How to Make Cold Process Soap: A Step-by-Step Guide for Beautiful Handmade Bars

 

Question

Help me with my soap making project. I made a bar soap but the results were not something to write home about. I used 2000 ml palm oil, 300ml lye (Sodium hydroxide) and 800 ml of water. I heated to the oil to a low temperature just to dilute it. Then I mixed the lye with water till it disolved, before I poured the Oil into the water. I stired with a stick because my electric hand mixer got spoiled the last time I used it. The soap gelled in seconds as I stired so that as I was putting it in the mold, I was literally scooping it. Ideally I should be able to pour out a thick liquid. Now the soap is crystalline hard, and it disintegrates when cutting instead of getting neat cuboids. The Questions are: Which ingredients were too much or too little? How can I achieve a soap that is easy to pour in the mold? How do I achieve a soap that does not become rock hard when it sets? Finally, my soap is an orange colour due to the palm oil. What is the most cost effective method for bleaching and at what point in the soap making is this done.

 

Answer to the Question on Soap Making

Making your own soap can be a rewarding process, transforming simple ingredients through a fascinating chemical reaction into a product we use every day. While your first attempt might not have gone as planned, understanding the key elements and techniques will set you on the path to creating beautiful and effective soap. Let's delve into the essentials.

The Fundamental Ingredients of the cold process soap making

At its core, soap making involves the interaction of fats or oils with an alkali solution. Understanding each component is crucial for success.

1. Lye (Sodium Hydroxide - NaOH): The Catalyst for Change

Lye is an essential ingredient in soap making; you cannot make true soap without it. It's a strong alkali that reacts with fats and oils in a process called saponification. However, it is crucial to handle lye with extreme caution. It is corrosive and can cause serious burns. Always wear gloves, eye protection, and long sleeves when working with lye. Ensure you have good ventilation to avoid inhaling any fumes when mixing it with water.

In your previous attempt, the amount of lye used appears to have been slightly high, contributing to the hard and brittle texture of your soap. It's vital to understand that lye measurements must be precise and based on weight (grams), not volume (milliliters).

The saponification value of an oil dictates how much lye is needed to react with a specific amount of that oil. For palm oil, the saponification value is approximately 0.144. This means that for every gram of palm oil, you need about 0.144 grams of pure sodium hydroxide for complete saponification. Using your approximate weight for 2000 ml of palm oil (around 1.8 kg or 1800 grams), you would need closer to 1800×0.144=259.2 grams of lye. Your use of 300 ml likely translated to a higher weight of lye than required.

Key Takeaway: Always use a reliable online soap recipe calculator. Input the weight of your oils (in grams), and it will provide the exact amount of lye needed.

2. Oils: The Foundation of Soap's Properties

The type and combination of oils you use will determine the final characteristics of your soap, such as its hardness, lather, and moisturizing ability. While any edible oil can technically be saponified, certain oils are preferred for their desirable qualities in soap making.

You used only palm oil, which is known for producing a hard bar of soap. Using a single oil often results in a less balanced soap. To achieve a soap that is both firm enough to cut cleanly and gentle on the skin, a blend of oils is recommended. Consider the following general guidelines for your recipes (always use a soap calculator for precise amounts based on the weight of your chosen oils):

• Olive Oil (e.g., 40-50%): Contributes to a mild, moisturizing bar with a gentle lather.
• Coconut Oil (e.g., 20-30%): Provides excellent lather and hardness. Use in moderation, as high percentages can be drying for some skin types.
• Palm Oil (e.g., 20-30%): Adds hardness to the soap.
• Shea Butter or Cocoa Butter (e.g., 5-10%): Introduce extra moisturizing properties and some firmness.
• Other Liquid Oils (e.g., sunflower, canola, soybean - use sparingly): Can contribute to a softer bar.

Key Takeaway: Experiment with different oil blends to discover the properties you desire in your soap. A balanced recipe is key to a high-quality bar.

3. Water: The Solvent for the Reaction in cold Process Soap Making

Water plays a crucial role as it dissolves the lye, creating the alkaline solution necessary for saponification. The ratio of water to lye is important. A common starting point is a water-to-lye ratio of 2:1 to 2.5:1 by weight.

The amount of water you used (800 ml) was likely adequate for the amount of oil. However, slightly increasing the water content (to around 850-900 ml for your initial oil quantity) can slow down the thickening process (trace), giving you more time to pour the soap into the mold. While more water initially results in a softer bar, the excess water evaporates during the curing process, and the soap will harden over time.

Key Takeaway: While a standard range exists, you can adjust the water-to-lye ratio slightly to influence the speed of trace. Always rely on your soap calculator for precise water amounts based on your oil and lye weights.

4. Fragrance and Color (Optional Enhancements in Soap Making)

Fragrance oils and colorants allow you to personalize your soap. Use fragrance oils specifically designed for soap making and add them at trace (when the mixture has thickened). For color, natural clays, micas, or soap-specific pigments can be used sparingly to achieve the desired aesthetic.

