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Do you want to learn how to make soap from scratch? Cold process soap making method is what you’re looking for, friend! And I’m super excited to introduce you to soap making from scratch, with this ultimate guide to cold process soap making for beginners.
From tools and ingredients, to soap making science, safety, and common questions, this guide will walk you through everything you need to know about making soap from scratch, using the cold process soap making method.
A note before you read on: When you’re just beginning your research into making soap from scratch, it’s easy to get overwhelmed. As you read this guide, you may feel like there’s so much to learn, so many supplies you need to gather, so many safety rules to remember…
The whole soap making process seems daunting and you will wonder if you can even do it.
But I’m here to reassure you, you can do this!
I’d love to be your soap making mentor, so if you have any questions not answered here or you just need a bit of help, give me a holler by posting on my Facebook page or in the comment section at the end of this post.
How Do You Make Soap from Scratch?
Making soap from scratch, the “old-fashioned” way, is done by blending together:
- Liquid: water, goat’s milk, beer, etc.
- Oils or fats: coconut oil, olive oil, tallow, etc.
- A caustic: sodium hydroxide (AKA lye) for solid bar soap, potassium hydroxide (AKA caustic potash) for liquid soap
The liquid is first used to dissolve the lye. This lye solution is then blended with the oils to create soap.
A Little Soap Chemistry
When lye is mixed with oils, it triggers a chemical reaction called saponification.
Fat or oil molecules, called triglycerides, are made up of glycerin and fatty acids. When these molecules are mixed with a caustic (lye) the bonds holding the molecules together break, leaving you with glycerin and salts of fatty acids, or what we commonly call soap.
Saponification is the chemical act of turning a caustic, fats, or oils, into soap.
Without all of the modern conveniences that make soap making today much easier (like electric stove tops, and ingredients that can be bought rather than made) soap making was a long and arduous process.
Quick Soap Making History
Our foremothers and forefathers would typically make soap only once a year, cooking the water, oils, and lye made from wood ash together in a big vat over an open fire.
Wood ash lye (also called potassium lye) first had to be made by mixing hardwood ash with rainwater, allowing the lye to leach out over time. This lye water was captured in a bucket and collected to make soap.
Side note: If you’re super interested and want to get all the down-and-dirty details of making wood ash lye, this article by The Spruce Crafts is all about making lye from scratch.
But trust me, no need to go that far today. Lye is easily purchased; more on that in a bit.
Fats and oils also needed to be collected and prepared for soap making. Soap was made from whichever oils or fats were readily available.
In the U.S., soap was historically made from animal fats. Women would save all the fat from their meat, render it down into tallow which they saved up to make their soap. In other parts of the world, soap would often be made from vegetable oils, like olive oil.
Because they had no accurate way to measure the strength of their lye, old time soap was often very harsh and lye-heavy.
Today’s scratch-made soap is supremely gentle and good for your skin, thanks to modern tools, ingredients, and knowledge.
I imagine that our ancestors would be shocked to learn that today, we make soap just for fun!
And soap making is fun. It’s a chance to get creative as well as end up with a really gentle, luxurious, and useful product. A far cry from the old time soap the pioneers made.
What Is Cold Process Soap?
There are three different ways to make homemade soap from scratch. They are:
- Cold process soap method
- Hot process soap method
- Melt and pour soap method
The Hot Process Soap Method
Let’s take a look at the hot process method first, since this is the method that was historically used to make soap. In other words, the soap our ancestors made was made using the hot process method.
With the hot process method, the lye, liquid, and oils are cooked on the stove top until the saponification process (the process of turning oils and lye into soap) is complete.
Hot process soap making is so named because you use heat to make the soap. After cooking, the lye/water/oil mixture (or what soapers call the “soap batter”) is very thick, like mashed potatoes. This is because most of the water has evaporated out during the cooking process, leaving a pot full of not-quite-solid-yet soap.
The cooked soap batter is spooned and squished into a soap mold, left to cool and firm up for a day or so, then removed from the mold and sliced into bars.
The Cold Process Soap Method
The cold process soap method uses the same ingredients as hot process soap: lye, water, and oils. The difference is, with cold process soap the oils are initially heated to melt but the ingredients are not cooked further. They’re left “cold.”
Instead, after mixing the ingredients together they are poured into a soap mold and left alone. The saponification process happens in the mold without any extra help from us.
