What Makes Soap, Soap? Inside the Art & Science of Cold-Process Soapmaking
Vol. 1, Article 8
Know What’s in Your Bar.
There is something wonderfully simple about a bar of handmade soap.
Pick it up. Add water. Work up a lather. Wash. Rinse.
But what happened before that bar reached your sink is anything but simple.
There is chemistry involved. Formulation. Ingredient selection. Measuring. Mixing. Temperature. Saponification. Cutting. Curing. And, in our case, years of experience making the same original family recipe we've trusted since 2015.
At Mammy's Soap Co., we don't begin with a premade bar and simply add fragrance.
We make true cold-process soap from scratch.
Quality oils and butters.
Sodium hydroxide.
Carefully selected ingredients.
No added synthetic detergents. Ever.
Every loaf is made in a small batch of just 20 bars, and every bar is allowed to cure for a minimum of four weeks before it is ready for you.
So this week, we're taking you behind the scenes.
What actually makes soap...soap?
What's the difference between traditional soap and many of the cleansing bars at the grocery store?
Why do we sometimes use goat milk, coconut milk or aloe vera juice?
Are essential oils always better than fragrance oils?
What about natural colorants versus mica?
And perhaps the question we've heard more than any other:
“If soap is made with lye, is there still lye in my finished bar?”
Let's talk soap.
Key Takeaways
Here's what we want you to know before we get started:
- Traditional soap is created when fats or oils react with an alkali such as sodium hydroxide.
- This chemical reaction is called saponification.
- Properly made soap is a new product—not simply a mixture of lye and oils.
- Glycerin is naturally created during the soapmaking reaction and remains part of our cold-process bars.
- Not every solid cleansing bar sold at the store meets the regulatory definition of traditional soap.
- Different liquids and additives, such as goat milk, coconut milk and aloe vera juice, can change how a soap is formulated and the characteristics of the finished bar.
- Essential oils and fragrance oils are different, but “natural” does not automatically mean better or safer.
- Proper curing is an important part of cold-process soapmaking.
- Mammy's Soap Co. makes every loaf in a 20-bar small batch and cures every bar for a minimum of four weeks.
- We've been making our original family soap recipe since 2015.
- Mammy is a Certified Advanced Soapmaker through the Handcrafted Soap & Cosmetic Guild.
1. First Things First: What Is True Soap?
Let's start with chemistry.
Traditional soap begins with two major components:
Fats or oils + an alkali
For the hard bars we make at Mammy's Soap Co., that alkali is sodium hydroxide, commonly called lye.
Oils and butters contain fats made largely of molecules called triglycerides. When properly calculated amounts of those fats and sodium hydroxide are combined, a chemical reaction takes place.
It's called:
SAPONIFICATION
During saponification, the starting materials are chemically transformed, producing soap—the sodium salts of fatty acids—and glycerin.
In its simplest customer-friendly form:
OILS + ALKALI → SOAP + GLYCERIN
This is an important distinction.
We aren't simply stirring lye into oil and putting that mixture into a package.
We're creating a chemical reaction that produces something new.
The FDA describes ordinary soap as being made by combining fats or oils with an alkali such as lye. Under its regulatory definition, true soap consists principally of alkali salts of fatty acids and gets its cleansing action from those soap compounds.
That is traditional soapmaking.
And it's what we do.
2. “Wait...You Put Lye in Soap?”
We do.
And this is one of our favorite soapmaking questions because it gives us the opportunity to explain just how fascinating the process really is.
You cannot make traditional soap without an alkali.
For our cold-process bar soap, that alkali is sodium hydroxide.
But remember what we just learned about saponification.
The sodium hydroxide doesn't simply sit inside the bar unchanged beside the oils.
It reacts with the fats.
The FDA specifically notes that when traditional soap is properly made, no lye remains in the finished product.
That's why formulation matters so much.
A soapmaker needs to understand the oils and butters being used, calculate the appropriate amount of sodium hydroxide, accurately weigh ingredients and understand the chemistry taking place inside that soap mold.
Which brings us to something very important to us...
3. More Than a Recipe: Education Matters
Cold-process soapmaking is both art and science.
Knowing how to make soap means understanding more than how to follow a list of ingredients.
A knowledgeable soapmaker needs to understand formulation, oils and fatty-acid profiles, alkali calculations, additives, colorants, fragrances, troubleshooting, saponification and finished-bar evaluation.
That's one reason we're proud that:
Mammy is a Certified Advanced Soapmaker through the Handcrafted Soap & Cosmetic Guild.
