Cold Process Soap Making Guide

Throughout this guide, we are going to explain the entire cold soap-making process from start to finish. By the end, you will have learned everything you need to know about creating your own unique and beautifully handcrafted soaps, completely from scratch.

Whether you are a complete soap-making novice or an expert you'll definitely learn something new about how to make soap at home.

The first thing you must do is understand what soap is. This is absolutely vital in learning cold process soap making. Please see our What is Soap? article before continuing which you can find linked here.

Cold Process Soap Making Ingredients

Now you are fully informed on what soap is, and how it is made, it’s time to gather your ingredients:

Soap Making Oils

Sodium Hydroxide

Essential Oils

Fragrances

Colourants

Soap Moulds

Two Large Soap Making Pots

Thermometer

Scales

Large Soap Cutter

Best Essential Oils for Cold Process Soap

When it comes to cold-process soap making, choosing the right essential oils is essential for creating fragrant, long-lasting, and skin-friendly soaps. The best essential oils for cold-process soap making are those that have good scent retention, are skin-safe, and blend well together. Here are some popular essential oils for soap making:

Lavender: Lavender essential oil is a favourite in soap making due to its calming and soothing properties. It pairs well with other essential oils and is gentle on the skin.

Peppermint: Peppermint essential oil provides a refreshing, invigorating scent. It's great for awakening the senses and is often used in combination with other essential oils.

Eucalyptus: Eucalyptus essential oil has a clean, medicinal aroma and is known for its respiratory benefits. It blends nicely with citrus oils or lavender.

Tea Tree: Tea tree essential oil is prized for its antiseptic and antibacterial properties. It's an excellent choice for soaps designed for acne-prone or problem skin.

Lemongrass: Lemongrass essential oil offers a bright, citrusy scent. It's uplifting and can add a zesty twist to your soap.

Sweet Orange: Sweet orange essential oil has a cheerful, fruity scent. It blends well with other citrus oils and warm, spicy scents like cinnamon.

Patchouli: Patchouli essential oil has a rich, earthy aroma. It's often used in soaps for its grounding and balancing properties.

Rosemary: Rosemary essential oil has a fresh, herbal scent and is believed to have cognitive and memory-boosting benefits.

Geranium: Geranium essential oil has a floral and slightly sweet aroma. It's used for its skin-balancing and mood-enhancing qualities.

Cedarwood: Cedarwood essential oil has a woody, grounding fragrance. It's a popular choice for men's and earthy-scented soaps. Frankincense: Frankincense essential oil has a warm, resinous scent and is known for its calming and grounding properties.

Ylang Ylang: Ylang-ylang essential oil has a sweet and floral aroma. It's often used in romantic or exotic soap blends.

Remember to consider the potential sensitivities or allergies of those who will use your soap, and perform a skin patch test when trying new essential oil combinations. Also, use essential oils sparingly as they can be potent, and be aware that some essential oils may accelerate the trace in your soap recipe, causing it to thicken more quickly. Always follow safety guidelines and recommended usage rates for each essential oil when making cold-process soap.

Best Colourants for Cold Process Soap

When it comes to colouring cold-process soap, there are various options to choose from, including natural ingredients and synthetic colourants. The best colourants for cold-process soap making depend on your preferences, desired results, and the type of soap you're creating. Here are some popular options:

1. Natural Colourants: Clays: Kaolin clay, French green clay, and rose clay can be used to provide natural colouring and additional skin benefits. Click here to shop Natural Colourants.

Activated Charcoal: Provides a black or dark grey colour and is often used for detoxifying or facial soaps. Click here to shop Activated Charcoal.

2. Oxides and Ultramarines: These are synthetic colourants that are commonly used in soap making because they produce vibrant and consistent colours. Common options include titanium dioxide (for white), iron oxides, and ultramarines. Click here to shop synthetic colourants.

