Make Homemade Soap From Ashes

Make Homemade Soap From Ashes @ Farming My Backyard
There are a few things you just don’t want to live without.  Soap is definitely one of those things. Whether you want to be prepared for a disaster, are interested in cultivating lost arts, or are really into DIY everything, making your own homemade soap from ashes is a great skill to have.
Since I have a steady supply of ashes from our wood stove, I figured it was time to learn how to make my own soap. I originally followed the directions for Grandpappy’s Homemade Soap, but it looks like the site is gone now.  You can still read the original article through the Wayback Machine though.

Homemade Soap Ingredients

Making soap only requires three essential ingredients, ashes, rainwater, and fat.  The type of fat doesn’t matter much, you can lard just as easily as you can use coconut oil.  This type of soap won’t be exactly the same as soap you purchase from the store, or soap made from lye crystals.  It will softer, and a little more oily.  It also won’t bubble, commercial soaps have additives such as sodium laureth sulfate that are foaming agents.  Even though it’s not bubbly it’s still great and cleaning things, and as some people can find sodium laureth sulfate irritating it’s nice to have soaps without it. 


You’ll also need a stainless steel pot, a glass measuring cup, a long handled spoon, and molds to pour the soap into to harden.  I used plastic tubs from my recycling bin as molds, but really you can use anything as long as it is at least an inch or so deep.  A thermometer can also be useful. (Missing something you need?  Feel free to use one of our affiliate links and support the blog at the same time!)

How to Make Lye From Ashes

To make concentrated lye water you need to pour rainwater through cold ashes, hardwoods are best.   You need a plastic bucket or clay flowerpot with a hole in the bottom.  Cover the hole with a layer of pine needles to keep the ashes from falling straight through.
Straining Ashes for Lye @ Farming My Backyard
Tightly pack your ashes on top of the pine needles.  Ten cups of ashes will make about a gallon of lye water.  I was an overachiever here and filled my whole bucket.  Make sure to leave a few inches at the top to hold the water. 
Making Lye Water From Ashes @ Farming My Backyard
Next you need to set your bucket up so that the water can drip down through the ashes, out the hole in the bottom and into your stainless steel pot below.
Making Soap From Ashes @ Farming My Backyard
If you have rainwater, heat it to boiling.  You can use steam distilled water, but regular tap water has too much chlorine and minerals in it.   Pour a half gallon of the boiling water over the ashes.  Once that has seeped down, pour another half gallon and wait 30 minutes before pouring another half gallon into your bucket.  If you don’t have a gallon of brown lye water in your pot, pour another one half gallon in 30 minutes.  
Purify Rainwater for Making Lye With Ashes @ Farming My BackyardRainwater for Making Lye @ Farming My Backyard
You are done pouring as soon as you have a gallon of brown lye water in the pot below your ash bucket.  The used ashes should be discarded, you can put them in the compost bin to break down.  If you need more lye water, repeat the process with fresh water and ashes.  Ten cups of ashes and one and a half to two gallons of rainwater will make an average strength lye, so there’s no need to test the strength.  The finished soap will vary a little in strength, but you can use slightly stronger soap for laundry, and slightly weaker as a bath soap if it varies too much.  
Brown Lye Water From Ashes @ Farming My BackyardAfter extracting the brown lye water the next step is to boil it until the lye is more concentrated. When starting with ten cups of ashes, you should boil the brown lye water until you have just 3/8ths of a cup concentrated lye water. Obviously I ended up with more then that, due to my overambitious bucket of ash.  This should take three to four hours.  Once you get down to about a quart of concentrated lye water in the pot you should watch it carefully so as to not boil off all your water.  If you do go below 3/8ths of a cup, carefully add enough rain water to bring it to 3/8ths.  Be very, very careful with the lye!  Wear gloves, and be super careful not to splash or spill!
Boiling Down Lye from Wood Ash @ Farming My Backyard

How To Make Soap From Homemade Lye

Combine Oil And Brown Lye Water for Soapmaking @ Farming My Backyard

Making your own homemade soap from ashes is so easy once you have your concentrated brown lye liquid.  Start with the ratios below, and keep notes on how your batches turn out so you can make minor adjustments for future batches.

  • Warm up two cups of grease in a small pan on low heat.  You can easily render your own lard or tallow from pork of beef fat. 
  • Pour 1 cup grease into stainless steel soapmaking pot
  • Slowly add your 3/8 cup concentrated brown lye water and stir for three minutes
  • Add another cup of grease and another 3/8 cup lye water and stir for fifteen minutes
  • Keep the soap warm (between 90 degrees and 130 degrees depending on what type of fat you are using.  You can place a towel over the pot when the heat is off.  
  • Stir vigorously for one minute at a time, letting the soap rest for 10-15 minutes between.
  • Watch for the soap to be a solid cream or light brown color with no streaks before stirring, and is thick like pudding.  This can take 30 minutes or up to 3 hours.
  • Check for tracing by drawing a line with your spoon.  If you can see the line, the soap is done.  Or you can drop a little of the mixture from above, if the drop stays on the top for a moment it is done.
  • Pour into molds and cover with a towel to hold in warmth
  • Remove the towel after the first day and let the soap rest for six days
  • Remove the soap from the molds and cut to size
  • Air dry for 2-6 weeks, rotating halfway through.
  • Store finished soap in an airtight container, or wrap in plastic



