The use of natural ingredients in body care products, long a popular commercial trend, continues to increase. Adding herbs and other natural additives can increase customer demand, label appeal, and overall aesthetics. Additives such as herbs and flowers, coffee and tea, nuts, chocolate, oatmeal, silk fibers, and even tobacco can be added for many different reasons. For starters, many of them have excellent antioxidant properties, which can help to increase the skin-loving traits of your bar. Others make for great use as exfoliants. They can also help to color your soap or add texture.
When adding natural products to soap, there are a few things to take into consideration:
Will it discolor?
While some herbal additives produce beautifully colored soap, most others will eventually turn brown and discolor the final product. Some cause a “halo” effect where the color spreads out from the herb particles in the soap, eventually taking over most of the bar. You’ll want to plan for this when creating your soap design. Or just use those soaps up more quickly!
How scratchy will it be?
If you’re using additives as an exfoliant, you’ll want to do some testing to find the correct “scratch factor.” A product that is ground too finely or used in very small amounts will be unnoticeable; using larger chunks or adding too much of it could potentially cause harm. (Nobody wants to lose a layer of skin!)
Is this additive a possible allergen?
Additives like nutshells could cause an allergic reaction in some sensitive people. You’ll want to make sure you add a warning to your label if using any of these. (See Considering Nut Allergies.)
Should I use the herb itself or make an infusion?
When using herbs to color your soap, you’ll need to make an oil infusion to extract as much colorant as possible. To use them as an exfoliant, to add texture, or for aesthetic purposes, adding the actual herb directly at thin trace is fine. (See directions on making herbal infusions.)
How long will natural colors last in soap?
How long color lasts depends on the ingredient. Natural green colors tend to fade fairly quickly (within a couple of weeks) to brown or gray or even become almost non-existent. Shades of orange and red, such as the tomato color in Layered Tomato Swirl Bars will fade, but not as drastically or as quickly as the greens.
Keeping your soap out of direct sunlight can help extend the life of the color. A good alternative to natural colorants is to use nature-identical oxides, which are often called for in this book. They hold their color much better.
Depending on its labeling and intended use, a botanical product can be considered a food, a dietary supplement, a drug, and/or a cosmetic. While it is possible to incorporate nearly any botanical item into your product, the FDA has differing rules for how they can be used. Specifically, many herbs and additives can be used for their healing or supportive properties but are not approved for use as colorants, even though many herbs (and other additives, such as clay) impart lovely colors to soap.
For example, spirulina makes your soap turn green. However, the FDA has only approved spirulina as a colorant in the narrow category of candy, gum, and confection. If you just want green soap for personal use, you don’t have to worry about this. But if you use spirulina in soap that you plan to sell, you must add it for the herbal properties and not its natural green color.
Do your research on the therapeutic properties and approved FDA uses of your chosen ingredients, so that you don’t run up against labeling laws. Labeling your product with any claims such as “warming” or “healing” or “anti-aging” requires following the requirements of the FDA for production of a drug rather than a cosmetic.
There are dozens, if not hundreds, of herbal, mineral, botanical, and other materials that can be added to soap to create colors, impart specific characteristics, and increase the appeal of the final product. Here are just a few that are used in recipes in this book.
Clays are used to impart color to soap (see All about Color and Using Clay to Color Soap) and can also add “drag” (mild exfoliating property) or “slip” (a slick feeling), depending on the type of clay used. This makes clay soap an excellent shaving bar but may surprise people who are using clay bars for the first time. Additionally, clay is a strong odor-masking agent. This makes it ideal for deodorizing soap but less ideal if you prefer to smell the essential oil in your soap.
Coffee grounds are a great additive for a super exfoliating bar. They can be ground to whatever texture you desire. For extra scrubbing power, use a coarse grind, while for gentle exfoliation, a super-fine espresso grind is best. Use the grounds to make coffee before adding them, or they might bleed brown halos into the final soap.
Colloidal oatmeal has long been used as a soothing bath additive. It is ground micro-fine, and is extremely gentle, giving just a hint of texture in the final bar without being scratchy. It usually appears slightly gray in the final soap. Adding colloidal oatmeal can accelerate trace in your soap recipe; premixing with water can help avoid this.