The HSCG's Advanced Cold Process/Hot Process Soapmaker certification assesses higher-level knowledge of soapmaking chemistry and terminology, formulation, testing, evaluation, troubleshooting, additives and colorants. Candidates also formulate and submit soap for evaluation.
For us, that education matters.
Because when we're making something that your family will use every day, we believe understanding why the process works matters just as much as knowing how to make a beautiful bar.
And while we've continued learning over the years, we've remained rooted in the recipe that started it all.
Our original family recipe.
Made since 2015.
4. What Does “Cold Process” Actually Mean?
Cold process is a traditional method of making soap from scratch.
At Mammy's Soap Co., the process begins by selecting and carefully measuring our ingredients.
We use quality oils and butters as the foundation of our original family recipe.
The sodium hydroxide solution is carefully prepared.
The oils and butters are prepared.
Then the two are combined under controlled conditions.
As we mix, the soap begins to emulsify and eventually reaches what soapmakers call trace—a stage where the mixture has emulsified and begun to thicken.
Depending on the particular soap we're making, this is also when carefully selected fragrance, colorants or other ingredients may become part of the batch.
Then it's poured into the mold.
And something amazing continues happening inside.
Saponification.
The mixture transforms into soap.
After the appropriate time in the mold, the loaf is removed and cut.
And at Mammy's Soap Co., every loaf becomes just:
20 BARS.
Not hundreds.
Twenty.
Then those bars begin another very important part of their journey.
They wait.
5. Why Does Our Soap Cure for at Least Four Weeks?
Cutting a beautiful loaf of soap doesn't mean it's ready for your shower.
At Mammy's Soap Co.:
EVERY BAR CURES FOR A MINIMUM OF FOUR WEEKS.
During cure, water gradually evaporates from the soap.
As the bar loses water, it generally becomes harder and longer-lasting in use. Cure also allows the finished characteristics of the bar to develop.
This isn't a part of our process we rush.
We make it.
We unmold it.
We cut it.
Then we give it time.
A minimum of four weeks. Every bar.
There's something we love about that in a world where nearly everything is designed to happen faster.
Some things are simply worth waiting for.
6. Where Does the Glycerin Come From?
Here's another fascinating part of traditional soapmaking:
We don't have to add glycerin to create it.
Glycerin—also called glycerol—is produced as part of the saponification reaction itself.
Remember:
OILS + ALKALI → SOAP + GLYCERIN
That naturally produced glycerin remains part of our cold-process soap.
This is also one reason it's important to understand the difference between a traditional handmade soap bar and every other solid cleansing bar sitting on a store shelf.
They may look similar.
Chemically, they may be quite different.
7. Is Every Bar at the Grocery Store Actually Soap?
Here's where things get interesting.
Consumers commonly use the word soap to describe almost any solid bar used for washing.
Regulatorily and chemically, however, not every cleansing bar is traditional soap.
According to the FDA, for a product to meet its regulatory definition of soap, its nonvolatile portion must consist principally of alkali salts of fatty acids, and those soap compounds must provide its cleansing action. Products that use synthetic detergents for cleansing don't meet that particular definition, even though consumers may still see the word “soap” used in the marketplace.
That's why you may also encounter terms such as:
Beauty bar
Cleansing bar
Syndet bar
or other cleanser descriptions.
Brands such as Dove, Dial and Irish Spring offer numerous products and formulations, and those formulas can change, so we don't believe in making sweeping claims about every bar made by another company.
Instead, we encourage you to do something much more useful:
READ THE INGREDIENT LABEL.
Ask:
What is actually doing the cleansing?
Is this traditional soap?
Does it contain synthetic surfactants or detergents?
What ingredients are being used?
Knowing what you're buying gives you the ability to make the choice that fits your family.
Know what's in your bar.
8. What About Glycerin in Commercial Products?
You may have heard the statement:
“Commercial soap has all of its glycerin removed.”
The reality is more nuanced.
Manufacturing methods and formulations differ among companies and products. Glycerin may be removed during some commercial soapmaking processes, retained, or included in a formulation in other ways.
So we don't need to make a blanket statement about every commercial bar.
We can tell you exactly what happens with ours:
The glycerin naturally produced during our cold-process soapmaking remains in our bars.
We aren't separating it out as part of an industrial soap-refining process.
It's part of the soap we make.
9. Why Add Goat Milk, Coconut Milk or Aloe Vera Juice?
Once you understand the basic chemistry, soapmaking gets even more interesting.
Water is commonly used to prepare the sodium hydroxide solution, but soapmakers can formulate recipes using other liquids or use them as part of the liquid portion of a recipe.
That's where ingredients such as these come in.
