Homemade laundry detergent

How to make liquid laundry soap from ash in 10 easy steps

TL;DR : There are many ways to make soap from ash. This post is about making liquid soap from ash for your washing machine. So do not expect an explanation on the fine art of recycling hardwood ash and left-over kitchen fats into clean, all purpose soap! Hopefully that will be for another time.

Are there different types of soaps ?

Liquid detergent and soft soap

With potash (potassium) and fat (you can use many types of fat of course : animal or vegetable) you’ll get a blackish liquid or soft soap like liquid or soft black soap. This type of soap is very popular for gardening (as a repellent) and washing, in France. It usually smells strongly of olive oil over here (yes, we like our olive oil). Soft soap is traditionally made by undertaking saponification with potassium, instead of sodium hydroxide (used to make hard soap, which will only dissolve sparingly).

Black soap comes in different forms : liquid or soft soapBlack soap or “Savon Noir” in France comes in different forms : liquid (savon liquide) or soft (savon mou) soap.

Hard soap : Soap bars

With sodium hydroxide (also known as lye or caustic soda) and fat you’ll get the hard soap you might be looking for. It’s the kinda of thing you use to make Savon de Marseille for example (oooh no, more olive oil).

There are so many diferent types of hard soapThis is what the hard soap Savon de Marseille looks like.

Lye is a white solid and highly caustic metallic base and alkali salt of sodium which is available in pellets, flakes, granules and as prepared solutions at a number of different concentrations.

Our method for making homemade liquid soap is even easier than this !

So you want to learn how to make free laundry detergent ?

Using this kind of soap is not only cheaper (read free) but also much better for our planet.

The main ingredient for this recipe is ash. People who’ve done some camping probably know that if you throw some white ash from a hardwood fire into your frying pan after dinner, the lye in the ash will combine with the fat from the cooking to make a crude soap. This experiment is just as easy, without any fat or cooking. All you need is ash and water, and a few drops of essential oil (to get that fresh smell). You can basically make your laundry smell anything you like, from sensual ylang-ylang to fresh pine!

So what kind of ashes ? And where should you get this ash ?

Depending on what material you have on hand you can get great ash from different places.

Some plants are rich in potassium :

  • Ferns (these are also great to start fires, better than firestarters)
  • Tobacco (yes you can use these ashes if you’re a smoker)
  • Banana peels (you must have already heard than bananas are good for you because they are full of potassium, well so are there peels).
  • Corn silk
  • Buckwheat straw  works pretty nicely too
  • Potato peels

These are only a few examples. Of course if you want enough ash usually the easiest way is to use the ash from your fireplace (if you have one). Wood ash works great. Some types of wood better than others of course. If the wood you burn isn’t rich in potassium you can add some of the previously cited materials to your fire.

Wood ash is very rich in potassium

When you burn wood this is usually what you get (well at least that’s what I read) :

  • 17 to 33 % calcium
  • 2 to 6 % potassium
  • 2,5 to 4,6 % magnesium (MgO)
  • 1 to 6 % phosphorus (P2O5)
  • 3 % oxides (iron, manganese, …)
  • and lots of other stuff in smaller quantities

Step by step guide to make liquid soap from ash

Ingredients and material needed

Here is what you’ll need :

  • Two clean buckets or large containers (depending on the quantity you’re hoping to make)
  • A few liters of water (rain water preferably)
  • Wood ash
  • A large wooden spoon
  • A sieve (preferably a large one)
  • A few empty bottles
  • Essential oils of your choice (optional)
  • A few clean tea towels or other types of cloth to use as filter
  • A large bowl

You’ll need approximately 2 / 3 cups (100 grams) of ash per liter of water. 100 grams of ash contains a little less than 10 grams of potash (depending on your ashes).

You’ll also need around 10 drops of essential oil per liter of liquid soap.

You’ll get approximately 2/3 of a liter of detergent for every liter of water you add (unless you really press the ash, but it’s a lot of effort for not much more reward).

You’ll need about 2 two cups (or 100 ml) of this liquid soap for every batch of laundry, so make the right quantity of soap to last you a few weeks.

How to make your own laundry detergent from ashes

  1. Set up your little “lab” in a well-ventilated area like the garden, on your porch or your balcony. You might also want to avoid doing this on a windy day; eating ash isn’t very yummy.
  2. Use a sieve on your ash to make sure you have no nails, cigarette butts or large chunks of burnt wood in your powder. (Sorry for the blurred image, I might change it for a better one next time I make soap !)You'll probably have nails or not completely burnt piece of wood in your fireplace
  3. Once you only have fine ash measure the quantity of ash you’ll need for the quantity of soap you want. Reminder : you need approximately 2 / 3 cups (100 grams) of ash per liter of water. You’ll get approximately the same amount of detergent as the amount of water you add in the end.
  4. Dump your ash and the corresponding amount of rainwater in one of the large clean buckets.You'll need to fill a large bowl with ash
  5. Use a large wooden spoon or your hands (your skin might dry a little from this) to mix this all in.
  6. Leave it to sit for about 48 hours, stirring once or twice per day during this period.
  7. Set up to second bucket and put a large sieve (you can also use a large funnel) on it with two tea towels or fine cloths in order to filter out all the ash.
  8. Pour in your mixture slowly, letting the water leak through progressively. The liquid you should get should be clear and a little yellow (tea coloured). There should be no deposits at the bottom of you bucket. If there are, you should filter it again (possibly with new, finer cloths) until nothing sits at the bottom of your container.
  9. Pour your liquid into your empty bottles and add your essential oils : lemon, lavender, … 10 drops per 1 liter.
  10. Shake your bottle to mix it in and you’re all set ! 100 ml per batch of laundry. Keep on reading to learn what you can do with the leftover ash (in your tea towel).

The colour of your may vary depending on the quality of your ash and on your filtering

If you want your laundry to be even whiter just add a couple of spoons of baking soda with your cup of ash detergent at the moment you pour it into the washing machine.


  • Don’t get carried away and make too much at once (especially if you’re only doing laundry for one). You can keep ashes forever but your detergent might not be so nice after a few months.
  • Don’t use this for dishing washing.
  • Potash and this type of soap (just like lye) without saponification will dry your skin if you intend to do your laundry by hand, so please wear gloves if this soap is not destined for your washing machine.
  • Don’t use this soap to wash your floors unless  you are sure to rinse them out thoroughly.
  • Depending your ashes your soap might be more or less corrosive, avoid washing delicate laundry with this soap.

What should you do with your leftover ash ?

Well now you have your soap in your bottle. You also have a bunch of leftover ash in your cloth. Don’t let it go to waste. There are a few things you could do with this ash.

Spread it in your garden

You can add these to your compost (they are full of minerals and can also alter your pH levels), you could also add them in small quantities around the base of your plants or your garden beds. Ash is a great snail and slug repellent. Small gastropods hate ash. We’ve already talked about this in our post on why plants have holes in their leaves .

Make scouring cream from ash

You can also use this ash to scrub your sinks, your shower tray, …. Keep it in a jar and every time you need it just add a spoonful on your sponge and get scrubbin’. Rinse out with water mixed with some white vinegar (two parts water, one part vinegar).

Do you also make your own soap / detergent / cleaning products ? Please share your tips, remarks and questions in the comment section below.

One thought on “How to make liquid laundry soap from ash in 10 easy steps

Leave a Reply

Your email address will not be published. Required fields are marked *