The Soap Making Technique: Step-by-Step

Turning these ingredients into soap requires careful execution and attention to safety.

Step 1: Prioritize Safety

Before you begin, ensure you are wearing appropriate safety gear: gloves, goggles, and long sleeves. Work in a well-ventilated area. Remember, lye is caustic and can cause burns.

Step 2: Prepare the Lye Solution

Measure your water (by weight) into a heat-resistant container. Slowly and carefully add the pre-weighed lye to the water, stirring gently until it is completely dissolved and the solution becomes clear. Never add water to lye, as this can cause a dangerous and potentially explosive reaction. The mixture will heat up significantly. Set it aside in a safe place to cool down. Good ventilation is crucial during this stage to avoid inhaling the fumes.

Step 3: Prepare the Oils

Weigh out your chosen oils according to your recipe. Gently melt any solid oils (like palm oil, coconut oil, shea butter, or cocoa butter) until they are liquid. Combine all the oils in a separate container and ensure they are at a similar temperature to your lye solution (typically between 32-49°C or 90-120°F).

Step 4: Combine Lye and Oils in Your Soap Making Process                                                                      

Once both the lye solution and the oils are at the recommended temperatures, slowly pour the lye solution into the oils while stirring continuously. You can use a stick blender for this step, which significantly speeds up the process and ensures thorough mixing. Continue blending until the mixture reaches "trace" – a point where it thickens enough to leave a faint trail on the surface when you drizzle some of it back into the pot (similar to thin custard).

The rapid gelling you experienced in your previous attempt was likely due to the high percentage of palm oil, a concentrated lye solution, and insufficient mixing with a stick blender. Working at slightly cooler temperatures for both the lye solution and the oils can also help slow down trace.

Step 5: Additives in Soap Making (Optional)

Once you reach trace, you can incorporate fragrance oils and colorants, if desired. Stir them in thoroughly.

Step 6: Pouring and Molding the Soap

Carefully pour the soap mixture into your chosen mold. Smooth the top if necessary.

Step 7: Curing the Soap

Cover the mold and leave it undisturbed for 24-48 hours to allow the soap to harden through a process called gel phase (which naturally occurs and helps produce a harder, more stable soap). After this initial period, unmold the soap and cut it into bars. Place the bars on a rack with good airflow to cure for 4-6 weeks. During this time, excess water evaporates, and the saponification process completes, resulting in a milder, longer-lasting bar of soap.

Addressing Specific Issues in Your Failed Soap Making Venture

• Hard and Brittle Soap: This was primarily due to an excess of lye and using only palm oil, which is a hard oil. Using precise lye measurements based on weight and incorporating softer oils like olive oil into your recipe will solve this.
• Soap Gelling Too Quickly to Pour: This rapid trace was likely caused by the high palm oil content, a possibly strong lye solution, and manual stirring. Using a stick blender for more efficient mixing and working with slightly cooler temperatures for your lye solution and oils can help. Increasing the water content slightly (within the recommended range of your soap calculator) can also slow down trace.
• Orange Color from Palm Oil: Palm oil naturally has an orange hue due to its beta-carotene content. You have several options to address this:
• Embrace the Natural Color: Work with the natural tone by adding other colorants to create warm shades or patterns.
• Use Refined Bleached Deodorized (RBD) Palm Oil: This type of palm oil has already undergone a bleaching process and will be significantly lighter in color. It might be slightly more expensive.
• Titanium Dioxide: This white pigment is very effective at whitening soap. Add a small amount (start with about 1 teaspoon per kilogram of oils and adjust as needed) to your oils before adding the lye solution. Mix it in thoroughly.
• Kaolin Clay: This natural clay can help to lighten the color of your soap. Add it at trace.
• Sun Bleaching (for raw oil): Exposing the raw palm oil to direct sunlight for several days can help to reduce its orange color before you use it in your soap recipe.

When to Add Bleaching Agents: Titanium dioxide and kaolin clay are typically added after trace but before pouring into the mold to ensure even distribution. Sun bleaching is done to the raw oil before you begin the soap-making process.

Final Thoughts About this Soap Making Process

Soap making is a blend of chemistry and artistry. By understanding the properties of your ingredients and following precise measurements and techniques, you can confidently create beautiful and functional soap. Don't be discouraged by initial setbacks; each batch is a learning experience. Embrace the process, take meticulous notes, and enjoy the journey of transforming simple elements into something truly useful. You now have the knowledge to approach your next batch with expertise and achieve the results you desire.

Caution: Soap making involves the use of sodium hydroxide (lye), a caustic substance that can cause serious injury if not handled properly. Always wear appropriate safety gear, including gloves, eye protection, and long sleeves, when working with lye. Ensure adequate ventilation and follow safe handling procedures. Keep lye and soap-making materials out of reach of children and pets. The information provided in this guide is for educational purposes only and should not be considered a substitute for professional advice. The user assumes all responsibility for any outcomes resulting from the use of this information.

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