If you’ve ever read soapmaking instructions that say, “disperse your colorant before adding it to your soap,” you may have been left with one fairly important question:
Disperse it in what?
Oil? Water? Alcohol? Glycerin? A little bit of your soap batter?
The answer is one of those wonderfully frustrating soapmaking answers: it depends.
Different colorants behave differently. Some botanical colorants release their color into oil, while others are water-soluble. Some commercial colorants have specific preparation instructions from their manufacturers. And a dispersing method that works beautifully in cold process soap may not be the method recommended for that same colorant in melt-and-pour soap.
So rather than memorizing one rule for dispersing soap colorants, it helps to understand what you’re using, what you’re making, and what you’re trying to accomplish.
What Does It Mean to Disperse a Soap Colorant?
Dispersing means distributing your colorant in an appropriate liquid before adding it to your soap.
If you’ve ever dumped a dry powder directly into soap batter and discovered tiny speckles or stubborn little clumps in the finished bar, you’ve already encountered one reason we disperse colorants first. But dispersion isn’t always just about preventing clumps.
With botanical colorants, the liquid you choose may determine which compounds you’re actually extracting from the plant material. A botanical that readily releases its useful color compounds into oil may behave very differently from one whose color is water-soluble.
And there’s an important distinction here: dispersing a powder and extracting its color aren’t necessarily the same thing.
You can suspend tiny particles throughout a liquid without actually extracting the compounds responsible for the color. If you’re primarily trying to incorporate a powdered natural colorant evenly into your soap, I have a separate guide to using powdered colorants in soap with slurries and dispersions.
For this article, we’re looking at the bigger question: How do you decide which liquid or method makes sense for the colorant you’re using?
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How Do I Know What to Mix My Soap Colorant With?
Start by identifying exactly what you have.
If you’re using a commercially manufactured colorant, such as a mica, oxide, ultramarine, or another cosmetic colorant, check the manufacturer’s instructions for that specific product.
- Not another soapmaker’s mica.
- Not a Pinterest graphic.
- Not instructions for something that looks approximately the same.
- The actual product you’re holding.
Another soapmaker may be able to tell you exactly what works with the product they use, but that doesn’t necessarily mean their solution is appropriate for yours. Manufacturers formulate and test products differently, and their recommendations may even vary depending on whether you’re making cold process, hot process, or melt-and-pour soap.
If the manufacturer says to disperse that particular colorant in oil for cold process, that’s where I’d start. If they recommend alcohol for that product in melt-and-pour, follow those directions instead.
And if you’re unsure, ask the manufacturer. They’re in a much better position to tell you how their product was designed to be used than a soapmaker who may never have worked with that particular product.
Make Sure Your Colorant Is Intended for the Job
Before worrying about whether your colorant should be dispersed in oil, water, alcohol, or anything else, make sure it’s actually appropriate for what you’re making.
This applies to both manufactured and natural colorants.
Mica powders, for example, are sold for all sorts of crafts. My sister uses beautiful pigments in her resin art. That does not mean I should wander into her art studio, grab a gorgeous sparkly powder, and put it in soap.
If you’re purchasing mica or another manufactured colorant for soap, buy from a reputable supplier and make sure the specific colorant is appropriate for the cosmetic application you’re planning. Don’t assume that because something is called “mica,” or because it’s safe for one kind of craft, it’s automatically something you should put into a product you’re going to rub all over your skin.
The same rule applies to botanicals. Natural does not automatically mean safe for your skin.
Poison ivy is perfectly natural. I don’t recommend coloring your soap with it. And while hot peppers can produce some gorgeous colors in the kitchen, those compounds responsible for all that heat aren’t something I’d casually introduce into a bar of soap you’re planning to rub over your body.
Before experimenting with any botanical, research the plant itself and make sure it’s appropriate for topical use. Also remember that the part of the plant can matter. A flower, root, leaf, seed, or essential oil from the same plant isn’t necessarily interchangeable when we’re talking about safety.
Whether your colorant came from a laboratory, a soap supplier, your garden, or Mother Nature herself, “Can I use this safely?” comes before “What color will it make?”
Manufactured Colorants Come With Instructions. Plants Don’t.