Some people call this method cold “press” soap, which is a misnomer and probably a misunderstanding of the word “process.”
Today, the cold process method is the most popular way to make soap from scratch.
It’s popularity is two-fold. First, you don’t have to babysit a cooking soap batter.
Secondly, cold process soap batter is quite fluid. If hot process soap batter is like mashed potato consistency, cold process soap batter is like pancake batter.
The thin batter of cold process soap is easy to work with, and allows the creation of gorgeous swirls.
Also, the end result gives you soap bars with a smooth, even consistency, unlike hot process which produces more craggy and rustic-looking finished soap bars.
After setting in the mold for 24 to 72 hours, the soap can be removed and cut into bars. Cold process soap bars are actually quite soft and sticky, similar to a soft cheese, when first unmolded. This is because they still contain lots of excess water.
Remember how the water evaporates out of hot process soap while cooking? With cold process soap the water evaporates out during a process called cure. (We’ll talk more about cure in just a bit, so keep reading.)
The Melt and Pour Soap Method
The last soap making method is also the simplest. With the melt and pour method, you aren’t making soap completely from scratch with oils, liquid, and lye. Instead, melt and pour soap making method uses a premade base that is melted down, to which you add your choice of color, fragrance, herbs, etc.
If cold process soap is akin to making a cake from scratch, melt and pour soap is like making a cake from a boxed mix.
The benefit to melt and pour soap making is you don’t have to handle lye yourself. The drawback is you technically aren’t making soap from “scratch” as the base is already made for you.
If you’d like to get more details about this soap making method, take a look at the Ultimate Beginners Guide to Making Soap Without Lye.
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Cold Process Soap Benefits
There are plenty of benefits to making your own cold process soap. Some of the biggies are:
You have complete control over the ingredients in your soap.
You can make 100% natural soap, eliminate synthetic ingredients, and avoid
any ingredients you’re allergic to. You can also tailor your soap to your specific taste in color, fragrance, and appearance.
Handmade soap is gentler than store-bought detergent bars.
When crafted properly, cold process soap is supremely gentle, and works well for those with sensitive or problem skin.
Handmade soap is more moisturizing than detergent bars.
Remember that when soap is made, salts of fatty acids and glycerin are created. It’s the glycerin that makes handmade soap so much more moisturizing than detergent bars or commercially-made soap.
You can save money over purchasing handcrafted soap.
If you’re already a handmade soap convert, you know that a good bar of handcrafted soap isn’t cheap, with most good bars costing between $6 and $12. You can make your own soap and save some cash.
One thing to realize, though, is you aren’t going to save money making your own soap if you’re currently buying inexpensive detergent bars for $.99. Your handmade soap will still cost more, but you’re comparing apples and oranges!
Compare the cost of your handmade bar to other what handcrafted soap is selling for to see the true cost savings.
It’s a fun craft that’s useful too.
If you’re a crafty or artistic person by nature, and you also like practical crafts, soap making is the hobby for you! I love that I can be creative and artistic and create something that is useful as well. And when you use it all up, you get to make more.
Drawbacks of Cold Process Soap Making
There are some drawbacks to making cold process soap. They are:
Your soap takes 30 days or longer before it’s ready to use.
Surprised? It’s true. Although you can make up a batch of soap in an hour or so, that batch of soap needs to cure for 30 days before use. (You’ll get all the info on why and how to cure your soap in just a bit.)
You have to handle lye.
I went back and forth deciding to call this a drawback, because you can handle lye safely and it’s really not as scary as it seems. But in some cases, handling lye really is a drawback—like if you have small children. It doesn’t have to be a deal breaker, you just have to be aware of and follow all lye safety guidelines.
Handmade soap bars dissolve away faster than store-bought detergent bars.
It’s the glycerin again! Glycerin in the soap bar attracts water from a humid bathroom air, or a wet soap dish, and can leave you with a gooey glop instead of a bar of soap if you’re not careful. Handmade soap must be kept dry between uses.
Certain colors, fragrances, and ingredients morph in cold process soap.
With melt and pour (and to a lesser extent hot process) when you add an ingredient you can be fairly certain it will do what you think it will do.
Due to the high pH of cold process soap batter, though, some ingredients can do weird things! Colors change completely, fragrances disappear into nothing, fresh ingredients turn a funky shade of brown or grey.
