Articles Comments

Shepherds Hill Homestead » Heritage Skills, Making Lye Soap » Lye Soap Making

Lye Soap Making

      This page will show you how to make lye soap in an iron pot over an open fire.  It has a lot of pictures to help you get the picture of the process. If you do a search on the internet of soap making, you’ll see references to laboratory scales, exact temperatures and other discouraging terms. Let me begin by saying that your grandmother probably made soap just fine without these and you can, too!

   There is a legend that soap was discovered by the Romans on Mount Sapo. The legend goes that on the top of the mountain was an altar where animal sacrifices were taking place. Below was a stream where the Roman women did their laundry. They noticed some white flakes in the stream and found that the laundry got cleaner when the flakes were rubbed in.

Someone soon discovered that the rainwater came down and mixed with the ashes which produce lye. The lye broke down the animal fat and soap was being made. I don’t know if it’s true, but you’ll find references to soap in the Bible and note that the Lord uses ashes in Old Testament sacrifices for cleansing. (Numbers 19:9)

   The ingredients in this recipe are:

  • 2 gallons of non-tap water
  • 10 ounces of lye by volume and
  • 5 lbs of tallow (fat from beef)

If you use any other kind of fat except lard, you’ll have to change the amount of lye and vary the temperature. (see my notes regarding lard at the bottom of this page).

All soap is made with these 3 ingredients, even commercial soap. It is the basis of all soap. Some people see us at shows and say, “I’d never use that lye soap!”. They don’t realize that all soap is lye soap!

Below is a step by step diagram of how to make it.

First, render the fat out by cutting it into cubes about 1″ square. Trim off any part that looks like meat or isn’t white.

Cutting the Fat into cubes


It looks like potatoes cooking


When the fat is cooked down and you’ve gotten all the grease out of it, it’s time to strain out the solids. Make sure that you don’t burn the fat as the soap will not be as good. I use cheese cloth in a funnel shaped strainer. The picture shows it coming out as a beautiful amber color.

If you are beginning your batch with lard or tallow that is already rendered (i.e. you bought lard at the store in a tub) begin your soap at this stage.

Now, measure out 5 lbs of the liquid fat I have a stainless pitcher that just happened to hold half that amount so I just use 2 of them. Bathroom scales are sufficient for your measurement.  Put the fat in the iron pot and make sure that you have pure, clean liquid.


Next, add the water slowly into the fat. By adding it, you’ll cool it down and it will start to solidify. You always hear that oil and water don’t mix, but you’re about to make it happen!

The mix will start to turn into a greasy cream. Start your fire under the pot. I use small splits of pine. With these you can bring the heat up quickly if you want to and also you can control the heat better.

You’ll want to make sure that the mix looks blended. You don’t want to add the lye into it until it is. Let me stop and say that during this step, you’ll want to use some caution. First of all, Lye is an alkali and will burn your skin or eyes severely. Secondly, from this stage on, do not use any utensils that are aluminum as the lye will act like an acid to it. The below picture is what you’re looking for. It will look consistent and not show any separation of the oil.

Now measure out 10 ounces of lye. This is Red Devil Lye that is found in the grocery store along with drain openers. Yes, that’s what your Granny used, too! She may have used lye made from the ashes of hardwood fire, but it’s the same chemical. Powdered lye has been around since the 1700’s and is easier to get consistent soap from. You may have heard folks talk about lye soap that burns the skin, but if you accurately measure the same amount, you’ll get the same soap. Here, I use a glass jar that has the ounces labeled on it. Fill it to the 10 ounce mark and Sprinkle slowly and stir so that it all dissolves. I use a wooden paddle to mix.


You’ll notice that the saponification is already taking place! Look closely and note that soap bubbles are forming on the top of your liquid.


Now bring the fire up under the pot. You’ll want to cook the soap mixture from 30 minutes to an hour. Stir occasionally and keep it from boiling over. A slow boil is perfect.

Now, in the final stages it’s all a matter of sight. When you’ve cooked it a while it will look like very thick, creamy chicken soup. You will want to have your molds ready as the mix has to be poured up as soon as it comes together. We use old baking pans with Saran wrap in them to prevent sticking.

Note that soap is already forming on the edge!



