One of the abundances of the autumn or fall season is horse chestnuts – the non-edible chestnut relative. If it’s not edible, what use can it possibly have, right? Well, horse chestnuts have an amazing superpower – they are incredibly rich in saponins, which makes them a fantastic soap.
How does it work?
Horse chestnut leaves and seeds – the conkers – are rich in saponins. Saponins are a group of naturally occurring plant glycosides (phytochemicals) that are present in foods such as soybeans, peas, chickpeas, mung beans, peanuts, kidney beans, and lentils and are said to have cancer-fighting properties. This isn’t relevant to horse chestnuts though, since they aren’t edible. What saponins also do have, however, is detergent qualities that foam when mixed with water.
We wanted to share this with our forest school kids, so we did a few experiments on making soap from conker leaves and seeds.
Method one – soaking
Thinking that the soap might need some time, we put leaves and seeds into two different containers and left them to soak for two days. Interestingly, the colour of the water came up completely differently in the two. It also has a ‘thick’, smooth feeling, to touch, a little like glycerin. When it came to testing it out with the kids, we poured the contents of both tubs into a bucket of warm water and swirled it around to make a brilliantly foamy concoction. The truly fascinating thing about this particular session was how the younger children dipped conkers on strings in and out of the bucket for almost a full two-hour session, watching as the agitation of the water made it soapier.
Method two – smashing
We realised with further sessions that there may not always be the time to soak leaves and seeds for days, but if you crush the conkers, either through playing conkers – a game that actually originated here on the Isle of Wight – or bashing them with a stone or hammer, it achieves the same effect – drop them into hot or cold water and agitate, and away you go! So much fun for little ones!
That’s great… but so what?
You can actually use conker soap in washing your laundry. This is really significant when you think about soap nuts and how they are touted as being environmentally better, yet are shipped in from places like India – and the impact that must have on local supply too. Why, when we have something perfectly usable right here!
To make soap nuts into a laundry soap:
- Collect as many conkers as you need (40g should see you through about 3l or six washes, so work out how much you might need) seeds without their shells, and crush them with a hammer or stone. Place them in a dehydrator or oven on low heat. They must be completely dry or they will go mouldy.
- Once they are totally dry you can keep them in a sealed tub for as long as you need.
- To make the laundry soap, place 40g of the conkers into 500ml boiling water and leave to soak for about half an hour. Pour the liquid through a sieve and you can reuse the conkers two or three times. The liquid will become weaker with each soaking, so use the first soak for dirtier laundry and the second and third for less soiled goods. Used up conkers will be white as their yellow colour is leached out.
- Keep the liquid in the fridge for up to a week, using about 250ml in each wash – and you can add a drop of your favourite essential oil if you miss a fragranced washing liquid.
- One note of warning – this will potentially make your whites whiter, but it may also dull your darker colours with prolonged use.