Goat Milk
Goat milk brings its own combination of fats, sugars and other naturally occurring components into a soap formulation.
Milk soaps also require knowledgeable handling because the sugars and proteins in milk respond differently to the heat generated during soapmaking.
Coconut Milk
Coconut milk contains fats and naturally occurring sugars and can be incorporated into soap formulations to create a different bar experience and formulation than simply using water.
Aloe Vera Juice
Aloe vera juice can replace some or all of the water portion in certain soap formulations.
Again, this isn't simply about putting an ingredient name on the label.
Changing the liquid can change how the soap behaves while we're making it, which is why formulation and soapmaking knowledge matter.
Different recipes have different purposes.
And that's part of the craft.
10. Essential Oils vs. Fragrance Oils: What's the Difference?
Let's clear up another common misconception:
Essential oil does not automatically mean “good.”
Fragrance oil does not automatically mean “bad.”
They're different materials.
Essential Oils
Essential oils are concentrated aromatic materials obtained from plant sources through processes such as steam distillation or expression, depending on the particular plant and oil.
We use quality essential oils in soaps where they are appropriate for the fragrance and formulation.
But essential oils have their own usage considerations and limitations.
They aren't appropriate at unlimited concentrations simply because they come from plants.
Natural still requires knowledgeable formulation.
Fragrance Oils
Fragrance oils are formulated aromatic blends.
They allow soapmakers to create fragrances that may be difficult—or impossible—to obtain using essential oils alone.
Think of scents inspired by foods, complex fragrance combinations and many seasonal aromas.
At Mammy's Soap Co., when we choose fragrance oils, our standard is clear:
Our fragrance oils are always phthalate- and paraben-free.
We carefully select the fragrance materials we use rather than assuming that one entire fragrance category is automatically good or bad.
Because what matters is what you're using, its quality and how it's being used.
11. Natural Colorants vs. Micas
Fragrance isn't the only creative choice a soapmaker makes.
There's also color.
Cold-process soap has a high-pH environment during production, and not every colorant behaves the way you might expect once it goes through soapmaking.
Natural Colorants
Depending on the recipe and desired result, soapmakers may use ingredients such as clays, charcoal, botanicals and other suitable colorants to create naturally inspired colors.
Natural colorants can produce beautiful earthy tones, but they can also behave less predictably.
Micas
Mica-based soap colorants allow soapmakers to create a wider and often more predictable range of colors.
Depending on the specific colorant, mica products may use natural or synthetic mica combined with approved pigments or color additives.
And here's another misconception worth clearing up:
“Mica” does not automatically mean “bad.”
Just as with fragrance, what matters is understanding the specific material, its source, its suitability for the intended application and how it is used.
Sometimes we want the earthy character of a natural colorant.
Sometimes a design calls for the consistency and color possibilities of mica.
That's where the art joins the science.
12. So Why Choose True Cold-Process Soap?
We don't believe we need to frighten you away from another product to explain why we're proud of ours.
We can simply tell you what you're getting.
When you choose a Mammy's Soap Co. cold-process bar, you're choosing soap made from scratch through traditional saponification.
You're choosing a bar made with:
Quality oils and butters
Naturally produced glycerin retained in the bar
No added synthetic detergents—ever
Carefully selected essential oils and/or phthalate- and paraben-free fragrance oils
Thoughtfully selected colorants
Small-batch production
A minimum four-week cure
And you're choosing soap made by people who understand what's happening inside the soap pot.
That's enough for us.
13. How Long Should a Handmade Bar of Soap Last?
Here's the answer customers sometimes don't expect:
It depends.
The lifespan of a handmade soap bar is affected by:
- The formulation and size of the bar
- How frequently you use it
- How many people use it
- Whether you're using it directly on the body or with a washcloth
- How much water it encounters
- Most importantly, how you store it between uses
One of the fastest ways to shorten the life of a beautiful handmade bar is to leave it sitting in water.
Help Your Handmade Soap Last Longer
Use a well-draining soap dish.
Allow air to circulate around the bar.
Keep it out of standing water.
When possible, don't store it directly beneath a constant shower stream.
Let it dry between uses.
That little bit of care can make a noticeable difference in how your bar performs and how long you get to enjoy it.
14. Twenty Bars at a Time. Since 2015.
This is where chemistry becomes personal for us.
Mammy's Soap Co. has been using our original family cold-process soap recipe since 2015.
Over the years, we've learned.
We've studied.
We've formulated.
We've experimented with fragrances, additives, colors and designs.
