How to make coconut soap with used kitchen oil
Updated: Oct 5, 2020
Did you know that 1 litre of used kitchen oil poured down the drain can contaminate 1 million litres of drinkable water? It is also a waste of money – you’ve already paid for that oil, so a smart way to stretch the ‘value for money’ is recycling it.
Unfortunately the UK doesn’t offer a widespread kitchen oil recycling programme – councils usually push people to private schemes such as Proper Oils, (which is better than nothing) but they have few free collection points in West London, and I doubt people living in the East End would cross the city for the sake of saving the planet.
My favourite solution to the oil problem is transforming it into something useful – a nice bar of soap which you can use to clean your house, a sort of ‘second grade’ castile soap. Here’s what you will need:
2 litres of used kitchen oil (strain first to remove any food debris)
500g of pure sodium hydroxide (AKA lye)
300g of dry coconut flakes
700ml of water
1 deep baking tray
1 plastic bucket
Method: Mix the dry coconut with water using a blender or food processor until you obtain a thick paste. Transfer the mix to a pot and cook it in medium heat until ¾ of the volume is reduced. In another pot, heat the oil. Use the plastic bucket to dissolve the lye in hot water (use just enough water to dissolve it, do not put too much or the recipe won’t work). Be careful when handling lye – always wear gloves, mask and open your windows. Carefully add to the lye the coconut water paste and the oil. Mix it well, then pour the soap mixture into the baking tray. Leave it to dry until you can cut it in bars.
Hint: if you stir the soap mix at every 10 minutes, you will get granulated soap, which can be used for laundry.