Once we’ve established that our colorant is appropriate for soap, botanicals present us with a different challenge. There isn’t a manufacturer’s technical sheet for alkanet root. Mother Nature made it, and unfortunately, she does not have a technical-support department. 😂
- With a manufactured colorant, we can usually turn to the supplier for information about usage rates, appropriate applications, stability, and recommended dispersion methods.
- With botanicals, we have to do more of that homework ourselves.
Botanical colorants vary naturally, and the compounds responsible for their colors don’t all behave the same way. Some are better suited to oil infusions. Some readily release color into water. Some can be added directly to soap. Some can be used in more than one way, and changing the method can change the result.
If you’re trying to figure out which method to use, start with my Botanical Soap Color Index. It lets you explore the natural colorants I’ve tested and the colors they can produce.
Want something you can keep beside your soap pot? The free Botanical Soap Color Chart includes helpful information about preparing and using these colorants, including whether they’re oil- or water-soluble. You can get the chart inside the free Soapy Friends Starter Kit, along with other free soapmaking classes, guides, labels, and tools.
But even knowing whether a botanical is oil- or water-soluble doesn’t tell us everything. Because then we put it into soap…
And soap has chemistry of its own.
Botanical Colorants and pH
One of the things that makes natural soap colorants so fascinating, and occasionally maddening, is that many plant pigments are sensitive to pH. The color you see when you mix a botanical with water or infuse it into oil isn’t necessarily the color you’re going to see in your finished soap.
Cold process soap begins in an extremely alkaline environment. As saponification progresses, the chemistry changes, and botanical compounds can react right along with it. A gorgeous plant infusion can become an entirely different color once it encounters lye.
Sometimes that’s exactly how we get the color we wanted.
Sometimes it’s how we get a color we absolutely did not expect.
Welcome to natural soap coloring. 😆
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Can You Use Botanical Colorants in Melt-and-Pour Soap?
Yes, botanical colorants can also be experimented with in melt-and-pour soap, but there’s an important distinction: Don’t assume a botanical will produce the same color in melt-and-pour that you’ve seen it produce in cold process soap.
With cold process, the botanical experiences the highly alkaline environment and changing chemistry of saponification.
With a finished melt-and-pour base, the manufacturer has already made the soap. You’re melting a finished product and adding your colorant rather than exposing that botanical to the same saponification process. For pH-sensitive plant pigments in particular, that can make a very noticeable difference.
If you’re curious about that distinction—or wondering whether melt-and-pour “counts” as soapmaking—I wrote more about melt-and-pour, making soap from scratch, and why I think you should make soap your way.
Years ago, one of my Soapy Friends, Minal Doshi, experimented with a wonderful collection of botanical colorants in melt-and-pour soap and shared her results with our Facebook group. She carefully documented how she prepared each botanical, so I’ve included some of her experiments below along with her original preparation notes. Hover over, or tap, on each photo for the notes.
These examples aren’t recipes or promises that you’ll get exactly the same results. They’re experiments showing what’s possible. Botanicals vary. Melt-and-pour bases vary. Growing conditions, storage, extraction methods, usage rates, and plenty of other variables can influence natural color.
That’s precisely why I find experiments like these so useful.
Should I Disperse My Soap Colorant in Oil or Water?
If I’m working with a botanical colorant, one of the first questions I ask is: Where are the color compounds I’m trying to capture soluble?
If they’re oil-soluble, an oil infusion may make sense.
If they’re water-soluble, using the botanical in the water portion of the recipe or creating an appropriate water-based extraction may give you a completely different result.
And sometimes the interesting answer is to test more than one method.
You don’t necessarily have to make an entire batch of soap every time you want to learn something, either. My How to Test Natural Colors Before Making Soap video demonstrates a quick lye-test method I use to get an early look at how a botanical may react before committing it to a full batch.
That’s especially useful when the gorgeous red, purple, or green sitting in your little cup is about to meet a very alkaline soapmaking environment.
Can You Use Alcohol to Extract Botanical Soap Color?
Alcohol adds another interesting possibility. Botanicals can be macerated in alcohol to create a tincture, allowing alcohol-soluble plant compounds to be extracted before they’re introduced into a formulation.