Ok, here is the most important picture on the page! Notice that I’ve dipped my wooden paddle into the mix and it sheets off of it. You can click on the picture to enlarge. But don’t be fooled! Before it gets to this stage, it will look like it’s going to sheet but will still have a little clear drop if you wait a minute. Don’t pour if you see any clear liquid hanging with your icicles! It should look like hot wax that’s hardening off of the paddle. When you have sheeting like this, pull the fire away with a shovel and pour it up!

A soapmaker’s happiest moment!


Now you can pour it into molds. Once again, make sure that you don’t use aluminum. The soap will take at least a couple of days to harden enough to cut into bars. Even then it will be softer than the final product. It is usable as soon as it’s hard enough. It will probably take a week or so to really get hard.

See my  P.S. at the bottom regarding cure time.

A lot of people ask me what the cure time is on my soap. This soap has no real cure time. What they are referring to is when the lye content or Ph is down low enough to handle with your bare hands. Cold processed soap (soap done without a fire) has to be set up for several weeks before the lye is at a reasonable amount and it won’t burn your skin. This recipe allows the lye to break down and dissolve during the cooking. In fact, when I demonstrate this at shows, I clean my pot out bare handed as soon as the temperature is cool enough on the pot. It is an extremely mild soap and has never burned me chemically.

If you mix a base (Lye) and an acid together you get a neutral. Chemically, soap is a neutral and 7 would be perfect. But don’t worry if it’s not a 7. Just look at these!

  • Camay                9.5
  • Dial                      9.5
  • Dove                   7.0
  • Irish Spring       9.5
  • Ivory                   9.5
  • Lever 2000        9.0
  • Palmolive         10.0
  • Zest                     10.0

If you are using a cast iron pot as I do, make sure that you don’t put cold water in a hot pot. Wait to clean up until it’s cooled down. Cold water will crack the cast iron and ruin the pot. But once it’s cool, put water in it and simply wash it out. There will only be soap in it so it comes very clean! Don’t forget to wipe it dry and grease it down to prevent rusting.

This soap does not make a lot of suds as other soaps do. If you want suds, you can experiment with coconut oils. Also, a lot of folks have asked about adding herbs and things. If you want to put these in, add them in after the mix sheets and you’re about to pour. I leave my soap as basic and simple as possible. I get a lot of requests from deer hunters and people with allergies. The hunters like it because it doesn’t leave a smell on you and a lot of people have told me that their skin cleared up after using it. One final word-this recipe will also work using lard instead of tallow. It does take longer to cook, though. Normally, with lard you will have to cook it 3-5 hours. When it’s ready it looks more like clear hot-glue. Just look for the consistency to be the same (no separation).The soap is whiter and softer than the tallow soap but it does make more suds. Have fun making your soap! Don’t forget….

Granny did it, so can you!

P.S. (Paul says) there is NO CURE time on this soap as far as being safe to use. It does take a couple of days to harden enough to use and will continue hardening for a few weeks after that. This soap is safe to use right out of the pot. Cold processed soap (made without cooking) takes several weeks before it’s safe to handle.


Written by

Philippians 3:13-14 Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind, and reaching forth unto those things which are before,I press toward the mark for the prize of the high calling of God in Christ Jesus.

Filed under: Heritage Skills, Making Lye Soap

40 Responses to "Lye Soap Making"

  1. correll shea mayfield says:

    I’m so excited! I’m going to try this! Your directions are nice and detailed, to the point and not over zealous with too much information! Thank you! 😉

    1. brenda says:

      hello, we are a small homeschooling group out here in ky. we have had the blessings to make our first batch of soap. we made a lard soap it made 24 bars with 4.5lbs of lard and 1cup and a half of lye. ‘we also made another batch of coconut shortening and corn oil it looks kinda ugly brown but it smells great. we have 2 more weeks until the final cure. cannot wait. i did want to make a comment on the clean up i used the soap in the containers and it was so soft and it did not burn i was afraid at first but it left my hands nice and soft.
      good luck to ya all and it really woks.
      setvants in his name christ jesus.

  2. Christi says:

    Do you know how to do the cold process without all that measuring? That is what I am looking for. I might try this way as soon as my dh sees it though! He is such a big help.

    I would like to add coconut oil to it and also some fragrance oil to this hot process soap…do you know how to do that? Can you tell me?

    Do you think this is mild enough for a baby?


    1. paul paul says:

      I don’t have any experience with cold process soap-Sorry. I do know that there are recipes on the web for it but have never tried it. Paul

  3. Alicia says:

    What size cast-iron pot do you use for making the soap? I want to be sure I have a pot big enough for your recipe.