3. Micas: Mica powders come in a wide range of colours and offer a shimmery or metallic effect. They are popular for creating vibrant and eye-catching designs in soap.

4. Pigments: Soap-safe pigments are available in a variety of colours and can be used to achieve bold and long-lasting colouration in cold-process soap.

5. Liquid Soap Colorants: Liquid colourants, like water-soluble dyes, can be used to create intricate designs or swirl patterns in soap.

Click here to shop all colourants.

When choosing colourants for your cold-process soap, keep the following tips in mind:

Stability: Consider the stability of the colourant in your soap recipe. Some natural colourants may fade over time, while synthetic colourants tend to remain stable.

Skin Safety: Ensure that the colourants you choose are safe for skin contact and do not cause skin irritations or allergies.

Opacity: Different colorants have varying levels of opacity. Some will provide a more translucent colour, while others will be more opaque.

Usage Rate: Follow the recommended usage rates for colourants to avoid over-colouring your soap, which can lead to staining or skin irritation.

Testing: Always perform colour tests and small-batch experiments to see how your chosen colourants behave in your specific soap recipe.

Regulations: Be aware of any regulations regarding the use of colourants in cosmetics and soap products, as they may vary by region.

Ultimately, the choice of colourant depends on your soap-making goals, aesthetic preferences, and the specific characteristics you want to achieve in your final soap products.

How to make Cold Process Soap

The most enjoyable experience about cold process soap making is you choose from start to finish exactly what goes into your product, so the ingredients you chose are completely unique to you! Once you have your equipment ready, be sure to wear protective gloves and goggles throughout the entire process as you will be handling harmful chemicals which can lead to serious injury.

1.Preparing your Lye Solution: Measure out with total accuracy your sodium hydroxide (Lye) according to your recipe or see our saponification table, with the exact amount of water. If your soap recipe doesn’t state how much water to use, the general rule is 3 parts water to 1 part lye. Make sure you do not use hard water in cold process soap making as the unwanted chemicals in the water could react and ruin your soap. If you have hard water, we recommend either purchasing a water softener or simply buying distilled water. Once you are ready with the exact amount of Lye and water, add the lye to the water in the soap-making pot (not water to lye!) and begin mixing until the lye has fully dissolved. The reaction alone will reach temperatures up to 93°C so make sure your chosen pot can withstand those temperatures. Be warned, if you add too much water, the finished soap can become too soft, whereas with too little water the soap can become too caustic and dry. Your recipe will specify what temperature the lye should be to combine with the oil, so leave to cool and check the temperature regularly. The usual temperature is 35°C.

2.Preparing your Oils: Now add your carefully measured liquid oils to a separate soap-making pot and stir. If you have chosen to use solid oils, melt them carefully using a microwave or hob and pour with the rest of the oils to slightly above their melt point (typically 35°C). Remember, it is crucial to use the correct measurements of lye and oil, too little oil and the soap will be too hard and caustic, too much and it will be too soft. Now insert your second thermometer into the oil mixture checking regularly until reaching the desired temperature.

3.Saponification: Now wait for your lye and oil solution to reach the desired temperatures; you can speed up the process by placing the soap-making pots in hot or cold water. Once both pots have met their desired temperatures, pour the oils and fats mixture slowly into the lye solution and stir vigorously in Figure eight to ensure all the necessary molecules are interacting. You can test the mixture by drizzling the mixture from the mixing spoon on the surface of the liquid, if it floats for a brief period and then sinks back into the solution saponification has taken place. This is called the ‘Trace’ stage. Keep stirring for anything from 45 minutes to an hour, though the ‘Trace’ stage can vary greatly from different oils used or if a handheld blender has been used to the time is greatly reduced.

4.Personalise: Once you are in the ‘trace’ stage, it is now time to add your essential oils, fragrances, colours and exfoliants. Stir thoroughly until the mixture is even throughout, and pour into your desired soap mould. Cover the mould with towels or any other insulating material to maintain as much heat as possible, this is essential for the curing process. Now leave the soap to cool for 18 – 36 hours, depending on the ingredients used.

