Herbs for Soap Making

Why add herbs to handmade soap

Herbs and dried botanicals are mostly used in soap for three reasons: appearance, texture, and the idea of a gentle, plant-based bar. Some herbs add a little color or flecks of speckle, some add very light scrubbing, and some are simply attractive on top of a loaf.

It helps to keep expectations realistic. Soap is rinsed off quickly, so the skin-care effects of an herb are likely to be modest. Many makers value herbal soap for how it looks, smells and feels to make, rather than for any strong effect on the skin.

Three ways to use herbs in soap

Most herbal soap falls into one of three approaches.

1. Herbal infused oil. Dried herbs steep in a carrier oil for a few weeks, or are warmed gently in it, and the strained oil replaces part of the oils in your recipe. This is the most reliable way to carry an herb’s character into the bar without leaving bits in it. See our step-by-step guide to infusing oil with herbs for soap.
2. Herbal tea or water infusion. A strong, cooled herbal tea can replace some of the water used to dissolve lye. Be aware that plant material in lye water can darken or change color, and the lye solution is hot and caustic, so this is a step for people already comfortable with lye handling.
3. Dried herbs in the batter or on top. Finely ground or very small dried herbs can be stirred in at trace for speckles and a bit of texture. Whole buds and petals are often used as a topping instead, pressed lightly onto the surface of the soap.

Always use dried herbs. Fresh plant material contains water, which can lead to mold, spoilage or unexpected results in a finished bar.

Herbs that work well in soap

These are among the botanicals most commonly used. Results vary by supplier, grind and recipe, so test small batches.

• Calendula. Popular because the petals tend to hold their golden color better than most flowers, and they are often used both in the batter and as a topper. Calendula is also a favorite for infused oil; see our infused calendula oil recipe.
• Lavender. Loved for its association with relaxation. The buds often darken in the bar, and some makers use lavender essential oil for scent (see soap scent recipes and combinations) and a few buds for decoration.
• Chamomile. Often chosen for sensitive-skin style bars. It can be used as an oil infusion or tea, and tends to give a soft, pale yellow to beige tint at most.
• Peppermint and spearmint. Ground leaves add a light green-brown fleck and a fresh feel. Use sparingly, as larger amounts of leaf can look rough.
• Nettle leaf. Sometimes used to give a green-brown, earthy tone, usually as an infusion.
• Rose petals and buds. Mostly decorative on top. The pink usually fades or browns with time.
• Rosemary. Often seen in infused oils and in savory, herbal-scented bars.

If you have a skin allergy, a known plant sensitivity, or are making soap for someone who does, check each botanical first and patch test finished bars.

Will herbs keep their color?

Usually not. Soaping makers commonly report that most herbs turn brown or even black in cold process soap, with calendula often cited as the main exception. Some people have had better luck with green powders such as ground parsley or wheat grass powder, which tend to give speckled results rather than a solid color.

Practical ways to manage this:

• Accept that natural, rustic browns can look attractive when the herb is evenly spread through the batter.
• Use herbs sparingly, since a lot of brown matter can look uneven.
• Keep delicate flowers for the top of the bar, and expect some fading.
• Make small test batches before committing to a big loaf.

Which herbal soap is best for skin?

There is no single best herbal soap, because skin differs from person to person. Many people with dry or sensitive skin like simple bars made with gentle oils and a mild herb such as calendula or chamomile, and with little or no fragrance. Bars with a lot of scrubby herb pieces, or strong essential oils, can feel harsh on delicate skin.

A few practical guidelines:

• Choose a well-formulated, properly cured base recipe first; the herb matters less than the soap itself.
• Keep scrubby additions fine and modest.
• Consider leaving out essential oils if your skin reacts easily.
• If you have a skin condition, talk to a clinician before relying on any soap for it.

Basic process for handmade herbal soap

Soap making with lye (sodium hydroxide) is a chemical process that requires care. Cold process soap is made by mixing oils with a lye solution until the mixture thickens (trace), pouring it into a mold, and letting it cure for several weeks. Before you try it, learn the safety basics from a reliable soap making source, and use protective gear such as gloves and eye protection.

A simple herbal approach looks like this:

1. Infuse a portion of your soaping oil with a dried herb, then strain it well.
2. Use a lye calculator with your exact oils, including the infused oil, to get the right lye amount.
3. Mix the lye solution, combine with the oils, and bring the mixture to trace.
4. Stir in any fine dried herb or fragrance, pour into the mold, and add toppers if wanted.
5. Let the soap set, cut it, and cure it for the time your recipe recommends.

If you prefer to avoid handling lye, melt and pour soap base (see melt and pour soap recipes with essential oils) lets you add dried herbs, oils and scent to a premade base. The base has already been through saponification, so you are mainly adding color, texture and fragrance rather than changing the soap chemistry.

Which plant is used to make soap?

Real bar soap is made by reacting fats or oils with an alkali such as lye, so the “plant” part is usually the oils: olive, coconut, palm-free blends, shea and others. Herbs are then added for character.

There are also plants that contain natural cleansing compounds called saponins, such as soapwort. These can produce a mild lather when steeped in water, but this is a plant wash rather than a bar of lye-based soap.

What did the Amish use to make soap?

Traditional home soap making in many farming communities, including Amish households, historically used rendered animal fat (tallow or lard) and lye made from wood ashes and water. This is the same basic chemistry as modern cold process soap, though today’s makers measure lye with calculators and use commercial lye. Exact recipes vary by family and region, so treat this as a general description.

Safety and troubleshooting

• Lye is caustic. Wear gloves, eye protection and long sleeves, and keep children and pets away.
• Use dried herbs only, and keep infused oils and herb additions clean and dry.
• Scrubby herbs can irritate. Grind them fine and use small amounts.
• Essential oils are not always skin-safe at higher levels. Follow supplier usage guidance.
• Brown spots or odd smells can indicate that the herb was not fully dry or the oil was not stored well. Discard questionable batches.

Where to go next

Once you are comfortable with the idea, try an infused oil first. Our guide to infusing oil with herbs for soap walks through the methods and safety points, and the infused calendula oil recipe is a good beginner project because calendula is forgiving and widely available.