Reference point
Lightly squeeze the peel of a ripe yellow kumquat.
Do this before you read on. An entry only works when you have just smelled the thing.
Much sweeter than lime, round, without any edge. At the end of the breath a faint, almost floral note appears, brief and blurred — something lime and pomelo peel don’t have.
Beginners often call it a sweet shop smell, and they are not wrong. Many citrus sweets and soft drinks borrow exactly this round sweetness, so your memory has met it hundreds of times before you meet the real fruit.
Green and ripe kumquats smell different. The green fruit is sharper, closer to lime, with almost no floral part. Only the ripe yellow fruit is sweet and round enough. This is an entry where the moment of picking matters more than the variety.
How to smell it
Choose an evenly ripe yellow kumquat with its stalk. Roll it gently between your palms to soften the peel, then squeeze a piece of peel as you would with lime. Smell at once, then again after a minute to catch the floral part at the end — it only shows once the first bright layer has partly gone.
Why this one is hard
Because it is so familiar that people pass it by. The more familiar a smell, the harder it is to describe, because the brain has already labelled it and refuses to take it apart. The way to break that is to smell kumquat straight after lime — the contrast forces the brain to look again.
Don’t confuse with
This entry
Ripe kumquat peel
Citrus family
Kumquat has a faint floral note at the end of the breath, from methyl anthranilate; Vietnamese lime is sharp from start to finish, with no floral note at all.
Scientific note
Kumquat peel contains methyl anthranilate, a nitrogen-containing aromatic ester. It is rare among citrus and is why kumquat has a faint floral note that lime lacks. The same compound gives Concord grapes their smell, and it is the active ingredient in some bird repellents, because birds are very sensitive to it.
In Vietnamese life
The kumquat trees of a northern Tet are chosen for their shape and fruit; almost nobody chooses them by smell. Yet it is the smell of kumquat peel that lingers in many people’s memories of the last days of the year — an example of the sense of smell recording without being asked to pay attention.