Reference point
Open a jar of limes salted for more than six months and smell the brine.
Do this before you read on. An entry only works when you have just smelled the thing.
Sour but not sharp. The zing of the peel has disappeared, replaced by a salty layer and a deep bitterness at the end.
This entry shows that the citrus family does have a lasting side. Fresh lime is gone within minutes; salted lime stays on the hand for hours, because salt and time have broken down the light components and left the heavier ones.
Don’t confuse it with fresh lime squeezed into fish sauce. That is still lime; this is something else that has taken shape.
How to smell it
Open the jar, take a little brine with a clean spoon and drop it on the back of your hand. Smell at once, then again after ten minutes. Do the same with a slice of fresh lime on the other hand — the difference in how long each lasts is the lesson of this entry.
Why this one is hard
Because people expect sourness and skip the smell. Salted lime is clearly sour on the tongue, but in the nose it leans towards salt and bitterness, and taste easily covers both.
Don’t confuse with
This entry
Salted preserved lime
Citrus family
Salted lime is still moist and salty; aged tangerine peel is bone-dry, with a note of traditional medicine. One is steeped, the other sun-dried.
Scientific note
Salt draws water out of the peel by osmosis and creates an environment most microbes cannot survive. Light monoterpenes such as limonene evaporate or oxidise over the months, while the heavier group stays. That is why a lime preserved for a long time has an evaporation profile shifted far to the right of its fresh self.
In Vietnamese life
Salted lime with ice water is a popular summer drink across southern Vietnam. Many families keep a jar for decades and believe the older the better — the same way people talk about fish sauce and fermented soybean paste.