To avoid this, use soap dyes, colorants, and micas that have been tested and labeled for cold process soap use.
You can’t make a transparent soap with the cold process method.
The cold process method makes a lovely soap, but it’s always opaque. If you want a transparent soap you must use melt and pour, or a (fairly complex) variation of the hot process method.
The benefits of making your own luxurious handmade soap far outweigh the drawbacks.
Cold Process Soap Making Ingredients
Are you ready to dive deeper into the ingredients you need to make soap from scratch? You’ll need just a few simple ingredients to get started: water (or another liquid like goat milk), oils, and lye.
Oils and Fats
Oils make up the bulk of your handmade soap. When it comes to soap making, you can use nearly any oil or fat (animal or vegetable) that strikes your fancy.
When choosing oils, a good rule of thumb to remember: solid at room temperature oils (like coconut, palm, lard, or shea butter) will produce a harder finished bar of soap. Liquid oils (sweet almond, sunflower, olive) produce a softer bar.
Most soap recipes use a blend of solid and liquid oils to produce a bar that lathers well, is cleansing without being drying, and doesn’t melt away too quickly.
Oils that are considered soap-making staples are:
This oil makes a hard, white bar of soap that lathers exceptionally well, with big, fluffy bubbles. The majority of handmade soap contains some coconut oil.
Coconut oil can make your soap slightly drying to the skin, so it’s generally used along with other oils.
Palm also produces a hard bar of soap with lots of lather. It isn’t as drying to the skin as coconut oil can be. The drawback to this oil is that the agriculture and harvest of palm oil is endangering orangutan habitats. Many soapers eschew this oil because of this.
If you choose to use palm oil, a more environmentally-friendly option is to buy only responsibly-sourced palm oil, identified by the Roundtable of Sustainable Palm Oil (or RSPO) certification.
Olive oil makes an exceptionally mild and moisturizing bar of soap. Castile soap is traditionally an olive oil-only soap, but most soap makers blend olive oil with another oil.
Olive oil alone produces a low, creamy lather. But it produces a much softer bar, and one that needs a long cure time. Blending with another hard oil helps temper this.
P.S. Buy the cheap olive oil, it works just as well as the “good stuff” for making soap.
Castor oil, in my opinion, belongs in every handmade soap bar. It creates a fluffy, luscious lather that feels great on the skin. It also has skin conditioning properties.
You won’t need to use too much of this oil, though. Just 5% of the total oils will do, as too much can leave a sticky residue on the skin.
Lard or Tallow
Lard (from pork) and tallow (from beef) are very commonly used in soap making, even today. These animal fats make very hard, white, long-lasting bars of soap. Tallow especially creates big, fluffy lather. Lard soap lathers well, too, but some find the lather a bit slimy feeling. Blending it with another oil helps counteract this.
Besides the chief soap making oils, which make up the bulk of most soap recipes, you can also add specialty oils to your soap.
These oils are typically used in smaller quantities, because they are more expensive than the aforementioned oils. But they give your soap some added benefits.
Specialty oils often used in soap making include:
- Sweet almond: Conditioning, moisturizing, fluffy lather
- Sunflower: Conditioning, moisturizing, rich lather
- Shea butter: Moisturizing, can be a lather-inhibitor
- Cocoa butter: Moisturizing, makes a hard bar of soap
- Mango butter: Moisturizing, makes a hard bar of soap, creamy lather
- Apricot kernel: Gentle cleansing, moisturizing
- Avocado: Gentle cleansing, moisturizing
- Hemp: Gentle cleansing, creamy lather
Of course, these are just a few of the options you have. You can make soap with any type of oil imaginable (with the exception of mineral oil, baby oil, and the like. These are petroleum oils, not triglycerides, so you can’t turn these oils into soap.)
MY RECOMMENDATION: There’s no need to spend a ton of money on oils when you’re first starting out. You can get started making soap with just three oils:
With these three oils you can make a heck of a nice bar, and they’re relatively inexpensive. Once you’re feeling comfortable, you can branch out and start experimenting with other oils.
Sodium Hydroxide (AKA Lye)
Are you nervous about making soap from scratch because of they lye? Don’t worry, friend.
Although lye sounds scary, if you use some simple and common-sense safety precautions there is no reason to fear it. In all my years of soaping, I’ve never had a frightening incident with lye; I’ll venture to guess most soapers can say the same.
