What are soap berries?
Sapindus mukorossi is a species of tree in the Sapindaceae family. The whole key is that the family of sapindus plants produce fruits containing saponins (natural surfactants / i.e., soap) in high enough concentrations that they are being recognized as a marketable commodity of significant value. Many plants contain saponin (such as agave, yucca, soapwort, etc.), but only soapberries contain enough of the precious saponins to make them a practical, sustainable, and economically viable source of it.
How do soap berries work?
The sun-dried berries used for detergent contains saponin, which works as a natural surfactant. Surfactants reduce the surface tension of the water, essentially making it wetter and easier to penetrate into soiled fabrics. This combined with the agitation of your machine or handwashing removes the dirt or particles, then keeps them away from your clothing until rinsing occurs.
Most commercial detergents contain chemical surfactants, some of which (such as 1,2-Dioxane) have been shown to be carcinogenic and volatile. But soap berries are all-natural and have been used for centuries around the world.
It’s the combination of the tree’s prolific fruit bearing capacity, and its hardy nature that make annual harvesting possible. One tree can produce 60 – 80 pounds of fruit per year. Other known saponin producing plants don’t produce enough saponin to make them viable or sustainable as a resource.