    1. paul paul says:

      I’ve never measured it but it’s over 10 gallons-

  4. amelia says:

    this is definitly the website im gonna gonna sell some too hopefully!!! im young and this is the kinda stuff that im into!!!

  5. Talon says:

    Thanks for the memories in the early 60’s I use to watch my grandmother make lye soap.. She would cut it into hand cakes

  6. Cindy DeLong says:

    Could you tell me if you can cook this inside the kitchen or would the fumes be to bad inside? Also how big a pot can you use to make this.

    1. paul paul says:

      If you attempt it in the kitchen make sure you use good ventilation when you add the lye. Run your fan for 3-5 minutes after adding it. After that the lye seems to be neutralized. You can adapt the recipe down to a smaller size if you wish. Just keep the proportions the same. The pot i use is 12-15 gallons and a double batch works in it.

  7. Missy Steiger says:

    I just received my lye yesterday and my girls and I plan on making soap for the first time when we take our break for Christmas. I was going to try cold process but your directions are so easy I can’t wait to try this. Thanks for the post!

  8. Todd says:

    I tried this over the weekend with lard. The only difference was I used a gas burner under our cast iron pot. I have two questions….
    1.) the soap turned out tan and not white or creamy. Could this be from over cooking or the old pot? It had not been used in years but was cleaned well before starting.
    2.) we cooked for about 3 hours and then all of a sudden the liquid turned to a mush. It was not pourable. I scooped it into the mold and have used it. I think its ok but was expecting a more gradual solidification. It went from a liquid to the mush in about 5 minutes. Was I cooking too hot? I used a slow boil… Any help would be appreciated.

    1. paul paul says:

      I’ll answer you directly Todd. It sounds like its ok though.

  9. Greg and Laura says:

    Hi Paul,

    Thank You for this great article. We can’t wait to give it a try.

    We are curious if a stainless steel or enameled pot (not cast iron) can be used.

    Greg and Laura

    1. paul paul says:

      Yes! Stainless or enamel ware works great with it. Try it out and see. I believe you will love the soap

  10. Kam says:


    I want to thank you so much for putting this out there.

    We made this soap this weekend with lard in a ceramic water bath caner, on a fish fryer outside, it cooked up perfect in about 2 1/2 hours. The instructions where wonderful. Yesterday, after it waxed up and got poured, had to be one of the more gratifying things we’ve even done. We’ve talked about making soap forever, but all the cold process soaps seemed confusing.

    I stumbled upon your site about two weeks ago, and decided to try soap making for real. It worked so well I just wanted to thank you.

    We rendered our own lard from our pigs, but after tasting it decided to use store bought for this soap. I’m never using Crisco again for cooking, real rendered lard is to tasty!!!

    One final word to anyone wanting to try soap, don’t trust a pressure caner to be stainless steal, we found out the hard way Presto caners are aluminum. Other than that, (our mistake) there were no snags in making soap with this recipe.

    Paul, one question though? We are wanting to make our own lye, if we used liquid lye as opposed to store bought, do you have an idea how much we would need by volume? Lye is really hard to find here, and not cheap. I’m wanting an ash hopper for Christmas.

    1. paul paul says:

      I am so glad that it worked out for you Kam! I haven’t made the lye from ashes but have studied it. The rule of thumb on lye water is that if you can float an egg it is strong enough. Other than that i am not sure how much you would need. If you make soap for a while it might be possible to pour the homemade lye water in and watch for the same kind of reaction of saponification. Let me know if you come up with a formula that works!

  11. Karen Anne says:

    hello –
    I am curious if you could share what the cause/solution to Todd’s soap questions were ((the color, texture…) I am wanting to make this with store bought lard too and would like to know so that if I have the same problem I can maybe fix it ahead of time?
    THanks so much!
    Karen Annw

    1. paul paul says:

      There are three things that can cause discoloration in soap.
      1) The most likely problem is a cast iron pot that has not been used in a while. I find that when my pot hasn’t been used in a while it makes soap that is slightly off white. The second batch is purer.
      2) If the lard or tallow is not fresh (has been sitting around in the heat) it will cause the soap to be yellow or brown.
      3) If the soap goes through rapid boiling it usually doesn’t cause a problem but it can if you have #2 (old lard)
      My experience has been that if soap forms solidly it is fine to use. It may not be aesthetically appealing but will still do it’s job.