If you can use bleach or drain cleaner in your home safely, you can use lye safely too.
When choosing lye, you must only use 100% pure lye. Lye is often used as a drain cleaner (I know, yikes!) but it’s also used in the curing of olives and the manufacture of bagels.
While you can sometimes find lye at the hardware store, buying lye from a soap making supplier ensures you’re getting pure lye that is not adulterated with other harmful ingredients.
MY RECOMMENDATION: 100% Pure Lye from Essential Depot
Can You Make Soap from Scratch Without Lye?
No, soap cannot be made without lye. Lye is a necessary ingredient to turn oils into soap.
There is nothing you can substitute for lye in soap making.
While soap itself can’t be made without lye, there is a way to make soap without handling lye yourself. Remember the melt and pour soap method from earlier? The base has been made, with lye, by the manufacturer. All you have to do is cut it, melt it, and pour it into the mold.
The drawback to melt and pour soap is you don’t have complete control over the ingredients, and melt and pour soap bases are not 100% natural (although there are naturally-derived soap bases available.)
But I Don’t Want Lye In My Soap!
You can’t imagine rubbing anything with lye in it over your skin. Neither can I, actually.
Luckily, through the magic of chemistry, when cold process soap is made properly, you DO NOT have lye in the finished product. The oils, water, and lye have changed so that they are no longer oils, water and lye—it’s soap!
There is no lye left in properly made finished soap.
As long as you use a properly formulated, trusted recipe, your finished soap will not contain a trace of lye. (Read on and I’ll share some of my favorite, properly formulated soap recipes perfect for beginners.)
How To Safely Work with Lye
So now you’re committed to making your own soap from scratch, even though your a bit scared of the whole lye thing. That’s OK, friend! I was scared of making soap with lye the first time too.
I’m committed to helping you become comfortable handling lye and making soap from scratch. So, I’ve put together a series of posts to help you understand lye, its important role in soap making, and those all important lye safety rules.
Consider these articles REQUIRED READING before you make your first batch of soap:
- 8 Common Questions About Soap Making With Lye
- 7 Must-Know Lye Handling Safety Rules
- How To Neutralize Lye Spills When Making Soap
What Supplies Do I Need to Make Soap?
You will need several specific tools to build your soap making supply kit. Luckily, everything you need is easily found at your local big box store like Target or Walmart, or can be bought online.
One important note: All of the supplies must be used exclusively for soap making. Don’t reuse them for cooking.
This is especially true for the container that is used for the lye water solution.
Mark all of your soap supplies. I use a permanent marker and write SOAP on all of my soaping tools, and LYE on measuring cups and pitchers used for lye. That way an unsuspecting visitor won’t accidentally use my lye solution pitcher to mix up a batch of lemonade.
Alrighty, friend, so here are the soap making supplies you’re shopping for:
Eye Safety Glasses
First and foremost, you need to get yourself some safety equipment. Wear them the entire time you’re making soap, from beginning until after clean up. Don’t make soap without them!
Eye goggles protect your baby-blues (or browns, or greens, or hazels) from lye splashes and soap batter splatters. Buy something that you’ll be comfortable in, that fit well, don’t slip down your nose or squish into your cheeks, and won’t fog up.
Eye glasses won’t give you the same amount of protection; there are protective eye goggles that are designed to be worn over your glasses, so that you can both protect your eyes and see.
Gotta protect those hands too! I use nitrile exam gloves, because they’re thin and I can feel what I’m doing. If you’re allergic to latex, you can use these without problems.
Although I personally find them a bit clumsy and cumbersome, I know plenty of soap makers who love rubber dish washing gloves. The benefit of these is they are reusable; just wash your hands well with soap while you’re wearing them, rinse, remove, and let dry.
Large Stainless Steel Pot
This is what you will use to melt your oils and mix up your soap batter.
This pot must be stainless steel—absolutely no aluminum, cast iron, or non-stick (Teflon) coated pots. These elements react with lye, can throw off toxic fumes and curdle your soap batter.
Check the bottom of the pot. If it is stainless steel it will be marked by a stamp on the bottom. An 8-quart sized stainless steel pot is perfect for beginners, and will hold up to 5 lbs. of soap batter.