Mammy became a Certified Advanced Soapmaker through the Handcrafted Soap & Cosmetic Guild, whose advanced certification evaluates soapmaking knowledge and practical competency.
But the heart of what we do has remained remarkably simple.
Quality oils and butters.
No added detergents. Ever.
True cold-process soap.
Small batches.
Twenty bars in every loaf.
A minimum four-week cure.
Our original family recipe since 2015.
There are faster ways to manufacture cleansing bars.
There are bigger ways to manufacture them.
But this is our way.
Twenty bars at a time.
Build Your Wellness Routine
We talk a lot in the Wellness Journal about building simple routines.
And soap is one of the simplest routines you have.
You reach for it every day.
Maybe several times a day.
So this week's routine isn't about adding another thing to your schedule.
It's about becoming more intentional about something you're already using.
Turn the package over.
Read the ingredients.
Ask questions.
Learn the difference between traditional soap and other types of cleansers.
Understand what you're putting into your family's bath and shower.
Then choose according to what matters to you.
KNOW IT → USE IT → CARE FOR IT
KNOW IT
Understand what's in your bar and how it was made.
USE IT
Enjoy the simple everyday ritual of a beautifully made bar of soap.
CARE FOR IT
Let your handmade soap dry thoroughly between uses so you can enjoy it longer.
Wellness doesn't always require adding more.
Sometimes it simply means becoming more thoughtful about the things you're already doing.
Frequently Asked Questions
Is cold-process soap made with lye?
Yes. Traditional hard soap requires an alkali, and cold-process bar soap is commonly made using sodium hydroxide. During proper soapmaking, sodium hydroxide reacts with fats and oils through saponification to form soap. The FDA notes that when traditional soap is properly made, no lye remains in the finished product.
What is saponification?
Saponification is the chemical reaction that occurs when fats or oils react with an alkali. The reaction produces soap—the salts of fatty acids—and glycerin.
Is handmade soap just oil mixed with lye?
No. That's the beauty of chemistry. The starting ingredients undergo a chemical reaction and are transformed into new substances.
Is every bar cleanser technically soap?
No. Under the FDA's regulatory definition, true soap consists principally of alkali salts of fatty acids and receives its cleansing action from those compounds. Many solid body cleansers use synthetic detergents and therefore do not meet that particular regulatory definition of soap.
Is Dove soap? What about Dial or Irish Spring?
Those brands sell multiple products and formulations, and formulations can change. Rather than categorizing every product from an entire brand, look at the specific product and its ingredient list. Some mass-market cleansing bars contain synthetic detergents or combinations of cleansing ingredients.
Is essential oil always better than fragrance oil?
No. They are different fragrance materials. Both require appropriate selection and usage. Mammy's Soap Co. uses quality essential oils as well as carefully selected fragrance oils that are phthalate- and paraben-free.
Is mica bad?
Not inherently. Mica-based colorants vary in composition and source. We believe the better question is whether a particular colorant is appropriate for its intended use and meets our ingredient standards.
Why does Mammy's Soap Co. cure its soap for at least four weeks?
Curing allows water to evaporate from cold-process soap, producing a harder bar and helping improve longevity in use. Every Mammy's Soap Co. bar receives a minimum four-week cure before it is ready for sale.
How can I make my handmade soap last longer?
Keep it dry between uses. Use a draining soap dish, allow air to circulate around the bar, and don't leave it sitting in water.
This Week's Wellness Challenge
This week, we want you to do something incredibly simple:
GO READ YOUR SOAP LABEL.
Pick up the bar in your shower.
Turn it over.
Read the ingredients.
Do you know what they are?
Do you know what is providing the cleansing action?
Is it traditional soap or another type of cleansing bar?
And if there's something you don't understand...
Ask.
We believe you deserve to know what's in the products you use every day.
Know What's in Your Bar
A bar of soap may be one of the simplest products in your home.
But behind a true cold-process bar is chemistry, formulation, craftsmanship and time.
At Mammy's Soap Co., ours also carries a little family history.
Our original family recipe since 2015.
Quality oils and butters.
No added synthetic detergents. Ever.
Essential oils and carefully selected phthalate- and paraben-free fragrance oils.
Small-batch cold process.
Twenty bars per loaf.
A minimum four-week cure.
Made by a Certified Advanced Soapmaker.
Because we don't think you should have to wonder what's in your bar.
KNOW WHAT'S IN YOUR BAR.
AND KNOW WHO'S MAKING IT.
— The Mammy's Soap Co. Family
This Wellness Journal article is intended for general educational purposes. Ingredient profiles and individual skin needs vary. Always review product ingredient information and discontinue use if irritation occurs.