Bilimbi: A Guide to The Tropical Sour Fruit

Bilimbi (Irumban Puli / Chemmeen Puli): A Lesser Known Sour Fruit of the Tropics

Following the encouraging readership and feedback on my earlier article on Passion Fruit, I am tempted to write about another locally available, lesser-known, under-exploited fruit — Bilimbi. Commonly found in coastal India including the Andaman & Nicobar Islands, Bilimbi (Averrhoa bilimbi) is a tropical fruit known for its intensely sour taste. It is widely used in cooking, pickling, and traditional home remedies, valued for its sharp flavour and everyday utility. In the islands, Bilimbi grows almost unnoticed—clustered along slender trunks in backyards and by the roadside. This article explains what Bilimbi is, how it tastes, its medicinal properties, culinary uses, simple recipes for Bilimbi squash and its understated presence in the Andaman and Nicobar Islands.

Image shows Bilimbi fruit clusters on tree - Irumban Puli

The fruit belongs to the family Oxalidaceae and is a close relative of the carambola (star fruit), widely cultivated across the tropical regions of the Philippines, Indonesia, Sri Lanka, Bangladesh, Myanmar, Malaysia, and India. Despite its year-round availability and remarkable versatility, Bilimbi remains one of the most under-utilised fruits in the Indian tropics — and that is precisely what makes it worth writing about.

About the Fruit: Appearance and Taste

The Bilimbi tree produces fruit in clusters directly from the trunk and older branches — a botanical habit known as cauliflory. The fruits are fairly cylindrical in shape with five broad, rounded longitudinal lobes running along their length.

They are typically 4–10 cm long, light green when raw and yellowish-green when ripe.

The taste is intensely sour due to presence of high levels of oxalic acid. It is for this reason that the fruit is rarely eaten raw on its own; instead, it is processed or used as a souring agent in cooking.

Regional Names of Bilimbi

Image showing close up of Bilimbi fruit and its flowers

One of the reasons Bilimbi has stayed so under-documented is that it goes by many names across different languages and regions. Readers often search for what Irumban Puli or Chemmeen Puli is called in English — the answer is simply Bilimbi, or botanically, Averrhoa bilimbi. Similarly, Ilimbi, Ilimbi Puli, and Cheema Puli are all regional names for the same fruit. The word 'Puli' across these names means sour or souring agent in Malayalam, which perfectly captures the fruit's defining character.

Language / Region	Local Name
Malayalam (Kerala)	Irumban Puli, Chemmeen Puli, Orkkaapuli
Andaman & Nicobar Islands	Bilimbi, Bimbul
Other South Indian names	Ilimbi, Ilimbi Puli, Cheema Puli
English	Bilimbi, Cucumber Tree, Tree Sorrel
Scientific name	Averrhoa bilimbi

Traditional and Folk Remedies

Bilimbi has a long history of traditional medicinal use across South and Southeast Asia.

• Fresh Bilimbi leaves are crushed into a paste and applied externally to relieve itching, skin eruptions, swellings, rheumatism, and mumps.

• A leaf-based mixture is used in folk medicine against cough, pimples, and scurvy.

• The fruit is considered useful in treating poisonous insect bites.

• In Thiruvananthapuram and parts of Kerala, Bilimbi has traditionally been consumed to manage cholesterol levels and combat obesity.

Ongoing Scientific Research

The fruit's anti-hyperlipidemic properties — its potential to reduce harmful fats in the bloodstream — are currently under detailed scientific study. Research has also found that the highest levels of Vitamin C and Total Soluble Solids occur in fully ripe Bilimbi harvested during the dry season, with the lowest levels of oxalic acid at that stage. This makes ripe, dry-season Bilimbi the most nutritious and safest for regular consumption.

Culinary Uses: Pickles, Jams, Curries and More

Despite its intense sourness, Bilimbi is a versatile ingredient in tropical kitchens. Its round-the-year availability makes it a reliable souring agent wherever it grows.

• Souring agent in curries and fish dishes — used in Kerala fish curries in place of tamarind or raw mango (one reason it is called Chemmeen Puli, meaning 'prawn sour,' in some coastal communities)

• Pickles — a very popular use across the Andaman Islands and Kerala

• Jams and jellies

• Vinegar and wine production

• Soups and sauces

• Squash and fresh juice

How to Make Bilimbi Squash at Home

Bilimbi's tangy flavour makes for a refreshing summer drink. Here are two simple methods:

Method 1: Concentrated Bilimbi Squash (Bottled)

1. Take 1 kg of ripe Bilimbi fruits. Wash them under running tap water.

2. Cut into pieces and extract juice using a household lemon juice extractor.

Image showing the steps of making Bilimbi Squash

3. Add one cup of water to the juice extract and set aside in a glass bowl or jar.

4. In a separate pan, combine 500 ml water with sugar/salt (to taste) and 2 tsp citric acid. Mix well.

5. Bring this sugar syrup to a boil in an open pan, stirring occasionally and skimming off any floating matter.

6. After boiling for approximately 15 minutes, remove from heat and stir in the Bilimbi juice extract.

7. Allow to cool, then transfer to a clean, dry glass bottle (500 ml). Seal well.

8. To serve: dilute in a ratio of 1 part squash to 3 parts water.

Method 2: Instant Bilimbi Drink

1. Take 8–10 ripe Bilimbi fruits, wash and extract the juice.

2. Add the juice to four glasses of water in a jar.

3. Add salt and/or sugar to taste and stir well.

4. Serve immediately over ice.

Important: Only fully ripe Bilimbi is recommended for consumption. Studies confirm that ripe fruits during the dry season contain the lowest oxalic acid and the highest Vitamin C levels.

Common Household and Industrial Uses

The high oxalic acid content in Bilimbi, which limits its raw consumption, turns out to be useful in several non-food applications:

• Stain removal: Bilimbi juice can remove iron-rust stains from fabrics and clean sanitary ware effectively.

• Polishing brassware: The acid imparts a natural shine to brass items.

• Natural dye: In Indonesia, red Bilimbi flowers are used to extract a red dye for traditional textiles.

Availability and Cultivation

Image showing Bilimbi fruit clusters on tree - Irumban Puli

Bilimbi is a tropical tree that thrives in warm, humid climates. It is commonly found growing in home gardens, along roadsides, and in forest edges across Kerala, Tamil Nadu, the Andaman and Nicobar Islands, and coastal Karnataka. The tree fruits almost year-round, making it a dependable source of produce for home use.

Despite its abundance, Bilimbi remains commercially underutilised in India — a missed opportunity given its culinary versatility, medicinal potential, and suitability for value-added products like pickles, squash, and jams.

A Note of Thanks:
Written with inputs from Dr TVRS Sharma, Emeritus Scientist, CARI, Port Blair.

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