MY RECOMMENDATION: Cuisinart 8-quart stainless steel pot (I’ve had this workhorse for a decade-plus and it’s still perfect)
Stick Blender (AKA Immersion Blender)
Stick blenders are used to quickly and thoroughly emulsify your oils and lye solution together and bring to “trace” (a thickening of the soap batter and the beginning of the soap making chemical reaction.)
Yes, technically you can mix your oils and lye solution together by hand but it takes forevvvvvver to adequately emulsify. It can take more than an hour of constant stirring by hand for some soap recipes to come to trace, compared to 5 minutes or less with a stick blender. So, yeah, you’ll want a stick blender.
Also note that you can’t use a hand mixer or regular blender; it is dangerous to use these appliances to make soap.
Stick blender only, friend!
MY RECOMMENDATION: Kitchenaid 2-speed stick blender
Small Kitchen Scale
All soap making ingredients must be measured by WEIGHT (on a scale) and not by volume (in measuring cups). Weighing out your ingredients gives a more precise measurement than measuring by volume. And when working with lye, precision is important!
The ingredients in soap recipes are all listed by weight. You can’t use measuring cups instead, because weight measure and volume measure of oils are different. For example, 2 ounces of coconut oil by weight is NOT equal to 2 ounces of coconut oil by volume.
In order to get correct measurements, and to create a safe bar of soap that is not lye heavy, you must weight out all soap making ingredients.
Which means, you’ll need a scale. Small digital kitchen scales that weigh in both grams and ounces, and up to 5 lbs., are perfect. You can buy these in the kitchen gadget aisle of most big box stores, or get one online.
MY RECOMMENDATION: My Weigh KD-8000 Digital Scale
In this, you’ll dissolve the lye into the water. Lye water (also called lye solution) gets hot. As in, over 200 degrees Fahrenheit hot. So your lye water receptacle must be sturdy and heat safe.
I recommend a 2-quart sized, plastic #5 pitcher with a spout, for controlled pouring. Check the bottom of your pitcher, inside the little recycling symbol. That number should be 5. This type of plastic is very sturdy and can handle the heat of your lye solution.
If you have a pitcher with no number that you’d like to use, here’s a quick way to test it’s up to the task before you fill it with scalding lye water. Bring a pot of water to a boil. Set said pitcher down into your sink and pour the boiling water into it.
If your pitcher sags, warps, softens, or does anything other than sit there mightily holding that hot water, don’t use it for soap making.
Another note, don’t use a glass pitcher or container for lye water. Glass can shatter from the rapid temperature change that happens when water is mixed with lye. Lye can also etch the glass over time, making it more likely to shatter.
Lye water + broken shards of glass = no good, my soapy friend.
Plastic totally eliminates this problem. I’ve had some of my soap making pitchers for nearly a decade and they’re still going strong.
MY RECOMMENDATION: Rubbermaid 2-Quart pitchers (2-pack)
Plastic Measuring Cups with Spouts
But didn’t I just say not to measure your ingredients with measuring cups? You’ve got an A for paying attention! You will be using these to measuring your ingredients, but not by volume.
Instead, place these measuring cups on the scale and weight out ingredients into them. The handle and pour spout makes it easy to keep things neat and tidy.
You’ll need two of these, one for measuring out your oils and one for measuring out your lye. Remember, plastic only because lye can etch glass!
MY RECOMMENDATION: Measuring cups with spouts (3-piece set)
I love these for stirring lye water solution, scraping oils out of measuring cups, and getting every last bit of soap batter out of the pot and into the mold.
Silicone spatulas are sturdy and durable, and aren’t prone to soap making wear and tear like wooden spoons are. Plus, they’re cheap.
You’ll need at least two of these, one for mixing lye solution and one for oils/soap batter. But I can easily use five or six of these during one soap making session if I’m using lots of different colors in my soap (one spatula per color). So, having a few extra silicone spatulas on hand is a good idea.
MY RECOMMENDATION: Silicone spatulas (7-piece set)
There are many different types of soap molds available, and the mold you ultimately decide on depends on what you’d like your finished bars to look like and how much you want to invest in your soap mold.
Some of my favorite options:
Silicone Soap Molds
These are a breeze to use. No prep, just pour your soap in and pop out when it’s done. A favorite among soap makers is this 2 lb. size loaf soap mold.
Wooden Soap Molds
These are considered the gold standard in soap molds because they hold heat well and last forever. I’ve had the same wooden soap mold for 20-plus years and it’s still as perfect as day one. Those that come with silicone inserts are super easy to use.
