The fruits of this soap tree make the sustainable dream possible for anyone who loves caring for the environment; maintain cleanliness without contaminating the planet with toxic chemicals. These are ‘washing nuts’, which are the fruit of a tree typical of Asia and America, and are positioned as one of the most ecological alternatives that exist compared to soaps made with chemicals that are harmful to nature.
The soap tree (Sapindus saponaria)
Washing nuts are typical of Nepal and India, where they have been known since ancient times and have been used for centuries as soaps for washing clothes and even the body itself. It is to be expected that a fruit born from nature itself is so respectful of the environment that it can even be used in rivers without the risk of contaminating the ecosystem. It is for this reason that they are of great value and become more popular every day.
This type of fruit comes from the tree known as ‘soap tree’ whose scientific name is Sapindus saponaria. It lives mainly in Asia, in countries such as Nepal and India, although it can also be found in tropical and subtropical America. The tree can reach a height of up to 15 meters and once its flowering season arrives, which is between March and April, it covers its foliage with white. Then over several months, the flowers mature into fruits that are very similar to walnuts or hazelnuts in color and shape. They are harvested in the season that runs from September to October and are used as natural soaps.
Washing nuts differ from other fruits because they contain a substance known as saponin that, when combined with it, produces a natural soap with a powerful action to clean fabrics, surfaces and is even capable of cleaning the skin without damaging it.
Washing nuts are known to have been used by the ancient people of Mesoamerica until the arrival of the Spanish brought the use of lye and other cleaning substances. In Nepal and India they are still used, although to a lesser extent than centuries ago.
How do wash nuts work?
Once the fruits of the soap tree are harvested, they are dried and peeled, putting the shells aside. These are the ones that contain the compound known as saponin whose main characteristics are detergents.
Saponin is a glycoside substance that has effects similar to those of soap because each molecule is made up of a lipid-soluble element and a water-soluble element. This is why when the washing walnut shell is squeezed in preferably warm water, it releases a kind of foam similar to soap, although much lighter. And if that were not enough, the aroma is not a problem as it has a very pleasant neutral soap smell, although if you want a more penetrating aroma, you can add natural flavorings.
To use the washing nuts it is necessary to squeeze them in water with a temperature of at least 30ºC so that the shells release the saponin and work optimally as a soap. Although if cold washing is required, you can boil the peels for at least 5 minutes, the result will be a liquid soap that can be added to the clothing or surface you want to clean.
Nature is wise and provides us with everything we need to survive, it is enough to find the necessary alternatives to lead a more planet-friendly lifestyle and leave aside habits that are harmful to the environment.