  12. Karri says:

    Can the molds be plastic fishing lure cases

    1. paul paul says:

      Possibly-the ones I am familiar with would probably melt under the heat. If you do use those cool the soap down as much as you can and still get it to flow. Also, spray the cases with Pam or some type of oil..

  13. donna says:

    I have a wooden mold someone gave me. Its just simple 2×4’s nailed together. Do you think I still need to use saran wrap in it.
    Seems like it would be really easy to make molds with wood and make any size you wanted. Or, maybe wood doesn’t work too well…

    Love your web site and info.


    1. paul paul says:

      You can try a batch and see if it sticks. Minimally it probably could use a thin coat of Vaseline or spray oil like Pam.

  14. Todd says:

    Just to clarify, is the liquid cold or warm when you add the lye? We tried making soap this past weekend and were told to mix it in cold water, then add both the water/lye mixture to the oil. We already had a fire under the pot at this point. It was our first try and it did not turn out very well. It started to form chunks and we never could get it to melt into a syrupy mixture.

    1. paul paul says:

      The liquid is just warm enough to melt the fat when you add the lye. After you add the lye it will heat up a good bit. At the same time it will begin to turn soapy. It needs to cook at a slow boil for 1-3 hours.

      1. Kerrie from Georgia says:

        I remember as a child cooking lye soap with my aunt and grandmother both RIP. I remember bathing our dogs with the soap to kill the fleas and ticks and how well it worked.Thanks Paul you brought some great memories back. I’m going to be sure to keep this recipie close to home.

  15. donna h says:

    i made the second batch of soap today and it looks pretty good. the first never hardened- just stayed greasy. we made our own lye and i don’t think the first was strong enough. this batch of lye the egg floated with only a small amount of the top above water level.
    It did take a large amount of the lye water before the mix became creamy and sheeted. anxiously awaiting the cooling and curing of this new batch. thanks for you web site and clear instructions and information.

  16. Lane & Kelly Wise says:

    How big of a mold do we need for this recipe? How much soap will it make? We are going to try it; just trying to get everything together first. All we need is the mold. We love your site and are very thankful to have found it.

    1. Angelia Angelia says:

      I usually have at least 4 9×13 baking pans ready with plastic wrap. Sometimes the recipe will make 2 pans sometimes 4 and I honestly don’t know why that is. But I would have them ready for pour-up.

  17. Joshua says:

    I’m glad you mentioned the ashes. That’s the way my grandpa’s family made it. They would clean out the fireplace and burn only oak, put the ashes in a trough with a tiny crack, pour hot water in and let it seep through to make lye. If memory serves they also used hickory ashes to separate the husk from corn to make hominy. Keep up the good work.

  18. zo says:

    My grandmother made lye soap when I was small.I found a big bar that soap recentlyandwould like to divide it beween mcounsins. How would be the best do way to that? The soap is 50 years old.

    1. paul paul says:

      If you have some type of scroll saw or band saw I would suggest that. Cutting it with a knife is going to risk breaking it. if you must use a knife heat it up first-that might help. We cut our soap with a pastry cutter but a 50 year old bar is probably going to be pretty hard.

  19. Dayspringacres says:

    This Is Exactly What I Wanted To Know. I Want To Use My Crockpot, Add The Water, then The Lye. I Just Was Not Sure What Would Happen.S

  20. kenzie young says:

    Would the put be safe to eat out of after you make soap in it? I only have 1 cast iron pot. Thank you so much for this post!

    1. paul paul says:

      It probably would be due to the fact that families often had one pot to do soap, cracklins and hominy in. We don’t use ours for food but just soap. At minimum i would say to wash it thouroughly before using it for food.

  21. THERESA says:

    When you cook the fat down into lard do you put just the fat in the pan, or do you have a little water in the pan to start with?

    1. paul paul says:

      It’s just the fat-no water. Just make sure you keep it moving until enough grease cooks out of the fat or else it will stick to the pot. It’s a lot like stir frying.

  22. Lane & Kelly Wise says:

    Do you ever add anything to your soaps? Like essential oils. We were looking to try tea tree oil and wondering how much to add and when to add it.

    1. paul paul says:

      I rarely make scented soap but when I do the fragrance must be added just before it is poured. Otherwise it just cooks out of the soap. I hope that helps!

Leave a Reply




This site uses Akismet to reduce spam. Learn how your comment data is processed.