How to Make Herbal Soap with Rosemary and Peppermint
Learn to make herbal soap with essential oils, mineral color, and dried herbs and flowers. Part of the Simple Soap Recipe series.
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Herbal essential oils are varied and relatively inexpensive which makes them great for soap making. In this piece you’ll learn how to make herbal soap using rosemary and peppermint essential oils along with citrusy lemongrass. That combination of scent is visually illustrated with the scattering of calendula petals on an otherwise green soap. It’s a great combination that you’ll have fun both making and using.
Naturally scented soap is almost always made with essential oils. Concentrations of a plant’s volatile oils that are not only therapeutic but smell nice too. They’re the bottled life force of the plant and each has its own special properties. Rosemary oil is stimulating and aromatic and peppermint invigorates the mind and your skin. Lemongrass is a pleasing green yet citrus scent that gives this soap an uplifting note.
Herbal Soap Ingredients
Aside from the essential oils already mentioned, the other main ingredients are base oils, sodium hydroxide, and water. Making soap is creative but it’s also chemistry. Sodium hydroxide, called lye, breaks apart the oils used and then reforms it into a new compound that we know as soap. All soap is made this way, even melt-and-pour soap has been through this process before you begin working with it.
Each oil used will give your bars a different quality be it hardness, conditioning properties, or lather. I’ve also formulated the recipe to be palm-oil free, and to use a nature-identical mineral to tint the bars a pretty shade of green.
Make Herbal Soap with Dried Herbs
Although optional, I think that decorating soap with dried herbs and flowers makes it more attractive. It may not necessarily add therapeutic properties, at least not in the same way that essential oils, but it does add interest and sometimes exfoliation.
In this recipe I’ve added dried peppermint for visual effect and to match the essential oil used. One really fun thing about dried peppermint is that it will bleed into the soap over time. If you look around the peppermint in the image below you’ll see warm colored halos around the pieces. It’s a warm tone that matches the calendula flowers but you’ll only begin to see it during the curing process. If you wanted to, you could even add a pinch of dried peppermint to the entire soap batch. They’ll create a speckled effect similar to my peppermint soap. Learn more about using herbs, flowers, and other botanicals in soap.
How to Make Soap
Almost all of the recipes you’ll find on Lovely Greens are geared for the beginner to intermediate soap maker. That means that if you’re new to soap making you should be able to make herbal soap fairly easily. However, you’ll have a better understanding of what’s involved if you have a read through the Natural Soap Making for Beginners Series:
- Natural Soap Ingredients
- Soap Making Equipment & Safety
- Beginner Soap Recipes
- The Soap Making Process
Soap Making Equipment
Much of the soap making equipment you need could already be in your kitchen. Rubber washing-up gloves, bowls, and even silicone molds. If you don’t have everything, you can purchase it online relatively inexpensively. Also make sure to check out second-hand shops for pots and other items.
To protect yourself from the lye-solution you should always wear eye protection (goggles) and rubber gloves. Here’s more of what you’ll need:
- Digital Thermometer gun
- Digital Kitchen Scale
- Stick (Immersion) Blender
- Stainless steel pan for melting the solid oils
- Heat-proof jug for the lye-solution
- A large bowl for measuring the liquid oils into
- Rubber spatula for stirring and scraping
- A small dish for mixing the color in
- Small sieve (strainer)
- Mixing color is a whizz with a milk frother
- A standard take-out container as a soap mold. Line it in baking/grease-proof paper
Simple Soap Recipe Series
When learning to make handmade soap I’d highly recommend working with a single base recipe. That way you’ll know what to expect each time you make it, be able to spot any differences or issues quickly, and save money.
That’s why this herbal soap is part of the Simple Soap Recipe Series. Each of the recipes uses the same main base oils, water, and lye amount. They’re made unique by using different scents, color, and natural decoration. Aside from this recipe I’ve also shared a gorgeous citrus soap and two beautifully scented floral essential oil soap recipes.