5.Curing: Once your soap has solidified, slice your bars into the desired thickness, or alternatively trim and carve the soap into your desired shapes. If you have used individual moulds, take out your finished bar, and place the shaped soap onto a rack to allow air to circulate around it, turning them over once every 6 to 8 days. Depending on the recipe, the curing process can take anything from 3 to 8 weeks; this allows the pH level to drop to a mild and homemade soap bar. Once the curing period is over, scrape off any residual white powder (soda ash) on the surface of the bars, as the substance can be harmful to the skin.

Congratulations! You have now successfully created your very own handmade soap bars from scratch. Don’t forget to add any decorative packaging or ribbons to finish off the truly handmade look! Happy Soap Making!

Cold Process Soap Benefits

Cold process soap making is a traditional method of creating soap by mixing oils, lye (sodium hydroxide), and water. The process does not involve external heat sources, which allows the soap to cure naturally over time. Here are some of the benefits of cold-processed soap:

Control Over Ingredients: Cold process soap makers have complete control over the ingredients used in their soap. This allows for customisation of the soap to suit specific skin types and desired properties.

Natural Ingredients: Many cold process soap makers use natural and organic ingredients, such as plant-based oils, butters, and essential oils, which can be beneficial for the skin and the environment.

Glycerin Retention: Cold process soap retains its natural glycerin content, a humectant that attracts moisture to the skin. This can help keep the skin hydrated and soft.

Customisation: Cold process soap can be customised in terms of colour, fragrance, and design. Makers can create unique and artistic soap bars by incorporating various colorants, essential oils, and swirling techniques.

Long-Lasting: Well-made cold process soap tends to be hard and long-lasting. It doesn't dissolve quickly in water, which means it can be used for an extended period.

Skin-Friendly: When formulated with skin-loving ingredients, cold process soap is gentle on the skin and can be tailored for specific skin conditions, such as sensitive, dry, or oily skin.

Sustainability: Many cold process soap makers focus on sustainability by using responsibly sourced ingredients and reducing packaging waste.

Artisanal Craftsmanship: Cold process soap making is often considered an art form. Makers take pride in creating unique, handcrafted products that stand out from mass-produced soaps.

Educational Experience: Making cold process soap can be a rewarding and educational hobby or business. It allows individuals to learn about the chemistry of soap making and experiment with different formulations.

Minimal Chemical Additives: Cold process soap typically contains fewer synthetic additives and preservatives compared to some commercial soaps. This can be appealing to individuals who prefer more natural and simple skincare products.

No Need for Harsh Surfactants: Cold process soap relies on the saponification process, which transforms oils and lye into soap. This eliminates the need for harsh surfactants like sulfates often found in commercial soap products.

Scent Variety: The use of essential oils allows for a wide variety of scent options, making it easy to create personalised fragrances.

It's important to note that cold process soap making involves working with lye, a caustic substance. Proper safety precautions, including wearing protective gear and working in a well-ventilated area, are essential when making cold process soap. Additionally, soap should be allowed to cure for several weeks before use to ensure that the lye has completely saponified, making the soap safe for the skin.

Cold Process Soap FAQs

What is cold process soap? Cold process soap is a method of soap making that involves creating soap from scratch using a chemical reaction between oils or fats and an alkali, typically sodium hydroxide (lye), and water. The term "cold process" refers to the fact that no external heat source is required during the saponification process, which is the chemical reaction that transforms the oils and lye into soap.