Honey can be tricky as a soap additive, but it can create some wonderful results. Honey is known for its antimicrobial properties as well as its humectant abilities, and sugar in general enhances lather. While sugar can impart some fantastic properties to your soap, it also introduces factors to work around. Sugar and lye react to create excess heat, which can cause extreme gel phase, sweating, cracking, heat tunneling (large holes in the center of the soap), or even make the soap erupt from the mold. To work with honey, start soaping with lye-water and oils both under 100°F (38°C). Add the honey at trace, and stick-blend in short bursts to disperse it into the batter. Once the soap is finished, place it in the refrigerator or freezer immediately to prevent overheating.
Oxides and pigments are called for throughout this book to add color in recipes. These dry powders are much more easily incorporated into soap batter when mixed into a light oil such as sweet almond or rice bran oil. The standard ratio is 1 part oxide to 3 parts oil. You can mix the color and oil together with a spoon, but an electric mini mixer such as a latte frother is wonderful to ensure there are no chunks of color in the mixture. Store extra colorant in the refrigerator and discard after one month. (Read more about oxides and pigments on the next page.)
Salt is a versatile additive that creates an extremely hard and white bar. Sea salt is commonly used for soap as it contains many minerals and creates label interest. Salt decreases lather significantly, so a very cleansing, high-lathering oil such as coconut oil may be needed for balance. Salt can be added at trace to create an exfoliating textured bar, or to the lye-water (see 100% Castile-Brine Stamped Cube). Salt-added soap is best made in an individual cavity mold, as a loaf becomes too hard and brittle to cut without damaging the bars.
Tussah silk is made of very fine, soft fibers harvested from wild silkworms. Adding silk to your soap creates a slick, soft feel to the lather, and many soapers will not soap without it. To use it, add a very small pinch of the fibers to the water before the lye is added. Pour the lye directly over the silk and stir continuously. The fibers will begin to dissolve as you stir. Once the silk is dissolved, continue with the recipe as usual. The fibers can be added to any recipe and will not affect the final appearance of the bar.
Walnut shells can be found pre-ground at many soap suppliers. They are typically finely ground for skin care, and make an excellent facial soap. They do not bleed color, but will appear as brown flecks in the final bar.
Using a mini mixer ensures that clay and other additives are evenly mixed before being added to soap batter.
Herbal extracts are a great way to add antioxidants and vitamins from plants into your soaps. Extracts for soaping are oil- or water-based liquids that contain the active ingredients of an herb in a concentrated form. Alcohol-based extracts, such as tinctures or baking extracts, can have adverse, possibly dangerous, reactions in the soaping process, so they should not be used. Some oil-based extracts are also effective colorants that give your soaps some pop without using synthetic alternatives.
Extracts are made by infusion or decoction. Making infusions and decoctions is easy; the methods differ only slightly. To make an infusion, submerge the herb, typically leaves and other soft plant matter, in very hot liquid and let it steep for a while (see Making Herbal Oil Infusions to Color Soap). Bark, seeds, and other dense, hard material must simmer for an extended period of time to extract their active ingredients; after straining out the material, the resulting liquid is a decoction.
Please note that these are not baking extracts, but botanical extracts specifically prepared for their herbal properties. Baking extracts are often alcohol-based and should never be used in soapmaking. Botanical extracts may be added to cold-process soap to enhance or increase the therapeutic properties, for antioxidant properties, or to add label value.
Add the extract at thin trace for the best chance of the extract making it through the saponification process. There is some debate in the soapmaking community as to whether the constituents in extracts survive. Because of this, many soapers prefer to use extracts in hot-process or rebatch soap where the delicate extract is not exposed to active lye. When the main purpose of using an extract is to add color (see Herbal and Other Additives for Soap), preserving the herbal benefits is less of a concern.
Since extracts are a more potent version of active ingredients, less is generally needed to gain the benefits and they are often added at trace in the soapmaking process. Some recipes in this book use tea to make the lye-water for an interesting twist; this is a different method than using extracts. (See Using Tea to Color Soap.)
You can use many things to color your soap. The most common are food coloring (FD&C colorants), pigments and oxides, clays, and natural herbal infusions.
FD&C (Food, Drugs, and Cosmetics) are man-made colorants that are approved by the FDA for use in those three products. FD&C colorants can be found in ordinary foods (for example, farmed salmon and brightly colored candies), many brands of vitamins, and of course, cosmetics such as lipstick and eye shadow. Sold as LabColors, among other trade names, they produce vibrant colors that are fun, interesting, and varied. FD&C colorants are not considered natural, however. They are not used in any of the recipes in this book.
