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Cold Process All-Natural Handmade Soap

If you have ever been curious about the world of handmade soap, chances are you have heard of cold process soap. This type of soap making produces an artisanal-looking handmade soap that can be scented with natural essential oils and botanical elements. Grab a few friends and learn how to make soap!

Stack of handmade cold process soap

Cold-process soap is part science and part art. You certainly will need to follow the step by step directions carefully, but if you do, you can produce the most lovely bars scented with essential oils and colored with botanical elements. These handmade soap bars are a project you can make at home that looks like it came from an artist’s gallery. Plus, cold-process soap has no additives that are bad for the earth and it is gentle on sensitive skin.

How to Make Soap for Sensitive Skin

Many bath and body “soaps” that are commonly sold are not actually soap. You will notice that they are called a beauty bar or body wash. These are detergents, not soap.

Real soap (such as the cold process soap in this tutorial) goes through the saponification process. This is a fancy term for converting fats, oils, lye, and water into soap and glycerin. After the chemical process has completed, the soap is completely safe and gentle on skin.

Even better, the glycerin coats skin and gives skin a silky soft feeling.

Handmade Soap Methods

There are many methods to making handmade soap such as melt and pour, cold process, hot process, milk soap, and rebatching.

There are pros and cons to each of these methods. I have made soap all of these ways, and each produces a very different type of soap.

Personally, I like the hot process method for making beer, wine, and tea soaps. I melt and pour for quickly making fun, decorative soaps which you can see some examples of in my melt and pour soap idea book, Good Clean Fun.

Good Clean Fun soap making book

How to Make Cold Process Soap

I like cold-process soap most as my everyday soap. I usually make soap in big batches every year so I have plenty to choose from throughout the year and plenty more to give away.

Cold-process soap makes a wonderful gift for yourself and others, but it does require following the instructions to the letter. If you are a first-time soap maker, partner with a friend and make handmade soap together – it helps to have a buddy system and it’s a lot of fun! If you are are an experienced soaper, there are three recipes down at the end for the soap shown in this post:

  • Lemongrass Ginger Coffee Kitchen Soap
  • Rosemary Spearmint Energizing Shower Soap
  • Orange Vanilla Cinnamon Soap

All are made with natural vegetable ingredients, pure essential oils, natural colors, and herbs from the garden. You can feel good about taking care of those who use your handmade soap.

Ingredients

All cold process soap will have fats and lye ingredients. Start with a basic soap-making recipe such as this moisturizing olive oil soap.

Mix temp 115°F

Oils

Lye mixture

Want something even easier? Well, you can use a pre-weighed soap-making kit, like this Natural Soap-Making Kit or this Shea Butter Soap-Making Kit.

Step by Step Soap Making Instructions

If you are not using a kit, the first and most crucial step in cold-process soap making is to weigh the raw ingredients (fats, lye, water) precisely. Prep everything that you will need and lay it out accessibly before you begin.

Soapmaking measurements are done in weight, not volume, so be sure to get a good kitchen scale and weigh out the ingredients.

weighing out cold process soap supplies

Safety reminder: It’s best to wear protection when making soap as lye can burn your skin. Until the oils and lye have turned into soap (48 hours after making the recipe) it’s best to protect yourself. Always wear rubber gloves, safety goggles, and keep your work area free from kids and pets.

Heat the Oils

Gently (slowly) heat oils in a stainless steel pot on the stove. Alternatively, use a microwave and heat for two minutes on high, and then at shorter intervals until you reach the temperature listed in the recipe.

Prepare Lye Ingredients

Using room-temperature distilled water, weigh the amount specified by the formula into a heat-resistant glass bowl or large Pyrex measuring cup. While stirring, slowly add the measured amount of lye. I repeat, SLOWLY.

It’s important to note that you add the lye to the water, not the water to the lye.

Stir until dissolved. This mixture will get super hot quickly so be mindful of that. Also, the fumes are terrible, so if you can stir from below the fumes (with lye on the counter and you crouching below as you stir) outdoors or at least with windows open, that would be best.

Place glass container in an ice-water bath and cool to the required temperature. For this basic recipe, it’s 115 degrees. Get accurate temperature readings with a candy thermometer in the middle of the solution.

