When you make cold process soap, there’s a magical transformation that happens during the curing process, one of which is the gel phase. This phase is responsible for many of the beautiful characteristics of soap — including its texture, color, and firmness. However, if you’re new to soap making, the concept of gel phase can seem a bit mysterious. Should you encourage it? Or avoid it entirely?
In this article, we’ll break down exactly what gel phase is, why it happens, and how to control it for your cold process soap. By understanding gel phase and how to manage it, you’ll be able to create soaps with consistent quality, color, and texture every time.
What Is Gel Phase in Cold Process Soap?
The gel phase in cold process soap occurs when the soap’s internal temperature rises during the saponification process. Essentially, the chemical reaction that turns oils and lye into soap generates heat, and if the soap is insulated or kept warm, the temperature inside the mold can increase significantly. This heat causes the soap to gel in the center, giving it a smoother, more translucent texture.
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Temperature: Gel phase typically happens when the soap reaches a temperature between 130°F and 160°F (54°C to 71°C). The higher the temperature, the faster and more intense the gel phase will be.
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Visual Changes: You’ll notice the soap starts to become more translucent and shiny in the center. The edges may stay opaque while the center gels completely, creating a contrast that is visible when you cut the soap.
Why Does Gel Phase Happen?
Gel phase is a natural result of the exothermic reaction that occurs when lye and oils combine. As the soap reacts, it generates heat — and if the soap is insulated or kept warm, this heat accelerates the chemical process. The result is that the soap will go through a gel phase, which affects its texture, color, and overall quality.
But not all soap makers want to encourage gel phase, and that’s perfectly okay! The gel phase isn’t always necessary for a successful batch of soap. In fact, some people prefer the look and texture of soap that hasn’t gone through gel phase, as it can create a firmer bar with a more opaque appearance.
What Are the Benefits of Gel Phase?
While some soap makers choose to skip the gel phase, there are several benefits to allowing it to happen naturally in your soap:
1. Smoother Texture
When soap goes through gel phase, it often results in a smoother texture. The soap becomes softer, making it easier to cut into uniform bars. This is particularly noticeable when you use oils like olive oil or coconut oil, which can create a softer soap that benefits from the gel phase.
2. Improved Color
Gel phase can significantly affect the color of your soap. For certain fragrances, especially those that contain natural colorants or oils like vanilla, gel phase can help produce a richer, more vibrant color. For example, soaps that gel might turn out a more vivid shade of yellow, orange, or brown.
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Vanilla Fragrance: Fragrances like vanilla tend to darken in color during gel phase, creating a deep, warm hue.
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Clay or Natural Colorants: Some natural colorants, such as spirulina or turmeric, can produce deeper and more saturated colors when the soap goes through gel phase.
3. Faster Curing Time
Soap that has gone through gel phase tends to harden more quickly and reach the curing stage faster. This is because the soap reaches its saponification endpoint more quickly due to the increased heat.
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Note: This doesn’t mean the soap is completely ready to use right away, but it can speed up the curing process, especially if the soap is made with hard oils like palm or cocoa butter.
What Are the Downsides of Gel Phase?
While gel phase can enhance certain characteristics of your soap, it’s not always the desired result. There are a few potential downsides to consider:
1. Cracking or Warping
If the soap heats up too quickly during gel phase, it can cause the soap to crack or warp, especially in large batches. This is particularly common when highly insulating molds are used or if the soap mixture has too much water.
2. Unpredictable Results with Certain Additives
Certain ingredients, like micas, oxides, and some essential oils, can react differently when exposed to the high temperatures of gel phase. This can result in discoloration, swirling effects, or other unintended outcomes.
3. Unwanted Color Changes
While gel phase can enhance colors, it can also cause colors to darken too much or become muddy, particularly when using fragrance oils that contain vanilla or other darkening agents. This can be frustrating if you’re aiming for a specific color scheme.
How to Control the Gel Phase in Cold Process Soap
You may want to encourage or avoid the gel phase depending on your soap recipe, design, or personal preferences. Here’s how you can control it:
1. Encourage Gel Phase
If you want to encourage the gel phase to get that smooth, vibrant effect, try the following techniques:
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Insulate the Mold: After pouring your soap into the mold, cover it with a blanket, towel, or plastic wrap. This keeps the heat in and helps the soap reach the desired temperature for gel phase.
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Use a Warm Place: Place your soap in a warm area (like near a heating pad or in an oven with the light on) to encourage heat buildup.
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Use More Water: Soaps with a higher water content tend to gel more easily. This is particularly effective in batches that contain a high amount of olive oil or other soft oils.
2. Prevent Gel Phase
If you prefer to avoid gel phase and want your soap to stay opaque and firmer, follow these methods:
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Place Soap in the Fridge or Freezer: After pouring the soap into the mold, place it in the fridge or freezer to cool it down rapidly. This helps prevent the soap from reaching the temperatures necessary for gel phase to occur.
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Use Less Water: By reducing the amount of water in your recipe (such as going with a water discount), you reduce the chances of the soap getting too hot.
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Avoid Insulating: Do not cover or insulate the mold. Leave it uncovered to allow the soap to cool and solidify more slowly.
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Use Hard Oils: Hard oils, such as coconut oil or shea butter, naturally prevent excessive heating and reduce the chances of the soap entering gel phase.
Conclusion
Gel phase is a fascinating part of the cold process soap-making journey, and by understanding it, you can take full control over your soap’s texture, color, and curing process. Whether you choose to encourage it or prevent it, knowing how to manage gel phase will ensure you create the perfect soap every time.
Experiment with different techniques and find out what works best for your recipes. Over time, you’ll learn how to harness the gel phase to enhance the aesthetic and functional qualities of your handmade soap.