Pigments and oxides are a class of colorant that are either mined from the earth or manufactured in a lab. Because of impurities naturally found in products coming from the earth, pigments and oxides must be stringently purified to meet safety requirements regarding lead and other heavy metals. Many labs choose to bypass this process and instead manufacture pure colorants. Technically man-made, these colorants have the same chemical composition as mined ones, minus the heavy metals. Because of this, many people consider pigments and oxides as “natural” or “nature-identical.” Pigments and oxides are light-fast and color-stable, meaning they do not fade and do not bleed in soap.
Clays are technically purified dirt. They are a natural raw material of mineral origin, composed of fine particles of silicates and many micro-minerals such as titanium, magnesium, copper, zinc, aluminum, calcium, potassium, nickel, manganese, lithium, sodium, and iron. Clays vary greatly based on where they come from, with the composition of the earth, the water, and the climate of a region changing properties such as color.
Clays in the United States are extracted from sites that are approved and controlled by the Bureau of Land Management and the United States Geological Survey. They are dried in the sun, ground to a fine consistency, and subjected to a heat and ozone gas process to kill microbial growth. Some clays are also sterilized using gamma irradiation. This is why utilizing actual dirt from your back yard is not a good idea; it will not have been purified to appropriate standards. Do not use craft clay, molding clay, or any other type that is not specifically designed for cosmetic use.
Herbal oil infusions are a common way of adding color to soap, even though they are technically not approved by the FDA for that purpose (see A Word from the FDA). The color imparted by some herbs does fade over time, so not all herbs can be considered colorfast. The result varies based on the herb used. See Herbal and Other Additives for Soap for more information.
Using natural herbs or colorants in your soap requires that you plan ahead, sometimes weeks in advance. Keep in mind that the natural color of the soapmaking oils and the color of your essential oil (used for scent) both color your soap; this is the color that provides the canvas from which you are starting. For example, an alkanet root infusion in cold-process soap normally creates a beautiful gray-purple-blue color. However, if you use orange 10x (very concentrated orange essential oil) with it, the color goes to an unattractive green.
Infusing herbs in oil is simple. It is best to use fully dried herbs to reduce the potential for contamination by yeast, mold, or bacteria in the final product. To achieve a strong color, most soapers use at least 2 tablespoons of herb for every 4 ounces of oil. I prefer to use a tablespoon of herb for every ounce. Use an oil with a long shelf life, such as jojoba oil or olive oil.
There are several methods for making herbal oil infusions. Infusions will keep in the refrigerator, so if you find that you like a particular one, make a larger batch so you’ll have it on hand whenever you want to make soap. A reasonable amount might be a quarter to a half cup at a time.
Keeping good notes is key to reproducing great results, especially when working with something as crop-dependent as natural colorants. Here is some useful information to have:
This method is significantly faster than doing a cold infusion and is the method suggested for the recipes in this book. Add the herbs and oil to the top pot of a double boiler and stir to cover the herbs. Bring the oil to medium heat (approximately 120°F [49°C]) then let the water in the bottom pot simmer for 4 hours, stirring the herbs every 20 minutes.
Do not leave the stove unattended. If the oils get too hot (above 130–140°F [54–60°C]) the herbs will burn. This smells bad and turns your infusion brown.
Pour the infused oil through a fine-mesh strainer to remove most of the herbal matter, then filter it through a layer of cheesecloth to remove remaining larger particles or a coffee filter for fine particles. Funnel the colored oil into clean bottles and store in the refrigerator.
Alternate method: Add dried herbs to a heat-sealable teabag, filling the bag just halfway full. (You want them to have room for the oil to mix in.) Put the bag into the oil in a double boiler or, if doing several infusions at once, put each bag in a separate canning jar with oil. Make sure the oil comes close to reaching the lid. Screw the lid on tight. Place the jars in a hot-water bath on medium heat for 4 hours, never leaving the setup unattended.
A heat-sealable teabag is a convenient way to infuse herbs into oil.
Add the herbs to a small glass jar and cover them with oil. Seal the jar and set it aside for 4 to 6 weeks, checking weekly to ensure there is no mold on the herbs or condensation forming on the underside of the lid. If you do find any moisture, wipe the lid with rubbing alcohol and a clean paper towel. When the steeping period is over, filter the oil through a fine-mesh strainer and then through a layer of cheesecloth or a coffee filter to remove any last remnants.