Silicone Baking Trays
These make awesome soap molds! Since they’re using for baking, they can handle the high heat of your soap batter. Silicone muffin trays come in all types of fun shapes, while the silicone loaf pans and baking sheets make lovely loaf and slab molds.
Soaper’s tip: Place these molds on a sturdy cookie sheet prior to filling. This makes it easier to move your soap and less likely to spill.
You’ll not want to use any type of rigid clear plastic soap mold. These are meant for melt and pour soap only. They often can’t stand up to the heat of cold process soap.
Also, because cold process soap is soft and sticky for several weeks after it’s made, it is nearly impossible to unmold from rigid plastic molds.
(P.S. If you’re looking for frugal mold options, I’ve got some ideas for you in the section below, so keep reading!)
If you’re going to add fragrance or essential oils, color, oats, herbs, or other additives to your soap (and, of course you are, because that’s part of the FUN!) you’ll also need a few random supplies to add to your soap making kit:
- Small bowls for measuring minute amounts of additives
- Sturdy spoons for scooping out solid-at-room-temperature oils (like coconut oil or palm oil)
- Ladle for removing soap from pot and pouring into mold
- A soap cutter or a large non-serrated knife for cutting your soap into bars (or get this set with soap molds and cutters)
Ways to Save Money On Your Soap Making Supplies
Getting all of the supplies you need to make soap can be a bit of an investment when you’re first starting out, especially if you’re not sure you’re going to like making soap. (But… I’m pretty sure you’ll fall in love with it!)
But you don’t have to spend a ton of money in the beginning. Here are some inexpensive ways to get started making soap from scratch:
Ask friends and family if they have any of these supplies in their kitchen gathering dust.
This is an especially good way to score a stick blender. People often buy a stick blender (or are gifted one) use it once or twice, and stash it in the deep recesses of a kitchen cabinet and never use it again.
They may be glad to get rid of these unused items for just a few bucks or even give it to you in exchange for a few bars of your awesome, soon-to-be-made handcrafted soap.
Hit up garage sales and thrift stores.
I got my first stick blender at a thrift shop for $3. I can’t remember what I paid for my first soap pot, but I do know that I bought at a garage sale for less than $5. You can also find silicone baking trays, spoons, and spatulas.
These places are pure gold for inexpensive soap making supplies.
Shop your local dollar store.
All these years later, and I still get most of my soap making incidental tools at the dollar store. My local store always stocks #5 plastic pitchers, plastic measuring cups, silicone spatulas and spoons, EYE PROTECTIVE GOGGLES (Yes! Wrap-around type and everything!), skewers for doing swirl techniques, and tiny bowls perfect for measuring out fragrance or essential oils, colorant, and herbs.
You can nearly get all the supplies you need here, besides the pot, scale, and and stick blender. How’s that for one-stop shopping?
Repurpose boxes for soap molds.
Small boxes make lovely, inexpensive soap molds. So, start hoarding those old shoe boxes (or, if you’re an avid Amazon shopper like me, shipping boxes.)
Cold Process Soap Terms to Know
Ready to learn some soap making lingo? Here are a few key soap making terms that it’s important you understand, since you will regularly come across them in soap recipes and instructions.
As was mentioned before, saponification is the chemical process of turning liquid, lye, and oils into soap.
During saponification, the ingredients thicken and produce heat. Your soap batter will generate its own heat for several hours as it sets in the mold.
If you touch the outside of your mold several hours after pouring, you’ll notice that it’s as hot, or hotter, than when you first poured in the batter. Pretty cool.
Once saponification is complete, soap will gradually cool down and solidify. Saponification generally takes 24 hours to complete.
Saponification Values (or SAP Values)
The saponification value (also called SAP value) is the amount of lye needed, in ounces, to turn one ounce of oil into soap. Every oil has its own saponification value.
Here’s an example (hang on, friend, we’re going to do a wee bit of math):
Coconut oil has a saponification value of 0.191. That means it takes 0.191 ounces of lye to turn 1 ounce of coconut oil into soap. So, if you are using 10 ounces of coconut oil in your soap recipe you would need 1.91 ounces of lye to make soap (0.191 X 10 = 1.91).
