Conker Cleaners

Seed (conker) of the European Horse Chestnut. NOT for eating!

This week I washed my clothes with European Horse Chestnuts.

I’d read recently online that the seed of horse chestnut trees is one of those plants that are high in saponin, a naturally occuring soaping agent that can be used for washing clothes.

Not familiar with horse chestnuts? They belong to a large decidious European tree of the same name with long leaves. In late summer you can find their plum sized spiky green seed pods that split open to reveal glossy brown chestnuts.

I’m talking about the conkers of our childhoods!

The plant containing the most saponin is reported to be the dried fruit of Sapindus Mukurossa, a tree that grows in the Himalyas and neighbouring countries such as India. In New Zealand, we call them Soapnuts and you can buy them in bulk (to avoid plastic), as well as bags.

I enjoy using soapnuts – but I’m not the only one. As more people everywhere rightly get excited about living more sustainably, more soapnuts are getting shipped overseas. I’m not fretting over the environmental sustainability impacts of soapnuts – this is a slow maturing tree (not a high return plant like palm oil) and freighter ship travel is in fact much lower in carbon emissions than road freight. But the blog I read reported that Europeans are inflating the price of soapnuts and making them unaffordable for locals in India to buy. I couldn’t assess the supporting evidence because it was in German – so I just don’t know.

This is what I like most about local production – that we can observe. We are not blinded by distance.

So how did I get on with my horse chestnuts that I gathered last week in Dunedin? Well I vaguely followed the advice on the blog site that my friend Jennie had found. I ground up the conkers with my very sturdy food processor. Then I poured hot water over the pulp, and let it soak for an hour to draw out the saponin. What resulted was a thick, whitish liquid that was not frothy. I fine-strained the liquid only into the tray of my front loader and turned on the machine. The clothes emerged looking fine. However there was still some armpit odour lurking on a tee-shirt.

I’ve got a bag of pulp left that I’m storing in the freezer so I’ll try again, this time soaking the pulp overnight, to see if more saponin is released. If I’m happy with the results, I’ll need a different way to process them that’s easy and doesn’t involve my precious food processor. These chestnuts are seriously hard!

If you are intrigued about conker cleaners, there are plenty of them still falling off trees. I’d love to hear how you get on if they end up in your washing machine.