We touch on alcohol extraction in my Extracting Color from Nature material, although the bulk of that series focuses on the oil- and water-soluble methods I use most often. The Extracting Color from Nature series includes dedicated masterclasses on oil infusions and water-soluble botanicals.
But there’s something especially important to remember if you’re considering alcohol in soapmaking:
Alcohol is flammable. Soapmaking can involve significant heat.
Saponification itself is an exothermic reaction, meaning it generates heat, and hot process soap introduces an additional external heat source. So alcohol isn’t an ingredient I’d casually experiment with around a hot soap pot. If you’re working with an alcohol tincture or another alcohol-containing preparation, understand the alcohol concentration you’re using, pay attention to your temperatures, and keep it away from flames, heating elements, and other ignition sources.
What About Alcohol With Mica or Melt-and-Pour Soap?
Alcohol also comes up frequently in discussions about melt-and-pour soap and commercial colorants such as mica.
This is where we come right back to the advice from the beginning of this article:
Follow the directions for your particular products.
I don’t personally make commercial melt-and-pour soap or use mica, so I’m not going to pretend that my soapmaking experience makes me an expert on every melt-and-pour base or every mica on the market.
For some products and applications, alcohol may be exactly what the manufacturer recommends. For another, the instructions may be different. While a well-meaning soapmaker may give you completely accurate instructions for their base and their colorant.
You need instructions for yours.
What About Glycerin?
You’ll also see glycerin recommended as a dispersing medium for some colorants and applications.
Again, whether it’s appropriate depends on the colorant and what you’re making. Glycerin can be useful for wetting and dispersing certain powders, but I wouldn’t automatically reach for it simply because you’ve seen another soapmaker use it successfully.
For manufactured colorants, follow the supplier’s recommendations.
For botanicals, think first about what you’re actually trying to accomplish:
Are you simply trying to distribute the material evenly, or are you trying to extract its color?
Those are not necessarily the same job.
And glycerin has plenty of other interesting uses in soapmaking too. I actually add it to my floating soap formulation in the Salting Out Soap Tutorial. That tutorial starts with salted-out soap and shows how I turn it into several useful products, including a fresh bar of soap that floats.
There Isn’t One Correct Way to Disperse Every Soap Colorant
If there’s one thing I want you to take away from this article, it’s this: Don’t memorize “mica goes in this” or “botanicals go in that.” Learn to ask why.
Ask yourself:
- What colorant am I actually using?
- Is it a manufactured cosmetic colorant or a botanical?
- If it’s manufactured, what does its manufacturer recommend?
- Am I making cold process, hot process, or melt-and-pour soap?
- If it’s botanical, are the color compounds I’m interested in oil-soluble, water-soluble, or something else?
- Am I trying to extract color or simply disperse particles?
- Could the pH and chemistry of my soap change the color I’m expecting?
Those questions will get you much farther than one universal dispersing rule ever could.
The Best Way to Learn? Experiment.
We don’t have a manufacturer who can tell us exactly how this year’s crop of alkanet is going to behave in our particular recipe. So we experiment. We make small batches. We take notes. We compare results.
And sometimes the weird batch teaches us more than the perfect one.
If you’re using a commercial product and can’t find the answer, there’s no shame whatsoever in saying, “I don’t know.” Check with the people who made it. Find the right information for the actual product you’re using.
And if you’re experimenting with botanicals, come back and tell your Soapy Friends what happened! That’s how this whole wonderful library of shared soapmaking knowledge keeps growing.
Continue Learning with Soapy Friends
Once you start asking why a colorant behaves the way it does, soapmaking gets a whole lot more interesting. Natural color especially gives us endless opportunities to experiment, compare results, and learn from one another.
If you’d like to continue learning and soaping along with me, here are a few great next steps:
Explore the Botanical Soap Color Index to see natural plant-based colorants and the colors they can produce in soap.
Get the free Soapy Friends Starter Kit for the printable Botanical Soap Color Chart, plus free classes, guides, labels, and other soapmaking tools.
Learn more with the Extracting Color from Nature Master Class Bundle if you want to spend some serious time experimenting with oil infusions and water-soluble botanical colorants.
Or, if what you really want is an ongoing place to experiment, troubleshoot, and learn the chemistry behind what happens in your soap, join me inside the Soapy Friends membership. That’s exactly the kind of thing we get nerdy about together.
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