Jojoba oil has a saponification value of 0.0695, so it takes 0.0695 ounces of lye to saponify 1 ounce of jojoba oil. For soap made with 10 ounces of jojoba oil, you would only need 0.695 ounces of lye (0.0695 X 10 = 0.695).
You can see, it takes almost three times as much lye to turn 10 ounces of coconut oil into soap than the equivalent amount of jojoba oil. Why is that?
Because every oil is made up of its own unique mix of triglycerides, they require a different amount of lye to properly convert those into soap.
Knowing the saponification value of each oil allows soap makers to calculate the perfect amount of lye needed for every recipe, and avoid the lye-heavy bars that were common in old time soap.
So, how do you know the saponification value of each oil? For that, you can refer to a saponification chart—a chart that lists individual oils along with their unique saponification value.
You can also plug your oils into an online lye calculator. You enter the amount of each oil you are using and the calculator computes the amount of lye you will need. There are several free lye calculators online, but the one that I use most often is Bramble Berry Lye Calculator.
Of course, when you’re first starting out you don’t have to formulate your own soap recipe right away. But knowing SAP value is important, even if you’re following someone else’s recipe, because it gives you a better understanding of how soap is made.
Superfat and Lye Discount
When you start looking deeper into saponification values of oils, you’ll notice something interesting: Different saponification charts list different SAP values for the same oil. How can that be?
The exact SAP value for any particular oil is the precise amount of lye needed to turn 1 ounce of said oil into soap. When using the exact SAP value there is no wiggle room; if there is even the slightest overage amount of lye, perhaps due to a small mismeasurement or a scale calibration that is a bit off, you will end up with lye in your finished soap bar. No one wants that!
So, what most saponification charts do a lye discount. They call for slightly less lye than is required.
Because there is less lye than is needed to turn the entire amount of oil into soap, some free oil (oil that is not turned into soap) remains in the finished bars. This extra oil is the superfat.
Superfat is measured in terms of percentages. So, if a soap is made with 7% superfat, that means 7% of the total amount of oil is left as free oil in the soap. Soap made with 10% superfat has 10% free oil.
Superfatting your soap does two things. First, the extra oil left in the bar makes your handmade soap extra moisturizing.
Secondly, and most importantly, creating your soap with a superfat gives some extra wiggle room when measuring lye, ensuring you will never end up with a lye-heavy bar even if there are slight mismeasurements.
For example, if you plan a 8% superfat for your soap, and there is a slight over-measurement of lye, you may end up with a 7% superfat soap instead. No big deal!
But, if you used the exact SAP value of your oils and there was a slight over-measurment of lye, you could end up with 1% extra lye in your finished bar. Big deal!
Circling back to why different saponification charts show different saponification values for the same oils: it depends on the lye discount, or superfat level, the particular chart is calling for.
Here’s a quick example:
- Olive oil SAP value = 0.14
- Olive oil SAP value with 5% superfat level = 0.13
- Olive oil SAP value with 10% superfat level = 0.12
So, depending on the superfat level of the particular SAP chart you are using, you will see slightly different SAP values for the oils. Most SAP charts will say the superfat level or lye discount they are using.
I recommend using a 6.5% superfat level (6.5% lye discount). This gives just enough free oil in the bar to be moisturizing while ensuring you have enough wiggle room to avoid lye heavy bars.
In every soap recipe, you’ll see a directive saying, “blend until trace.” Trace just means that the soap batter has begun to thicken. Once thickening starts, you know that saponification has begun!
There are stages to trace. The batter begins to thicken slightly, and continues to thicken until it turns into solid soap.
Some recipes call for blending to a specific stage of trace. Here’s a good reference:
- Light trace: The soap batter is a gravy or pancake batter consistency.
- Medium trace: Cake batter consistency
- Heavy trace: Pudding consistency
If the soap recipe you’re following doesn’t specify, you can just blend until the batter starts to noticeably thicken, or about medium trace.
As you gain experience you will find your own personal “sweet spot” where you like to get your soap batter before pouring. I pour my batter between medium and heavy trace. Other soap makers who do intricate, fluid swirls pour at a very light trace.
It’s also important to know that certain recipes come to trace faster than others. Soap recipes with high amounts of olive oil, for example, take a lot of blending to come to trace. Recipes with high amounts of solid oils with trace much more quickly.