When I tried, I couldn’t reach a trace state and got fed up with the lack of action, so I just ignored it for about the next five days. I’d check on it a couple times a day, stir the lye and oils together, get mad and leave it again.  I don’t really think it benefited the soap at all to be ignored. Nor did it hurt its feelings, so all I really accomplished was feeling annoyed every time I looked at my “failure”.  Finally, I needed my pot back, so I began troubleshooting based on the instructions on Grandpappy’s website. I heated the oil and lye mixture and it came together a little but I still wasn’t achieving a trace state like it should. I added in more lye and almost instantly the mixture began to thicken up.
At this point I started jumping around the kitchen and shouting “I made soap! I made soap!” Then I came to my senses and poured it into my molds. (Well, the plastic food containers I was using as molds. Before this, they were watering cans for the kids, before that they sprouted seedlings for my garden, and before that they held leftovers, and before that…. well you get the idea).
BUT, here’s how to fix some potential problems without leaving a pot sitting around your house for a week and glaring at it. (That doesn’t work anyway).
 If your mixture has a layer of grease on the top, make sure it is warm enough to keep your grease liquefied.  If it’s cold, warm it up slightly.  If it is already warm, heat it a little more add 5% more lye water and stir for 10 minutes.
If your mixture isn’t thick within three hours heat it a little, turn off heat, add 10% more of the melted fat and stir for 10 minutes.
If your soap doesn’t harden, make sure you used hardwood ashes, not softwood ashes. (I did this, oops!).
If brown water pools under your bars during the air dry phase, pour it off and add 10% more fat to the next batch.
If the finished soap has a thin layer of white dust on the top, just rinse off this extra lye with water before using. 
If the finished soap doesn’t work well the first time you use it, dip in water and air dry several times to help it adjust.
Making Soap From Wood Ash @ Farming My Backyard
 Even though my first attempt never hardened (I used the wrong type of ashes), it still made an amazingly effective dish soap.  It was soft and gloppy, but the dishes were super clean, and it did awesome things for my cast iron pans.  We burn mostly softwood in our wood stove, but one of these days I’ll stockpile my hardwood pieces and try making homemade soap with the right type of ashes.  😀 
Posted in Frugal Homemaking
8 comments on “Make Homemade Soap From Ashes
  1. amber says:

    Oh-my-gosh. You are soooooo cool! I can’t WAIT to make soap! But you made your own lye…. I may never reach that level of cool! Just AWESOME.

    • Kathryn says:

      Oh this totally reminds me that I need to do a part two on this post! The soap never hardened, it stayed kind of like a liquid dishsoap. It worked well, but it never turned into bars. I just learned that it’s because I have ashes from soft woods instead of hard wood, so I need to round up some ashes from hard wood and see if that really does make a difference.

  2. Would this be the link you need for ‘Grandpappy’s soap”. It is the one I also first used to learn. 😀

  3. Chris says:

    I loved this post. Thanks for sharing your process.

    I don’t think you’ll be able to make hard bar soap with wood ashes. Wood ashes leach potassium hydroxide. Hard bar soap is made with sodium hydroxide. Both are called lye, so this is confusing.

    Potassium hydroxide is the kind of lye used to make liquid soap, like Dr. Bronner’s Liquid Castile Soap. Or the kind of soap in the foaming soap bottles. While sodium hydroxide is used for hard bar soaps.

    My understanding is that hardwood ashes will give you a stronger lye than softwood ashes, but you’ll still have potassium hydroxide, rather than sodium hydroxide. Which is not bad, it’s just different. You did make an amazing liquid soap that should be great in the washing machine. And it won’t go solid on you, which is what happens when people take solid bar soap, grate it and add water to make laundry soap. (Been there, done that.)

    On the otherhand, I came here specifically to find out how to get potassium hydroxide from my wood ashes, so I could make liquid soap. So thanks very much for your tutorial.

  4. Kristensom says:

    I know exactly what happened with your soap! Just because I am studying recipes to make my own soap. You put in The incorrect amount of lye the recipe called for. Their original recipe is extremely confusing as it provides instructions to make 3/8 of a cup of concentrated brown lye water, when the actual recipe calls for 3/4 of a cup! I hope this helps and you aren’t discouraged in your soap making 🙂

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Welcome! I’m Kathryn and I'm creating a tiny urban homestead in Portland, Oregon. Our 1/10th acre lot includes gardens, chickens, ducks, and rabbits. If you want to create an urban homestead please subscribe for email updates and let us help inspire you with baby steps to farming your backyard.
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