How to make Natural Lemongrass Soap

How to Make Natural Soap with Lemongrass Essential Oil
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Make Natural Soap with Lemongrass Essential Oil

This simple recipe for handmade lemongrass soap requires only four main oils, natural pigment in the form of oxides, essential oil, and a few other ingredients and materials. It’s also a palm-free soap recipe so you can rest assured that the ingredients are as ethical as possible.

Making cold-process soap is quick but there is a cure time of four weeks before you can use the bars. During that curing time, the extra water from the recipe evaporates out, creating hard and long-lasting bars. The DIY tutorial for this recipe is below as well as the video instructions.

Lemongrass Soap Recipe

800g batch — 1.76lbs (refers to oil content)
Makes approx. 8 bars & fits in this silicone loaf mould
Technical info: 6% superfat and using water as 25% of the oil content

Lye Water
109g/ 3.8oz Sodium hydroxide (also called Lye or Caustic Soda)
196g / 7 oz Water

Solid Oils
200g / 7oz Coconut Oil
150g / 5oz Shea Butter

Liquid Oils
400g / 14oz Olive oil (or Olive oil Pomace)
50g / 1.76oz Castor oil
1/16 tsp Yellow Iron Oxide
1/16 tsp Chromium Green Oxide

Add at Trace
8 drops Grapefruit Seed Extract
4 tsp Lemongrass Essential oil

Special Equipment needed
Digital Thermometer
Digital Kitchen Scale
Stick (Immersion) Blender

How to Make Natural Soap with Lemongrass Essential Oil

Natural Soapmaking for Beginners Series

If you’d like to learn more about making natural soap, read through my four-part free soap making series. They include background on soap making ingredients, equipment, safety precautions, basic recipes, and the full process of making soap. Continue below for instructions for this recipe.

1. Ingredients
2. Equipment & Safety
3. Basic Recipes and Formulating Your Own
4. The Soap Making Process: Make, Mould, and Cure

How to Make Natural Soap with Lemongrass Essential Oil

The soap at ‘Trace’

Step 1: Measure your Ingredients

It helps to be prepared so have all of your ingredients measured and your equipment and work space set up. Get goggles on, latex/vinyl/rubber gloves on, tie your hair back, and make sure that you’ll be able to work undistracted. Also, measure all of your solid oils into the pan and your liquid oils into a jug.

Step 2: Mix your Coloured Oil

Pour a Tablespoon of liquid oil (olive oil) into a glass and then add in the mineral powder. Blend it with a milk frother until it’s thoroughly mixed. Set aside for now.

How to Make Natural Soap with Lemongrass Essential Oil

Step 3: Mix your Lye Solution

This is the step that you need to take the most precaution. Pour the Sodium hydroxide (lye) crystals into the water in a well ventilated space. Mix together with a stainless steel spoon until the crystals are dissolved. There will be heat and steam — try to avoid both. The jug will get quite hot on the bottom and keep your face well away from the fumes. When mixed, set the jug of hot lye solution in a basin of water to cool.

Step 4: Heat your Solid Oils

On very low heat, melt your solid oils until there are just a few solid bits floating around. Take the pan off the heat and stir until the oils are melted.

Step 5: Add the Liquid Oils

Pour the liquid oil and coloured oil through a sieve and into the melted oils. The sieve stops chunks of colour from getting into the soap. Also take care to scrape the castor oil out of the jug and into your pan. It’s very sticky so your rubber spatula comes in handy.

How to Make Natural Soap with Lemongrass Essential Oil

Step 6: Take the Temperature

Take the temperature of both the oils in the pan and the lye solution. The oils should be within 110-130°F and the lye solution should be within ten degrees of the oil’s temperature but lower than 130°F. When they’re just right, pour the lye solution into the pan through the sieve.

Step 7: Bring to Trace

Using your stick blender, alternate pulsing and stirring until you hit ‘Trace’. This is when your soap batter thickens enough that if you lift the stick blender out, the dribbles will hang around on the surface. The video shows my method for pulsing and stirring and also what Trace looks like. Try to keep the blender’s head on the bottom of the pan to minimize air and splattering.

Step 8: Fragrance

When Trace is met, measure in the Grapefruit seed extract and essential oil. Stir well and then pour the soap into the mould. If you don’t stir well enough the essential oil will leave streaks in your soap. Not a huge deal when it comes to function but it doesn’t look great.

Step 9: Insulate

Slide your moulded soap into a cardboard box and close it up. Cover the outside with a towel to keep the heat in. Drafts will cause the soap to cool quicker causing the end colour to not be as vibrant.

Step 10: Cutting & Curing

After 24 hours you can pop the soap out of the mould and cut it up using a kitchen knife or thin metal wire. Afterwards, space your bars out on a piece of wax paper in an airy place that’s out of direct sunlight. Leave the soap there to ‘Cure’ for four weeks before using. This time allows the water content in the soap to evaporate out.

When that month is up, your handmade Lemongrass Soap is ready to be used. To preserve the scent, store your bars in a sealed tub after the curing time is up.

13 Discussion to this post

  1. Camille says:

    I don’t have the mineral powders but I really want to make this soap. Can they simply be omitted?

  2. Tom says:

    Hello I am new to the soap making process actually never made it before. Yesterday l made the Lemon grass soap and it looks like it turned out, and the smell coming from the curing box is very nice. I do have one comment could you look at the recipe the water measurements do not add up, it calls for 10.7 oz or 196 g of water well 10.7 oz is actually 303 grams. Which number do you follow i used the 196 grams of water and it looks like it turned out

    • lovelygreens says:

      Oh dear! Yes that was a typo — I always use grams and the oz amount was incorrect. THANK YOU. If anyone made the recipe with the larger amount it’s not a big deal — it will just need the full four weeks to cure (to allow the water to evaporate out)

  3. lacey says:

    Hello there!

    I attempted this soap and came up with some pretty weird results. I measured everything precisely, and followed the temperature suggestions, but I ended up with a jelly-like substance that absolutely won’t harden up. It’s like a mix between mashed potatoes and olive oil, a big gloppy jelly. Any idea what I may have done wrong? Or if I can do anything to fix it? Thank you for your time! Any suggestions would be much appreciated.

    • lacey says:

      Mystery solved! Just realized I’ve been using potassium hydroxide instead of sodium hydroxide. Doh! What a waste. But a good learning experience 🙂

      • lovelygreens says:

        Yes, Potassium hydroxide is also a soaping ingredient — but for making liquid soap and in a completely different process. Good luck with your second attempt!

  4. Dana says:

    do you have a substitute for grapefruit seed extract?

  5. Heather R says:

    What is the superfat of this recipe? And does it lather well? Thanks!

  6. Claudia. Mazurkiewicz says:

    What does the lye add to the soap? Can you make this receip without the lye?

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