Making conker soap

We've been enjoying collecting acorns and conkers on recent Autumnal walks in our local parks, and I thought we should find a use for a few of the many conkers (collected from under horse chestnut trees).  They contain saponins, soap-like molecules where one part of the molecule is hydrophilic (attracted to water) and one part is lipophilic (attracted to fats) so they help to dissolve grease/dirt in water.  You could go about making this soap in such a way that you could actually use it for washing, but as we made ours in a 'mud kitchen' setup with some pots and pans that have been hanging around in our garden all summer, it was more of an experiment/demonstration!

Conker pieces

I gave the conkers and the mud kitchen pan/colander a cursory wash to remove the worst of the dirt, and then we broke the conkers into pieces.  This is a bit of a challenge for a 3 year old, and we resorted to some pliers and a lot of adult assistance!  The next part needs some care as it involves very hot water, and we did it whilst my younger son was napping to avoid accidents.  I was going to pour the hot water (boiled kettle left for a few minutes) over the conkers in the pan, and then strain them afterwards, but my son thought we should put the conker pieces in the colander and then pour the water over them.  I conceded the point, as the large pan we put the colander inside meant this worked, but the original plan is probably preferable!

After adding hot water

As soon as I poured the hot water on, a yellowy-green liquid appeared, and the colour increased over a few minutes.  We left it for 5 minutes, during which I gave my son a well-worn white muslin and asked him to make it dirty with grass stains and dirt.  He looked pretty horrified and I explained that it was to test the soap, but he still wasn't sure, so I did it myself...

Soapy bubbles

I got a washing up bowl of tepid water and asked my son to wash the cloth and see if he could get rid of the stains.  He set to work, and tried pretty hard, but they wouldn't really budge.  We then went to have a look at the soap, and removed the colander of conkers.  I gave the liquid a swirl and some bubbles appeared - I asked him if it looked like soap and he thought so, because it foamed.  We then poured some into the washing up bowl (quantity-wise, this was probably the equivalent of a single conker) and I asked him to see if it worked.  

Washing a dirty cloth

It certainly wasn't as good at stain removal as the leading brand(!) but it did start to shift the dirt.  My son wasn't keen to persist, partly because I think he'd put too much effort in with just the water, so we hung it up to dry.  He was keener on splashing the water to see the bubbles appear, and seemed happily convinced that we'd made a type of soap.  It was a nice demonstration of how we can find useful substances in nature, and I've read some historical references to the use of soap made from conkers although I have no idea of the accuracy.