- Zesty Citrus & Calendula soap recipe
- Lavender & Poppy seeds soap recipe
- Rose Geranium soap recipe
- Get the Lovely Greens Guide to Natural Soapmaking
Herbal Soap Recipe with Rosemary & Peppermint
Equipment
- Stainless steel pan for melting the solid oils
- A large bowl for measuring the liquid oils into
Ingredients
Lye water
- 64 g Sodium hydroxide (2.27 oz)
- 115 g Distilled water (4.06 oz)
Solid oils
- 146 g Coconut oil (refined) ( 5.15 oz)
- 52 g Shea butter (1.83 oz)
Liquid oils
- 123 g Olive oil (4.34 oz (light colored olive oil))
- 51 g Sunflower oil (1.8 oz)
- 45 g Sweet almond oil (1.59 oz)
- 37 g Castor oil ( 1.31 oz)
- 1/16 tsp Chromium green oxide ((optional mineral color))
Add after Trace
- 3.4 g Rosemary essential oil (3/4 tsp)
- 3.7 g Peppermint (Mentha piperita) essential oil (3/4 tsp)
- 3.4 g Lemongrass essential oil (3/4 tsp)
- 1/2 tsp Dried calendula petals ((optional))
To decorate
- Dried peppermint leaves
- Dried calendula petals
Instructions
- Pre-mix the Chromium green oxide in about a Tablespoon of the olive oil. Prepare your soap mold(s) now too. The one I'm using is a clean take-out container lined with two strips of baking paper. One laid lengthwise, and the other one across. Leaving overlapping paper will help you get the soap out when it's ready.
- Next, dissolve the lye (Sodium hydroxide) crystals in water. Gear up with eye protection, gloves, and wear a long sleeved top. In an airy place, outdoors is best, pour the lye crystals into the water and stir well. There will be a lot of heat and steam so be careful. Try not to breath it in. Leave outside in a safe place, or in a shallow basin of water to cool.
- Melt the solid oils in a stainless steel pan on very low heat. When melted, remove from the heat and set on a pot holder. Pour in the liquid oils including the colored oil.
- Measure the temperatures of the lye-water and the oils. You should aim to cool them both to be about 120°F / 49°C.
- Pour the lye-solution into the pan of oils. I tend to always pour the liquid through a sieve to catch any potential undissolved lye or bits.
- Dip your immersion blender into the pan and with it turned off, stir the mixture. Next, bring it to the center of the pan and with both your hands, hold it on the bottom of the pan and blitz it for just a couple seconds. Turn it off and stir the soap batter, using the blender as a spoon. Repeat until the mixture thickens up to ‘Trace’. This is when the batter leaves a distinguishable trail on the surface. The consistency will be like thin custard.
- With your spatula, stir in the essential oils. If you'd like a few calendula petals on the inside of the soap, stir in the optional 1/2 tsp of them now. Working quickly, pour the soap into the mold(s). Sprinkle the top with dried peppermint first then a few more calendula petals.
- Turn your oven on to very low and heat for just a minute or two until it's 100°F / 38°C. Then turn your oven off, and pop your soap mold(s) inside. Leave overnight. Oven-processing the soap like this intensifies the color.
- The next day, take the soap out of the oven and set someplace to rest for another day. Once 48 hours have passed, you can take the soap out of the mold(s). Cure it for 28 days before using. Curing means leaving the bars spaced out on a protected surface out of direct sunlight and in an airy place. This allows the extra water content to fully evaporate out.
- Once made, your soap will have a shelf-life of up to two years. Check the oil bottles that you’re using though — the closest best-by date is the best-by date of your soap.
Notes
Hi again!
I’m getting ready to make this soap, my first batch ever! So excited!
Since I’ll be using silicone molds (to make fun shapes for the soap) I won’t have access to the tops of my soap to sprinkle the peppermint leaves or the calendula petals, and I’d really like those on the tops of my soap! I was wondering, could I just add some of the peppermint and calendula to the molds before adding the soap (so that, in theory, the leaves/petals stick to the top of the soap) or would it be best to wait until cured then use the alcohol method to spray and sprinkle the leaves/petals on the soap at that time? Or is there a better way I don’t know of?
Blessings and thanks again!
Baily
Hi Baily, and yes, you could do this. I also recommend that you read this Guide to using Herbs and Flowers in Soap Recipes
Oh thank you so much! I’ll give that a read right now! Also this soap came out BEAUTIFULLY for me! I love it so much, it literally smells like the cusp of summer! I did two batches: one in silicone molds and one in a loaf pan (that I did my first double batch for) and both came out amazing! I have learned that floral decor kind of hides the shapes of my cute silicone molds, so when I do silicone I won’t be doing flowers/herbs, but the loaf pan is PERFECT for this recipe and the beautiful calendula/peppermint leaves! Thanks so much again for this recipe!!
