Reference point
A piece of tangerine peel dried and aged for years, bought from a traditional medicine shop.
Do this before you read on. An entry only works when you have just smelled the thing.
Nothing of the fresh fruit is left. The bright part evaporated years ago, and what remains is a dry, warm, slightly bitter smell with a woody note and a touch of honey.
This is the typical way the citrus family reaches the middle stage: time. Buddha’s hand and the gold apple get there through the structure of the fruit, passion fruit through its sulphur compounds, and aged tangerine peel through years of oxidation. The whole family evaporates too quickly to have a middle stage unless time does the work: limonene slowly oxidises into heavier compounds, and the lightest part has long gone.
The older the peel, the more expensive it is, and expert buyers judge it by nose rather than by the year on the label. Three-year-old and ten-year-old peel differ in that the older one has lost all sourness and kept only the warmth.
How to smell it
Break a piece of aged peel to expose the inner surface and smell it at once. Then squeeze a piece of fresh tangerine peel and smell it. The two come from the same source, a few years apart, and have almost nothing left in common. This is the best exercise in the dictionary on what time does to a smell.
Why this one is hard
Because people expect tangerine. Aged peel is not dried tangerine but a new smell, formed through slow oxidation. Letting go of that first expectation is the condition for smelling it.
Don’t confuse with
This entry
Aged tangerine peel
Citrus family
Same citrus family, but years apart. Fresh peel is bright and fast; aged tangerine peel is dry, warm, bitter and has almost no sourness left.
Scientific note
Long storage slowly oxidises limonene into carvone, perillyl alcohol and many heavier derivatives. Molecular weight rises, vapour pressure falls, and the smell moves from the top stage to the middle. That is why old peel is valued more than new: time has done a job no technique can replace.
In Vietnamese life
Aged tangerine peel is one of the few ingredients that Vietnamese and Chinese traditional medicine value by age, like wine. It appears in dozens of remedies and in many southern braised dishes, always as a background rather than the main aroma.