Types of Soap
When shopping for handmade soap, you may see terms like cold process, hot process, or melt & pour. These refer to different methods of soapmaking. Each has its own characteristics, but all can produce effective, skin-cleansing bars.
What Is Cold Process Soap?
Cold process soap is made by combining oils or fats with sodium hydroxide (lye). This chemical reaction, called saponification, transforms oils into soap.
The mixture is poured into molds and allowed to cure for several weeks. During curing:
The soap hardens.
Excess water evaporates.
The bar becomes milder and longer lasting.
Cold process soap allows for artistic designs and custom formulations. Because it cures slowly, it requires advance planning for bulk or custom orders.
This is my preferred method and comprises the majority of my soap production.
Typical cure time: 4–8 weeks
What Is Hot Process Soap?
Hot process soap uses the same ingredients as cold process soap, but heat is applied during production to speed up saponification.
This allows the soap to be used sooner than cold process soap. However, hot process bars often have a more rustic texture and less intricate design capability.
I rarely use this method. If I want a rustic bar I’m more likely to use techniques like intentional ricing with my cold process bars.
Typical cure time: 1–3 weeks
What Is Glycerin Soap?
Glycerin soap begins with a pre-made soap base. The base is melted, customized with fragrance or color, and poured into molds. Most melt & pour soap bases are pre-saponified soap that has already completed the chemical reaction. Some specialty bases may use synthetic surfactants, making them detergent bars rather than soap by definition.
Because the saponification process has already occurred, melt & pour soap does not require curing time. It can be packaged once hardened. It must be packaged to avoid “sweating”.
This method is often used for detailed shapes, custom favors, and specialty designs.
Typical cure time: N/A, can and should be packaged the same day as poured.