Blessings,
Baily
Glad to hear that it turned out so well :) You’re very welcome!
Also, where did you purchase your chromium green oxide?? I’m in love with the color of this soap, and when looking at options online there are quite a few different shades of chromium green oxide out there, and I really want to pick the right one!
Blessings!
Baily
I tend to order oxides and minerals through the Soap Kitchen (UK).
Thank you so much! I’m in the United States so shipping from the UK isn’t super feasible, BUT I did find a chromium green oxide that looks just like the one Soap Kitchen (UK) carries at Bramble Berry! I also have spinach powder I’m going to test with in a separate batch to compare colors :)
Thanks again! Blessings!
Baily
Hi there!
I’m allergic to coconut and sweet almond oil. Could I substitute other oils for these or even just use more of the sunflower or castor oil?
Thank you! Blessings!
Baily
Hi Baily, if you change any of the oils in the recipe, you would need to recalculate the amount of lye needed to saponify it. Fortunately, babassu oil is an almost exact substitute for coconut oil – in properties and in the amount of lye needed. If you wanted to change the sweet almond oil to something else (more olive oil, I’d recommend), you’d need to use the soap calculator on soapcalc.net to recalculate. Here’s how to change and customize soap recipes. Also, are you allergic to these oils on your skin or to the foods if you eat them? They’re quite different, but there’s a lot of confusion around it.
Hi again thanks so much for your quick reply! :). I’ve been making organic/natural cosmetic and personal care products for a year now (do still fairly new to that!) but am brand new to soapmaking so thank you so much for your patience!
I was actually wondering if I could sub the babassu for the coconut, and yes I remembered from your article after rereading again that I’d need a different amount of lye if I did that ;). After reading your other very good and informative articles I decided to sub the sweet almond with apricot kernel oil as it appeared to be the closest to sweet almond for soap making purposes, but I read you recommended more olive oil so now I’ll do a bit more research before deciding between the olive and apricot kernel oils :) Although I’m leaning towards the olive since you’re much more experienced than I am!
I am allergic to the coconut on both my skin (I get very large and painful cystic acne) and in my food but I’m not sure about the sweet almond since I’ve been avoiding it for years after I learned I couldn’t eat almonds. Thanks for the info on that! I’ll try a patch test of the sweet almond on my skin and see as I’m very curious at this point, but since I sell or gift what I don’t use myself I think I’ll continue to avoid using the almond since one of the ladies I usually sell to cannot eat or have almond/nut containing products on her skin without having a pretty serious allergic reaction.
Thanks again so much for all of your help and for producing so many awesome articles and (beginner friendly) recipes!
Blessings!
Baily
I placed my mold with my trace soap on the oven (off) , after an hour, I checked just for fun, and it had a big crack along the middle of the soap, what did I did wrong, was the oven too hot maybe> if all is chacked can I rebatch it with hot process on crock pot,just like the parsley recipe, thank you
Hi Mariela and yes, the soap got too hot. Do you live in a warm climate? If so, then you only need to leave the soap on the countertop for it to gel. Just lightly cover it with a tea towel :)
Thank you for this fresh idea that smell like spring! I’ve got a question though. Do you think adding some hemp oil can give that nice green colour ? Or adding some green clay? I don’t have the green oxide. Have a nice day
Hi Yulia and I have another piece where you can find lots of ideas for natural soap colorants, including green :)
Hello I just tried the p&m soap it went well but I’d like to know if the liquid Castile soap could be made thicker by adding olive oil and how
Hi
I am a chemical engineering graduate from Iran.
I saw your work in the field of making herbal soaps and I became very interested in making herbal soaps due to the abundance of medicinal plants in my area, so I need your help in this field.
Please help me with this I will be much appreciated for your help.
Thank you
Thanks for sharing! What a great scent combination!
Thanks for sharing! Can I make other scent combination with this base recipe?
Of course! Here are tips on using essential oil to scent natural soap.
This looks so good! I love this scent combination!
Hey!
