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5 from 15 votes

Natural Rosemary Cold-Process Soap Recipe

How to make rosemary soap with essential oil, rosemary leaves, and Cambrian blue clay. This recipe is high in olive oil and may come out quite soft at first. You can leave it in the cavity molds until it firms up, though. If you use extra virgin olive oil in the recipe, expect your bars to turn a soft grey-green. If you’re using a lighter-colored olive oil pomace, the color will be bluer. 1 lb (454 g) batch with a 5% superfat — makes six standard-sized bars. The full video instruction on making this soap is at the bottom of this piece.
Course Soap recipe
Cuisine Herbal soap
Keyword soap, soap recipe
Prep Time 30 minutes
Cook Time 45 minutes
Curing time 28 days
Total Time 28 days 1 hour 15 minutes
Servings 6 bars
Author Lovely Greens
Cost 20

Equipment

Ingredients

Lye solution

Clay mixture

  • 2 tsp Cambrian blue clay 3 g / use another colored clay if you wish
  • 6 tsp distilled water 30 g

Solid oils

Liquid oils

Add after trace

To prevent soda ash

Instructions

Prepare your Soap Making Station

  • Cold-process soapmaking is chemistry, and this recipe uses lye. Lye is a caustic substance that is completely neutralized in the soapmaking process, but it can be harmful if not handled correctly. Please read this soap making safety guidance before proceeding.
  • Ensure that your kitchen workspace is clean and set up with all of your tools, ingredients, and equipment. Please also prepare yourself by wearing long sleeves, closed-toe shoes, goggles, and plastic gloves. Soap making is fun but also chemistry so you need to work safely.

Make the Lye Solution

  • A couple of hours before you make soap, put on your goggles and gloves, and make the lye solution. You should do this in a well-ventilated area and try not to breathe in the steam. Measure the sodium hydroxide (lye) into a container and the distilled water into a heat-proof jug.
  • Pour the sodium hydroxide into the water and stir very well. It will be very hot at this point, so be careful. Set the jug somewhere safe and leave the lye mixture to cool to just above room temperature 27 °C (80 °F).

Prep Work

  • While the lye solution is cooling, measure the solid oils in the pan and the liquid oils in a jug.
  • Finely chop the rosemary. Fresh leaves are better for this recipe, but dried is fine. The rosemary pieces eventually add dark, dried specks to your bars and you can feel them as you use the soap. If they're not small, they may feel scratchy. You can also make this recipe without the rosemary leaves if you wish.
  • In a ramekin, mix the clay with the extra water. The extra water amount helps mix the clay into the soap batter and it also stops the clay from making your soap crack.

Melt the Solid Oils

  • When the lye solution is room temperature, stir in the sodium lactate. The amount listed is for liquid sodium lactate so if you're using powdered sodium lactate, just use half the amount given.
  • Place the pan of solid oils on the hob and turn it on to the lowest heat setting. They will melt quicker than you expect, so stay with the pan, moving the oil around in the pan to help speed up melting. When there are a few small pieces of solid oil still floating, take the pan off the heat and set it on a potholder. They'll melt with the residual heat and some gentle stirring with your spoon/spatula.

Add the liquid oils and clay

  • When the solid oils are fully melted, pour the liquid oils into the pan of melted oils. To minimize air bubbles getting in, try pouring the liquid oils onto a clean spatula held over the pan of oils. Use the spatula to get every last drop out of the jug then stir the oils together gently.
  • Next, pour the clay mixture into the pan. Use a spatula to scrape all the color out of the container and into the pan. Don't be alarmed if you see blobs of color at the bottom of the pan.
  • Take the temperature of the pan of mixed oils and clay. You're aiming for around the same temperature as the lye solution, but they can be a few degrees higher of 27 °C (80 °F). If they're too hot, floating the pan in cool water whilst stirring helps to cool them quickly.

Bringing the Ingredients to 'Trace'

  • When the temperatures are right, pour the lye solution through the sieve and into the pan of oils.
  • Carefully place the head of the immersion blender (stick blender) into the oils. Insert it at an angle so that any air inside the head can escape as you submerge the head. Air trapped inside the head can create air bubbles in your soap.
  • The next step, bringing the ingredients to trace, is best shown in the video at the bottom of this recipe. Have a watch to understand all the steps better, but especially this one.
  • Stir the contents of the pan gently, using the immersion blender as a spoon. Then bring it into the center of the pan and hold it against the bottom of the pan. Not moving the immersion blender, pulse for a couple of seconds. Then gently stir. Keep repeating this pulse then stir process until the soap thickens to a light to medium trace. You'll see just the faintest trace marks on the surface of the soap and it will still be pourable. Stop blending, tap off the immersion blender's head, and put it aside. You will not use it again.

After Trace

  • Add the rosemary essential oil and gently stir with a spatula until completely mixed in.
  • Sprinkle the chopped rosemary into the soap batter and gently stir it in.

Molding and Curing

  • Pour the soap batter into your mold(s), generously spray the surface with the rubbing alcohol (isopropyl alcohol), and set the soap aside. Come back again after fifteen minutes and spray the surfaces again -- the alcohol creates a barrier on the soap and helps stop soda ash from forming.
  • Leave the soap to harden inside the mold for at least 48 hours before taking it out. It may be a little sticky, and if this is the case, you can leave the soap in the mold for longer, even a week or more. You can also put the entire mold in the freezer for 30 minutes to an hour. They should pop out easily after that.
  • Next, find someplace in the house that's safe from animals and kids and that is airy and out of direct sunlight. Lay a piece of baking paper down and space your bars of soap out over it. You should leave your soap there for four weeks to allow excess water to evaporate out of your soap and for them to fully harden up. This is called curing soap.
  • This soap's lather is stable and creamy and its color will be grey-green to grey-blue. When fully cured, you can begin using the soap and gifting it to others. It has a shelf life of up to two years.

Notes

Another way to mix the clay into this recipe is to add the clay to the lye solution. If you do this, you won't need the extra water amount for mixing the clay in this recipe. Make sure to stir well.
Lastly, are you a beginner soapmaker looking for more guidance on how to make handmade soap? Enroll in the Natural Soapmaking for Beginners Online Course to get up to speed quickly. You'll learn all about soap ingredients and equipment and be guided through step-by-step soap recipe videos. Learn more