When both oils and lye/water are at the required temperatures (as stated in your recipe), slowly pour lye/water into the oils while rapidly stirring in small circles. Always add lye/water to oil, not the other way around.Stirring cold process soap ingredients together into a thick mixture

Thicken the Mixture

Continue to rapidly stir the mixture until it thickens to the consistency of pudding (called “tracing”). The mixture is ready to be molded when a drizzle mark from the spatula remains for a few seconds on the top of the mixture. Speed up the tracing process by using a hand blender to mix. Be careful not to over mix.

Add Essential Oils and Colorants

Add essential oils, natural colorants, and herbs or exfoliants at this stage (see recipes below). Work fast as the mixture will quickly start to thicken.

There are many options for coloring and scenting soap but I avoid perfumes, fragrance, and artificial colors. I like handmade natural soap scented with pure essential oils and colored with natural dyes.

As you can see by these three recipes, it looks beautiful and it smells even better!

Pour into Mold

Pour mixture into 1L milk cartons and staple the tops shut. Wrap the cartons in a large towel and set somewhere warm for 48 hours like the top of the fridge. The cartons will feel warm and will get hot as the mixture neutralizes and turns into soap.

Cold process soap in a milk carton mold

Unmold and Cut

To unmold your soap, peel off the milk cartons and cut each full 1-liter carton lengthwise into 3 equal sections for shower soap, and 4 equal sections for hand soap. Flip each section so that it appears to be a square from the top, and cut into 3 equal sections.Freshly unmolded soap in 3 colors before being cut

Cure

Place each bar on a wire rack in a cool, dark place to cure for three weeks. After three weeks, soap can be buffed with a cotton cloth and wrapped for gifts.

Cold Process Soap Add-ins to Try

Once you get the basic recipe down, you will find that it’s incredibly versatile! Here are just a few ways you can “dress up” cold process soap.

Lemongrass, Ginger, and Coffee Kitchen Soap

  • Add 1 tablespoon dry, finely ground coffee at trace
  • Scent with 15ml lemongrass and 5ml ginger essential oils
  • Color with turmeric

To get the two-toned look in this soap, I filled half of the milk carton with one color and topped it with another. This makes each of the bars unique. The purple in the above soap was lavender-scented soap colored with ratan jot and mixed with dried lavender buds.

cold process soap with botanicals and essential oils added in

Rosemary and Spearmint Energizing Shower Soap

To get the two-toned look in this soap, I filled half of the milk carton with one color and topped it with another. This makes each of the bars unique.

handmade soap with rosemary and spearmint

Orange Vanilla Cinnamon Soap

  • Add 1 tablespoon dry, finely ground coffee at trace
  • Scent with 7ml orange, 7ml cinnamon, and 7ml vanilla essential oils
  • Color with cinnamon
  • Gently stir in cocoa powder to make a chocolate color swirl
  • Top with dried saffron

Bar of homemade soap topped with saffron

 

Resources to Learn More About How to Make Soap

stacks of handmade soap made with cold process

Perhaps there is another recipe you would like to try? There are a lot of great soap-making recipe books:

And, of course, my own book on handmade soap the easy way (using the Melt and Pour Method): Good Clean Fun

Even More Handmade Soap Recipes to Try:

How to Make Cold Process Soap

This handmade soap recipe will show you exactly how to make a batch of cold process soap at home.

Equipment

  • Kitchen scale

Supplies

Oil Materials

Lye Materials

  • 78 grams sodium hydroxide (NaOH)
  • 215 grams filtered/distilled water room temperature

Instructions

  • Weigh and measure every ingredient ahead of time. It is imperative that items are weighted and measured precisely.
  • Wear gloves and safety goggles, and keep your workspace clean - lye can burn skin.
  • Heat the oil ingredients slowly in a stainless steel pot until you reach a temperature of 115 degrees.
  • Pour the room-temperature water into a large pyrex measuring cup. Stir, and SLOWLY add the pre-weighed lye. It's important to note that you will add lye to the water, not the other way around.
  • Stir until dissolved. Then place the glass container in an ice bath and cool to 115 degrees.
  • When the oils and lye mixtures are both at 115 degrees, slowly pour the lye into the oil mixture while rapidly stirring in circles.
  • Stir until the mixture becomes thick, and similar to the texture of pudding.
  • Add in the botanicals and/or essential oils - see the blog post for ideas.
  • Pour the mixture into molds (I use 1L milk cartons), and staple the tops shut. Then, wrap the molds in a towel and set on top of the fridge for 48 hours.
  • Unmold the soap and cut into even sections. Then, place the bars on a wire rack and let them cure for 3 weeks.
  • Buff with a cotton cloth, and wrap to give as gifts or use yourself!

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