Some fragrance oils can make your soap batter trace within seconds; this is called acceleration. So, if you see a fragrance oil that says “accelerates trace,” you’ll want to blend to just light trace and work quickly to get it into the mold. Other ingredients that can make your soap trace faster are clays and oatmeal.
Can You Substitute Oils in Cold Process Soap?
Say you’ve found a soap recipe you’re excited to try, but it calls for sunflower oil which you don’t have on hand. Is it OK to substitute another oil?
Remember, each oil has its own saponification value, which determines the specific amount of lye needed in each recipe. If you simply swap oils, you can easily end up with the incorrect amount of lye.
You can’t substitute oils in any cold process soap recipe, unless you also recalculate the amount of lye needed.
Another thing to remember is the oils in every soap recipe is chosen for a specific reason, in order to make a bar that is cleansing with good lather, but still moisturizing and conditioning to the skin. Substituting one oil for another can leave you with a bar that isn’t balanced.
When you are a beginner, I highly recommend following recipes exactly and avoiding substitutions.
Once you have more experience, you can experiment with substituting oils. Until then, either buy the oils you need, or choose a recipe that works with the ingredients you have on hand.
Beginning soap makers typically have lots of questions about cure, but honestly curing your soap is super simple. Here’s what you need to know:
How do you cure soap?
To cure soap, simply set the bars on brown paper or butcher paper and place in an out of the way spot like a closet or shelf. Turn the bars once every week or so to expose all sides to air. You do not need to wear gloves to turn your soap at this point. It’s safe to touch with bare fingers.
How long does it take to cure soap?
Most soap takes 30 days to cure. But certain soap recipes, like those that contain lots of olive oil or goat milk, for example, can take 60 days or longer. If your soap still feels soft, squishy, or sticky after 30 days, let it set for two more weeks and try it again.
Why does soap need to cure?
When you unmold your soap it will be soft and sticky, similar to a soft cheese. The curing process allows the excess water within the bar to evaporate away, creating hard bars that are ready to use.
Can you make soap cure faster?
Unfortunately, no. Although some soap makers claim you can speed cure by placing a fan to blow over your bars, or putting the soap in the oven on low, helps speed curing research has shown otherwise. Time is the only way to fully cure soap.
Can you use soap without curing?
Technically, soap is safe to use before cure. Saponification is complete after about 24 hours, which means the soap is no longer caustic. It won’t be very pleasant to use before curing, though, because the bar will be super soft and slimy, won’t lather well, and will melt away really fast. A good cure improves your soap immensely.
Cold Process Soap Recipes
One of the absolute most important thing you can do when you are a beginning soap maker: only use trusted, tried-and-true cold process soap recipes.
If the recipe you’re using is a stinker, here are some of the problems you can run into:
- Ratios of oils are off, creating a bar that is either too soft, too drying, doesn’t lather well, or melts away too quickly.
- Too little lye in the recipe, leaving you with mushy, oily goop rather than soap.
- Too much lye in the recipe, which is the most worrisome of the bunch because it leaves you with lye in your finished soap bar. This can cause major skin irritation and/or eye injury.
But when you’re first starting out you don’t have the experience to know, just by looking at the recipe, whether it’s a good one or not. So what’s a beginning soap maker to do?
If you’re choosing cold process soap recipes off the internet, I highly suggest running it through a lye calculator first.
You just enter in the amount of each specific oil in the recipe. The calculator will determine the amount of lye needed for that recipe.
The amount of lye the calculator suggests needn’t be exactly the amount called for in the recipe, but it should be very close.
Lye measurements may be a bit different depending on the superfat of the recipe compared to how the calculator computes.
So, if the recipe calls for 4.8 oz. of lye, and the calculator figures 5 oz. of lye, you’re in the right ballpark. If there is just a few tenths of a difference between the two, your recipe is OK as-is.
But, if the recipe calls for 7 oz. of lye and the calculator says to use 5 oz., that’s a considerable difference! If this is the case, follow the lye calculator.
Typos or miscalculations happen, even in recipes from trusted sites. This is why I always recommend doing a double-check of lye amounts with any recipe
MY RECOMMENDATION: Bramble Berry’s Online Lye Calculator
Basic Cold Process Soap Making Instructions
My goodness, friend, you made it through all of the soap making basics… so are you ready to get your hands dirty (or, uhh, clean?) and actually make some soap?
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I hope this Cold Process Soap Making for Beginners Guide was helpful. Happy Soaping!