Handmade or homemade lye soap (All natural soap must be made with lye, but don’t worry, none is left in the soap) is a great way to be in control of what is going on your family’s skin and thus, into their bodies.
When I first looked into soap making, I felt like I had information overload. It took me a while of reading about it before I decided I was ready to make my first batch.
Information is here, there, and everywhere, but not much of it is as detailed or step by step as I would have liked. Now, years later, I’m super glad to be able to put together these 7 Easy Steps to Homemade Lye Soap for Beginners. It may seem difficult at first, but once you do it once or twice, you’ll realize that it’s really not that big of a deal…and can be super addicting.
Of course you can always try 100% Natural Soap bars from my Shop as well.
How to Make Homemade Lye Soap
Before we get started, I wanted to let you know that I have 2 paperback soap making books available in book stores.
Natural Soap Making Book for Beginners – cold process, natural coloring, herbs, hot process and melt and pour explained, plus so much more. VERY thorough.
Easy Soap Making – melt and pour and hand-milling, with some cold process. Simple recipes and steps.
- Weigh and melt your fats in a large pot.
- Weigh the lye in a zip close bag and weigh your water into a plastic container. Go OUTSIDE and slowly pour lye into container of weighed water and stir with stainless steel spoon. Important!!! Don’t pour the water into the lye. Pour the lye into the water (more below)
- Prepare mold (add wax paper if necessary)
- Weigh essential oils according to recipe, set aside.
- When fats and lye both reach about 100° F, pour lye into pot of oil and stir.
- Use blender on 5 minutes, stir by hand 5 minutes, etc. on and off until trace.
- Add essential oils and any natural coloring agents or textures, stir very well.
- Pour into mold and incubate for 24 hours.
- Remove from mold and cut.
- Let air out and harden. Use after 4-6 weeks.
Big Tip: Think of your ingredients in 3 categories
- Fats and oils. These go in one pot. These are things like lard (pork fat) or tallow (beef fat), coconut oil, olive oil, and palm oil. I don’t like to use crisco or vegetable oil because of their soy content, pesticide residue, and preservatives.
- Lye crystals and water. These will be combined to make “lye water” in a separate dish from your fats and oils. If you are trying a milk recipe you will often add it here in place of some of the water.
- Essential oils and other Ingredients. These will be added at the last-minute for smell, color, or texture. This also includes honey and salts.
You will need the following items:
- Stainless steel pot (no iron or aluminum)
- Stainless steel spoon
- Plastic spatula
- Hand mixer. A stick blender helps it come to trace faster.
- Zip close bag
- Bowls to measure oils
- Container dedicated to lye water (I use an old plastic container)
- Digital scale that weighs in ounces to the tenths place (e.g. 2.3oz)
- Thermometer (a cheap candy thermometer works fine)
- Mold to pour soap in
- Wax paper to line mold if necessary
- Towels for incubating mold.
7 Easy Steps to Homemade Lye Soap for Beginners
Step #1: Fats and Oils
Different fats add different qualities to your soap. For example, coconut oil will help create a lather, while castor oil is great for bubbles. For a great outline of oils and their uses in soap (and all kinds of other great info.), see this website: Soap Making Essentials. The first thing you need to know if you’ve never made soap is that your ingredients are weighed, not measured. And they need to be precise! Of course, the smaller the batch, the more precise you need to be. I purchased a relatively cheap digital scale (like this one) that lets you set your bowl on the scale and reset it to zero so that you are only measuring the ingredients and not the bowl (less math). Use a rubber spatula to scrape all the little bits into your large stainless steel pot. Be precise.
Step #2: Lye and Water
Where to Get it:
I searched and searched for lye at a local store. Apparently it’s also used for making some type of illegal drug as well, so a few people gave me weird looks and asked why I wanted it. Really? Anyway, I found it in the plumbing section of an Ace Hardware store for a little over $3 for 16 oz. You have to get the pure crystals, not some liquid concoction! If you don’t want to search everywhere you can get some on Amazon.
What is It:
Lye’s real name is sodium hydroxide. It is originally derived from ash (We can easily gather a different form that makes a softer soap called potassium hydroxide or potash from firewood ashes).
It will react with water. The chemical reaction produces an invisible gas and heat! Blasting your lye water mixture to a whopping 200 degrees F, depending on your starting water temperature.
How to Use it:
I measure the lye into a plastic bag and the water into a medium sized plastic container. This way I remember to pour the lye into the water and not the other way around. If you pour water into lye, the lye to water ratio is so high that the lye can explode (so I’ve read…and I don’t want to test it). I go outside and pour the lye into the water and stir. I even did this in a snow storm once (I should have taken a picture).
Once the lye is dissolved there are no more fumes. This only takes about a minute (I usually stir while holding my breath and then run away). After it is all dissolved you can take it inside very carefully. If it gets on your skin it will feel itchy long before you notice the damage it is doing. It will burn your skin if you don’t wash it off.
