What Is Cold Process Soap? Everything You Need to Know
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If you've ever shopped for handmade soap, you've probably come across the term cold process soap. But what exactly does it mean, and why do so many artisan soap makers use this traditional method?
In this guide, we'll answer the question "what is cold process soap?", explain how handmade soap is made, and explore the many cold process soap benefits that have made it a favourite among skincare enthusiasts.
What Is Cold Process Soap?
Cold process soap is a type of handmade soap created by combining natural oils and butters with a carefully measured alkaline solution. This chemical reaction, known as saponification, transforms the oils into soap and naturally produces glycerin, a valuable ingredient that helps attract moisture to the skin.
Unlike some commercial manufacturing methods that rely on high temperatures or pre-made soap bases, cold process soap is made from scratch. Once poured into moulds, it is left to harden before curing for several weeks, allowing excess water to evaporate and the bar to become milder and longer-lasting.
The result is a luxurious, high-quality soap that cleanses effectively while retaining the natural properties of its carefully selected ingredients.
How Handmade Soap Is Made
Understanding how handmade soap is made helps explain why cold process soap is so highly regarded.
The process generally involves the following steps:
1. Selecting Premium Oils and Butters
Every soap recipe begins with a carefully balanced blend of oils and butters. Common ingredients include:
- Olive oil for gentle cleansing and conditioning
- Shea butter for a creamy, luxurious feel
- Coconut oil for a rich lather
- Castor oil to enhance bubbles and conditioning
Each ingredient contributes unique qualities to the finished bar.
2. Preparing the Lye Solution
Sodium hydroxide, commonly known as lye, is dissolved in water to create the alkaline solution required for saponification.
Although lye is essential during soap making, it is completely consumed during the chemical reaction when the recipe is correctly formulated and the soap has fully cured. Properly made cold process soap contains no residual lye.
3. Mixing the Ingredients
The oils and lye solution are combined and blended until the mixture reaches "trace," a stage where it begins to thicken.
At this point, fragrances, colourants and other additives can be incorporated before the soap is poured into moulds.
4. Moulding and Insulating
The soap mixture is poured into moulds and left to harden over the next 24 to 48 hours.
During this stage, saponification continues as the ingredients transform into soap.
5. Cutting and Curing
After unmoulding, the soap is cut into bars and left to cure for four to six weeks.
This curing period is one of the defining features of cold process soap. It allows excess water to evaporate, producing a harder, longer-lasting bar with a richer lather and a gentler feel on the skin.
Cold Process Soap Benefits
There are many reasons why artisan soap makers continue to use the cold process method.
Naturally Retains Glycerin
One of the biggest cold process soap benefits is that the naturally produced glycerin remains in the finished bar.
Glycerin is a humectant, meaning it helps attract moisture to the skin, leaving it feeling softer after washing.
Rich in Plant Oils and Butters
Cold process soap is typically made using nourishing ingredients such as olive oil, shea butter and coconut oil.
These ingredients contribute to a luxurious cleansing experience and help create a creamy, stable lather.
Gentle Cleansing
Because many cold process soaps rely on high-quality plant oils rather than harsh detergents, they are often favoured by people looking for a gentler everyday cleanser.
Individual skin types vary, but many users find handmade soap leaves their skin feeling comfortable rather than stripped.
Longer Lasting Bars
The extended curing process produces a harder soap bar that can last surprisingly well when stored correctly.
Allowing the soap to dry between uses on a draining soap dish helps maximise its lifespan.
Small-Batch Craftsmanship
Cold process soap is usually produced in small batches by artisan makers who carefully monitor every stage of production.
This attention to detail helps ensure consistent quality and allows for unique fragrances, colours and designs.
Cold Process Soap vs Melt and Pour Soap
People often confuse cold process soap with melt and pour soap, but they are very different.
Cold process soap is made entirely from raw oils, butters and lye, with the soap created through saponification.
Melt and pour soap starts with a pre-made soap base that has already undergone saponification. The base is simply melted, coloured, fragranced and poured into moulds.
Both methods produce usable soap, but cold process soap offers complete control over ingredient selection and formulation.
Does Cold Process Soap Contain Lye?
This is one of the most common questions asked by customers.
The answer is yes—during manufacture.
Lye is an essential ingredient because it reacts with the oils to create soap. However, once saponification is complete and the soap has fully cured, properly formulated cold process soap contains no free sodium hydroxide.
Without lye, soap simply cannot be made.
Why Does Cold Process Soap Need to Cure?
Freshly made soap contains excess water and has not yet reached its optimal hardness.
Allowing the bars to cure for several weeks improves:
- Hardness
- Longevity
- Lather quality
- Mildness
Although waiting several weeks requires patience, it is one reason cold process soap is considered a premium handmade product.
Is Cold Process Soap Better Than Commercial Soap?
Both have their place, but many people prefer cold process soap because it offers:
- Naturally retained glycerin
- Premium plant oils and butters
- Small-batch craftsmanship
- Beautiful fragrances
- Luxurious lather
- Greater control over ingredients
Commercial soaps are designed for large-scale manufacturing and consistency, whereas artisan cold process soaps often prioritise ingredient quality and the overall user experience.
Frequently Asked Questions
How long does cold process soap last?
A well-made bar typically lasts several weeks with normal use. Storing it on a draining soap dish and allowing it to dry between uses will significantly extend its life.
Can you use cold process soap every day?
Yes. Most cold process soaps are suitable for daily use, although everyone's skin is different. If irritation occurs, discontinue use and seek advice from a healthcare professional.
Is cold process soap natural?
Cold process soap is often made using natural oils and butters, but "natural" has no single legal definition in cosmetics. Always check the ingredient list to understand exactly what a product contains.
Why is handmade cold process soap more expensive?
Handmade soap requires premium ingredients, skilled craftsmanship and a curing period of several weeks. These factors increase production costs but also contribute to the quality of the finished bar.
Final Thoughts
If you've been wondering what is cold process soap, the answer is simple: it's a traditional method of making handmade soap from scratch using carefully selected oils, butters and lye. Through the process of saponification and several weeks of curing, these ingredients are transformed into a luxurious soap that retains naturally produced glycerin and delivers a rich, creamy lather.
The many cold process soap benefits—including premium ingredients, gentle cleansing, naturally retained glycerin and small-batch craftsmanship—are why this method remains the gold standard for artisan soap makers.
At The Velvet Lather Co., every bar is handcrafted using the cold process method and cured with care to ensure exceptional quality. Explore our collection of luxury handmade soaps and experience the difference that traditional craftsmanship can make.