the detail, with the sources, is in where you cannot take durian. We have not found a source covering other regional transport systems, hotels or airlines as a group.
Related
- Musang King, FAMA lists its aroma as strong
- Durian types and their D numbers
- Where you cannot take durian, the MRT, taxis, hotels and flights, and which of those bans actually carries a penalty
- How to store durian, including how to keep the smell out of your fridge
- How to choose durian at the stall
- Durian vs jackfruit, if you need the smell test in one line