Can you melt cold process soap? No, you should not melt cold process soap once it has gone through the saponification process and has cured. Cold process soap is a result of a chemical reaction between oils or fats and an alkali (usually sodium hydroxide or lye) in the presence of water. This reaction, known as saponification, transforms these ingredients into soap and glycerin. Melted cold process soap can lose its structural integrity, and the properties that make it a solid bar of soap may be compromised. Additionally, reheating or melting the soap can cause the scent to dissipate and may result in an uneven texture or color. If you want to reformulate or create a new batch of soap, it's best to start from scratch with a new recipe and ingredients. This way, you can maintain the quality and characteristics of your soap. However, if you have small pieces or scraps of cured cold process soap that you'd like to reuse, you can grate or chop them into small pieces and incorporate them into a new batch of soap during the soap-making process to create a "confetti" soap or to add a unique texture to your new bars.

How long does cold process soap take to cure? The curing time for cold process soap typically ranges from 4 to 6 weeks, although some soap makers may recommend even longer curing periods for optimal results. During this curing period, the soap undergoes several important changes that improve its quality and performance:

Saponification Completion: While the chemical reaction known as saponification starts immediately upon mixing the oils and lye, it continues during the curing process. All the lye must fully react with the oils to ensure the soap is safe for use.

Water Evaporation: As the soap cures, water evaporates from the soap, making it harder and longer-lasting.

Mildness: The longer the curing period, the milder the soap becomes. A longer curing time allows any residual lye to completely neutralise, resulting in a gentler, less harsh soap.

Firmness: The soap hardens and becomes more durable over time, making it easier to handle and use. Scent Stabilization: Curing helps stabilise the fragrance in the soap. During the initial curing phase, the scent may be strong, but over time, it mellows and becomes more balanced.

Moisture Content: Curing allows the soap's moisture content to stabilise, preventing it from becoming overly soft or prone to rapid melting when used. During the curing period, it's important to store the soap in a cool, dry, and well-ventilated area. Keep the soap bars on a drying rack or a grid to allow air circulation and prevent them from sticking to surfaces. Also, ensure that the soap bars are not in direct contact with one another, as this can help them cure evenly. Once the curing period is complete, the soap is ready for use, and it will be milder, harder, and provide a better lather. However, many soap makers find that their soap continues to improve with extended curing, so if you have the patience, allowing it to cure for a few months can yield even better results.

How should you store cold process soap? Storing cold process soap properly is essential to maintain its quality and prolong its shelf life. Here are some guidelines on how to store cold process soap: Ventilation: Allow air circulation around your soap. Store it in a cool, dry place with good ventilation. Avoid airtight or humid conditions, as these can cause moisture buildup, which may lead to "sweating" or a softening of the soap's surface. Soap Dish or Rack: Place your soap on a soap dish or rack that allows it to drain and dry between uses. This prevents the soap from sitting in water or moisture, which can lead to premature melting and a shorter lifespan.

Avoid Direct Sunlight: Keep your soap out of direct sunlight. Prolonged exposure to sunlight can cause the soap's colors to fade and may affect its fragrance.

Separate Bars: If you're storing multiple bars, make sure they don't touch each other. Stacking or clustering soap bars can trap moisture between them, potentially causing them to stick together or develop a "mushy" texture.

Wrap or Cover: While proper ventilation is important, you may want to wrap your soap to protect it from dust and debris. Use wax paper, kraft paper, or breathable fabric bags to cover the soap.

Fragrance Protection: If you have multiple soap bars with different fragrances, it's best to keep them in separate containers or bags to prevent the scents from mingling.

Labelling: Label your soap with the date it was made. This helps you keep track of curing times and ensures you use the oldest bars first.


Storage Containers: If you're storing soap for an extended period, consider using a container with good ventilation, such as a cardboard box or a mesh bag. Plastic containers may trap moisture.

Cool and Dry: Keep your soap away from extreme temperatures and humidity. Avoid storing soap in the bathroom if it tends to get steamy during showers, as excess moisture can affect the soap's texture.

By following these storage tips, you can keep your cold process soap in excellent condition, maintaining its appearance, fragrance, and performance for an extended period. Properly stored, cold process soap can last for a year or more while retaining its quality.


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