• Jennifer Huang

Lerak: the traditional natural detergent that you should use to wash your batik clothes

Updated: Nov 11, 2020

Article written by Kreta Kei - Founder of @greenability_id

Lerak (Sapindus rarak De Candole, or Sapindus mukorossi), also known as rerek or lamuran, is a plant known for its use as a traditional detergent. They are commonly used to wash batik cloths because they are considered to be the most suitable washing agents to maintain the color quality and batik ingredients.

Dry lerak


Lerak seeds contain saponins, active ingredients that produce foam and function as washing agents. The cleaning benefits of lerak can also be extended to kitchen appliances, floors, and even to bath pets. It has also been used widely as a vegetable pesticide in home-scale gardening.

And there is more. Lerak can also be used as a substitute for facial soap, bath soap, as a hair growth vitamin, and to heal callus. Some research have specifically said that lerak rind can be used to reduce facial acne and scabies.

Where to find it

The lerak fruit is relatively easily found in online stores and traditional markets in certain areas. It's also possible to find the liquid lerak product in the market for more practical and immediate use.

The uses of lerak

The old lerak fruit is blackish brown, sometimes shiny. The surface looks like a palm fruit at a glance, but when touched, the texture is harder. Before used, lerak needs to be processed into liquid by soaking it or boiling it in water. The soapy water can be used as needed. The already soaked and boiled lerak fruit can be kept being soaked/boiled many times until it no longer produces saponins (brown active substances that feel sticky and foamy).

Products that can be made from lerak:

  1. Liquid soap, multifunctional cleanser

  2. Raw material for soap bars

Why is it eco-friendly?

Lerak as a natural soap is often referred to as an environmentally friendly product. This is because the saponin produced by lerak won't pollute the water and the surrounding environment like in the chemical detergents. In addition, the use of lerak also does not produce waste, as the used fruit can be used as compost, unlike plastic waste from detergents.

Besides that, the foam produced from lerak is different from the commercial soap synthetic foam. Lerak has a light foam that disappears quickly, and makes us use less water when washing.

Where does our lerak come from?

The lerak fruit supplied by our partner Greenability comes from West Nusa Tenggara. The fruit is taken from trees that grow wildly in the forest by local farmers who harvest the fruit in their spare time. The farmers maintain the lerak trees sustainability, and only harvest the fruits when needed.

The revenue generated from picking lerak fruit is considered sufficient to increase income during hard times. To travel through distant and difficult forest terrains, the farmers must rent a pickup car (which is not always available to them). Due to the terrain difficulty, not many farmers want nor are able to harvest lerak fruit. Most of the ones interested in picking lerak are in their 40's-50's age range. The rainy season also makes it difficult for farmers to harvest the fruit because lerak trees become more slippery.

The cons

With the many advantages, lerak can also have some negative aspects. For a small number of people, the benefits can actually be the contrary as it can cause allergies, and make the skin itchy.

How to make lerak soap

1. Because dry lerak is still hard and cannot excrete saponin (its natural cleaning agent), it needs to be soaked for 2 days in advance to soften.

2. After 2 days, the dry lerak will have absorbed water and softened, and saponins will come out (by being squeezed / sliced beforehand). You will notice that saponins are light brow.

3. Prepare a pot to boil the lerak. Make sure the saponin has come out. 100 grams of lerak can be boiled with 1200 ml of water.

4. Turn the stove on high heat. After it reaches boiling point, turn it down to low heat and steam it for 15 minutes. After that, let it cool down and move it to a bottle.

5. Strain the liquid into a bottle. The initial 1200 ml of water will shrink to about 600 ml.

6. The boiled lerak fruit can be stored by being soaked in water. It can also be directly used to wash clothes and dishes.

To wash dishes:

To do laundry:

Squeeze the lerak, put in the bag and then put in the washing machine. The ratio is about 5-6 pieces of lerak for 6-7 kg of clothes. Approximately 1 lerak for 1 kg of clothes.

How to use liquid lerak

  • To wash clothes: 50 ml + 1 liter of water, or as desired.

  • To mop the floor: 2 tablespoons + 1 liter of water. Mix the lerak until the water mixture has turned turbid. Do not exceed, otherwise the floor will feel sticky.

  • Do not use lerak to wash bright colored clothes regularly.

  • It can be a used as multifunctional soap when traveling (laundry, dishes, body, head to toe)

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