Lye also reacts with aluminum and iron. Do not use utensils with those ingredients or the lye will slowly eat away at them. Use stainless steel, plastic, or glass.
I recommend using safety glasses, a long sleeve shirt, gloves, and a mouth mask. This may seem silly, but the first time I made soap I didn’t have any of these things. Let’s just say, when you breathe in lye fumes it literally takes your breath away. Also, later when you blend the lye with the oils some tiny bits can splash up onto your arms and begin to burn you. Don’t be scared though! Just keep the kids out of the kitchen and treat it like you would bleach – you don’t want it on you.
Temperatures are important! After all, you want a chemical reaction to occur. The fat molecules need to be blasted open by the lye molecules, converting both molecules into soap.
You will have to heat up your fats in order to get them up to around 100F degrees or to melt the hard fats. I try to have my oil AND lye right under 100F (95-100) before I add the lye water to the fats.
It can be a bit of a juggle to get both your lye water and your fats/oils to the same temperature. If one is cooling faster than the other, just give it a cold water bath by running some cold water in your sink and placing your pot or plastic container in it. If one is cooling down too fast, then cover it or pace it in a hot bath so it stops cooling. Be precise and you won’t have to guess about what went wrong. Instead, the only thing you’ll have to worry about is if it’s ready to pour yet or not.
Step #4: Trace
Trace is what it is called when the soap is ready to pour into the mold. It leaves a “trace” behind on the top of the mixture. You will usually see the soap turn a creamy color and will feel it get thicker as you stir. Use your big spoon to drizzle a little on top of the mixture. If it sinks right in, then it’s not ready (Though, the first batch I made never left a trace that I could see and I thought it was not going to set. It set up beautifully. Now I know that’s how Castille Soap often behaves.). If you look at it with the light reflecting off of it and you can see the drizzle leave a little path on the top, then it has gotten to light trace. If it starts to become like thick pudding then it is at full trace and needs to be poured quickly! You don’t want it setting up in your pot.
Step #5: Essential Oils
As recipes get more complicated, there are more things that might be added in at the last minute. This is after you combine the lye water with your fats, it has come to trace, and it is ready to pour into the mold. If you want true oils and not synthetic chemically made smells, stick to Essential Oils. For more information on the differences see my article on Essential Oils vs Fragrance Oils.
Most recipes will give you the amount of Essential Oils to add that’s good for that size batch. Though, this can vary depending on the essential oil since some are more potent than others. Use it as a guideline and then after you stir it in see if you can smell it. I don’t like my soap to have a strong scent, but others do. Use what you like!
Step #6: Pour and Incubate
You have to have something to put it in for it to set up. Want some frugal ideas?
You can use:
- a plastic container, but I had a hard time finding one that wasn’t rounded or ridged on the bottom or sides.
- a cardboard box
- glass container, but these are harder to get your soap out of (I don’t care what people claim about putting it in the freezer)
- PVC pipe – nice round soap
- Pringles cans – peel off the outside when it sets.
- Small wooden planter
- Make a wooden mold
- Buy a Wooden Mold
- Buy silicone molds
I was worried about getting my soap out of my plastic container that I used with my first batch and I lined it with plastic wrap. I’ve seen pictures where people have done this. It did not work out well! Even though I tried to get out all the wrinkles, I apparently did not and it was folded into the soap where if I pulled, it tore and was stuck into the soap a little. It also made tons of wrinkles! My favorite liner? Wax Paper!! Works great!
So, once you’ve lined your mold with wax paper (if necessary) and poured your soap into it. Give it a slight jiggle to make sure it’s all settled evenly. You’ll want to place it on a very even surface for the first 24 hours or you will have crooked soap.
Cover in towels to help keep the heat in (remember that chemical process). Obviously, I use less towels in the summer and more in the winter. Below is a picture of my soap box in a plastic container in the winter. Yes, my house is freezing during the winter!! In the summer I just drape 2 towels over the box.
Soap needs to be incubated for a 24 hour period. After it is poured into a mold, place on a blanket (or towel if it is a small batch), and place blankets all around it. After the 24-48 hour period check to see if it is set. If set, you can take your soap out of the mold and cut.
#7 Curing and Storing
Lye soap is not ready to use at once. The lye has not finished converting the oil molecules into soap molecules. If you use it right away, it may quite possibly burn your skin. The longer it sets the more mild it will get, the harder it will get, and the longer it will last. I heard it compared to cow manure once; it stays hot because of the decomposition of its contents, but give it enough time and it will become as mild as good dirt. So, cut your soap and let it cure for 4-6 weeks, turning occasionally so that all sides dry out.
Where to put it?
The only downfall is that over time your essential oils will grow fainter, but I’m talking a few years or so before you may notice a difference. One idea is to use a plastic storage bin with drawers like this one. This way, you can semi cover them, but leave the drawer cracked open a bit for ventilation while they continue to cure. You don’t want to leave them where there may be too much moisture and they will end up with mold over time. A nice cool dry place is great.
Need Recipes? Check out my Homemade Soap Page for lots of great resources!