Thank you for such a great recipe.
I am new to soapmaking and your blog is really helpful!!
I just wanted to know if I can skip the oven part as I don’t have an oven.
Yes, that’s a purely optional step :)
Tanya
I just made this recipe….my first ever CP soap! I followed everything precisely-however. The amount only half filled my mold. My mold is 8″x3.5″ and 2.5″ deep. Is it too big? How do I find the correct measurements of a mold when making CP soaps?
thanks
shirley
Hi Shirley, you can either purchase molds that are specifically for a soap recipe size or you can work it out manually. You do this by measuring the volume of your mold in cubic inches (L x W x H). The number you get will be the total volume of the mold in oz. Soap recipes are measured by the main soaping oils though (not the water or other ingredients), so multiply the total volume number by 0.4 to get the soap recipe size in oz. This is the number you’d plug into the SoapCalc as the final recipe size.
Hi Tanya. My question is about what type of skin is suitable for this recipe?
Hi Elvira, this is for an average skin type to slightly oily
Hi Tanya! Thanks so much for your wonderful website and soap recipes. I love the detailed explanations and breakdowns of everything!!
A question about the essential oils in this recipe: I see all three show 3/4 tsp or 3.4g, besides for the Peppermint oil which also shows 3/4 tsp, but 3.7g? Is this correct?
I’m probably being too technical but know how important each gram is. Thanks!!
Yes, it’s correct. Essential oils can weigh different amounts for the same volume.
Hi There.
Can I ask what colour was used and how much? Also, was it added to oils or at trace?
Great recipe that I’m going to try.
Thanks.
Hi Tracy, the green colorant is listed with the liquid oils, and the method of use is given in the instructions.
Thanks so much for the recipes! My first batch came out perfectly.
Just the second batch went not that well. The next morning it was allready completely hard and I can’t cut it, it falls apart. I used the above recipe with the exact same amount of ingredients. Just I used 1 teaspoon of curcuma in the lye, in stead of the color above. Do you know why it became so hard?
I can’t find out what I did wrong. Thanks so much!
Hi Lotti, I’m not sure what went wrong when you changed the recipe, but I’m glad that when you made it as described, that the batch turned out perfectly :)
Recipe Looks lovely and the color :). My only concern is the soap might be quite drying due to large amount of oconut oil, also did it last long ? as you don’t have any longevity oils such as cocoa butter or palm oils, etc. Was that a case? I’m always on a lookout for new recipes without palm oil. Thank you so much.
It’s not drying, so that shouldn’t be a concern. I would not have shared the recipe otherwise. As for longevity, it’s different based on your specific choice of ingredients. If you use a bottle of olive oil that expires next month then that’s how long your soap is good for. However, the maximum shelf-life of this soap, and any others with herbs mixed in, is one year.
Just getting started into the world of soapmaking and really appreciate the great instruction and small batch recipes you have. As a general question will leaving out the essential oils in a recipe affect the soap? Do you have to make any adjustments to the recipe to account for no essential oils? Thanks much!
Love all the gorgeous soap recipes in Lovely Greens. First time making soap followed your Calendula Soap recipe two weeks ago and it looks pretty good. Now it’s the waiting game. The recipe uses coconut oil, shea butter, olive oil and castor oil.
This Herbal Soap uses the above 4 oil +
sunflower oil and sweet almond oil. You recommend using single base receipt so we know what to expect each time, able to spot any difference and save money. I m thinking whether to use the calendula recipe or herbal recipe as my single base recipe. Wanna make floral or herbal and maybe some soap for Christmas. Could you please give me a suggestion and what’s the difference of these two recipes. Thank you in advance.
Is there an alternative option that I could substitute for the coconut oil? I have an allergy to coconut.
Unfortunately most handmade soap is made with coconut oil and it cannot be substituted in this recipe. If you’d like to make a coconut-free recipe, try this olive oil soap: https://lovelygreens.com/simple-castile-soap-recipe-make-olive-oil-soap/
First time making soap, read a couple of books and took a class but I love your recipes they always turned out perfect. Made 57 bars of soap for wedding shower favors and everyone loved them.
I really enjoy your newsletter and have recommended it to friends.
Whoo hoo! That’s amazing :) Hope everyone enjoys your handmade soap