DIY Laundry Soap from Conkers

Believe it or not, the chestnuts that you step over on your daily lockdown walks are the perfect ingredient to wash your laundry in a sustainable way!

If you spend as much time as I do skulking around Pinterest sustainability boards, you might have heard of Soap Nuts. Soap nuts (or Sapindaceae) are chestnut-like fruit from India and Nepal which, when put into the hot water of a wash, produce gentle soapy substance (saponins). Soap nuts have become very popular among zero-waste and eco-friendly consumers, because of their chemical-free cleaning properties and their lack of packaging.

What you might not have heard is that our own native Horse Chestnuts can do the same thing!

Soap nuts and Conkers are closely related, and both produce the same milky soap that works great as a laundry detergent. There is some debate among the zero-waste community online as to the ethics of using soap nuts, as some argue that the increased demand takes soap nuts away from the locals who need them. There’s no need to worry about this with conkers, nor the air miles required to transport soap nuts from a tropical climate to our own; the only “air miles” with horse chestnuts are carrying them home in your backpack.

I’ve tried out this chestnut laundry detergent for the last two years and it works really well, particularly for anyone with sensitive skin or eczema. After washing your clothes with horse chestnuts, the clothes have no scent, which I really like, but if you really want a scent to your laundry you can add a few drops of essential oils in with the liquid.

Before you start, it’s very important to remember:
Horse Chestnuts are DIFFERENT to Spanish/eating chestnuts. PLEASE don’t eat horse chestnuts, they’re poisonous, like most laundry detergent…
(and I wouldn’t suggest washing your clothes with Spanish chestnuts)

Step 1: Go Collect Conkers!!

This is the fun bit; simply go for a lovely walk to the local park. Pick up a decent amount of conkers. Don’t completely clear out an area, leave a reasonable number for squirrels and children, but certainly in my park there’s no shortage of chestnuts for the local wildlife.

I encountered a squirrel searching for food and threw a couple of my conkers over towards him… and he ran over and started munching on them!

Step 2: Chop & De-Shell

Now we begin the arduous process of de-shelling. Pop on a podcast or an episode of Friends, grab a chef’s knife and a chopping board and go to town. I would advise you to de-shell the chestnuts as early as possible after collecting them; the fresher they are, the easier they are to cut through. But don’t stress out about it, I find that chopping the chestnuts has become a sort of mindless, meditative practise that I do every autumn (similar to knitting, only earning many more dubious looks from my family members… )

Chop the chestnuts into 4 and pry the inner white chestnut out. Each chestnut usually has a little sprout coming out of the round flesh which might be harder to get out of the shell, but I use them too as I don’t like to throw anything out. Again, the fresher the chestnuts, usually the easier it is to get them out of their shells, although each chestnut is slightly different.
(The shells can go straight into the compost!)

Step 3: Drying

The first year I tried this chestnut laundry DIY, I thought it wasn’t worth my while drying the chestnuts out, and stuck the bulk of them in the shed. By a month later, they’d all gone mouldy and I had to throw away a large number of my chestnuts. Drying the chestnuts seems to keep them indefinitely, certainly for up to a year in a sealed container.

Chop up the chestnuts into small pieces (as small as your patience allows) and spread onto a baking tray. I usually dry them by baking them in the oven on a low heat, or by sticking them in the oven as it’s cooling down after cooking.

You’ll know they’re done when they no longer feel squidgy and they sound crisp and hollow when you drop them on the tray.

Step 4: Storing

I keep my chestnuts in various plastic containers and jars – anything airtight will do. Just make sure they’re kept dry so they don’t go mouldy 🙁

Step 5: Using the Chestnuts

Put a handful of chopped chestnuts into a container or jug and cover with a decent amount of boiling water. Leave it for 30 minutes (or overnight) and the liquid will have turned milky – just pour the liquid into the liquid drawer on your washing machine, or into the little drum liquid container if you have one of those.

You can reuse the same batch of conkers a number of times – after a few goes the liquid will get less milky and you’ll know it’s time to switch for some new ones. This depends of how many conkers you put in, how much liquid you put in and how long you soaked them for, but don’t worry too much – it’s not a precise art, it’s mainly common sense mixed with trial and error. After a few washes you’ll get to know how much detergent you need and how many conkers to use!

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