Most of the recipes in this book call for just a few teaspoons of infused oil, but it makes sense to make at least a tablespoon or two for any given recipe, as it’s hard to work with smaller amounts. You can keep the leftover oil for use in other batches, so if you soap a lot, it might make sense to scale up the amounts to a quarter cup or more so that you have some on hand when you need it.
No matter what your infusion method, store infused oils in the refrigerator to help prevent mold and bacterial growth caused by any bits of herb left after straining. You might be tempted to add vitamin E oil, rosemary oil extract, or grapefruit seed extract as a preservative, but while these are effective antioxidants, they are not preservatives. Using them will protect against rancidity but will not prevent mold or bacteria from forming. Use all infused oils within 6 months.
Synthetic preservatives for oil-based formulas — for example, LiquaPar oil, LiquaPar Optima, LiquaPar PE, and Phenonip — are available, but I have never found it necessary to use them. The risk of mold is slight to begin with and refrigeration is effective.
When working with clays in cold-process soap, it is important to take into account their effect on the soaping process. Clays are added as powders, so they will absorb moisture, either while you are mixing them or during the curing period. The addition of clay can accelerate trace, meaning you have to be ready to pour it in the molds immediately. It also limits your ability to work with patterns and designs.
Different clays have varying levels of absorption, so always try a small test batch prior to making a big batch of a clay soap.
There are two ways to incorporate clay easily and (mostly) effortlessly into your cold-process soap. For this book, all of the clays are used with the following method.
Using a mini mixer, combine the required amounts of clay and water 4 hours in advance of starting your recipe. Generally, a ratio of 3 parts of water to 1 part of clay works well. If the clay absorbs too much water, add more water until the mixture remains liquid (strive for a consistency somewhere between cake batter and fudge). Add this slurry to your soap before you add your essential oil, and mix it in well.
You can also add the clay directly to the water before mixing in the lye. The heat reaction from the lye-water will produce a deeper color than will adding the clay at thin trace, so if utilizing this method, start with half the clay you were planning to use.
With this method, any small amount of grit or sand in the clay will fall to the bottom of your mixture, so prior to adding the lye-water and clay solution to your soap, strain it through a stainless steel strainer lined with a coffee filter to remove the undissolved grit. Be prepared, though; your batch may still accelerate.
2 tsp powder per pound of soap. Will fade with exposure to light.
2 tsp powder per pound of soap. Gel phase enhances the color. Will fade substantially with exposure to light.
2 tsp powder per pound of soap. Beautiful green color will fade with exposure to light, but is more stable than some other natural greens.
2 tsp powder per pound of soap. Color is enhanced by a hot gel phase, but will fade substantially with exposure to light.
2 tsp powder per pound of soap. Can be added as a dispersed powder (shown in photo below) or added directly to hot lye-water before combining oils.
2 tsp powder per pound of soap. Can be used as an infusion or dispersed powder. Infusion will fade over time; dispersed powder is more color stable.
0.8 oz essential oil per pound of soap. Will fade with exposure to light.
2 tsp infusion per pound of soap. Will fade somewhat with exposure to light, but a stronger infusion will help it hold its color.
2 tsp powder per pound of soap. Can also be infused and added at 4 tsp infusion per pound of soap. Gives a speckled appearance; color will leach out from spots over time.
2 tsp powder per pound of soap. Disperse in distilled water instead of oil. Holds color nicely and will not fade.
2 tsp powder per pound of soap. Can be added as a dispersed powder or infused.
2 tsp powder per pound of soap. Dispersed powder can be added at trace, or the dry powder can be infused into lye-water to create a more yellow hue.
2 tsp powder per pound of soap. Gel phase enhances the color, as does exposure to air.
For the soaps featured below, all powdered additives were dispersed at a ratio of 1 part powder: 3 parts oil. (For infusion directions, see here.) The colorants were added at trace and went through gel phase. The usage rates listed above represent the color shown in the photos below; increase or decrease the amount of colorant used to achieve your desired color. Note that some of the soaps look grainy initially but the color evens out over time.
Double-tap the image to open to fill the screen. Use the two-finger pinch-out method to zoom in. (These features are available on most e-readers.)