What Is Gel Phase?
How it works, when to encourage it, and when to skip it
What Actually Happens
Saponification is exothermic (produces heat). As the reaction accelerates, the internal temperature climbs above roughly 140–160°F (60–71°C). The soap temporarily becomes semi-translucent, glossy, and wobbly—looking much like petroleum jelly.
This state lasts for 1–2 hours. As the soap cools, it hardens back to a solid. The resulting bar has more vibrant color, a denser texture, and a shinier cut surface than soap that didn't gel.
How to Encourage Gel Phase
Encouraging gel phase requires trapping the heat produced by the soap.
Standard Insulation
Cover the top of the mold with a piece of cardboard or a silicone mat, then wrap the entire mold in a thick towel. Leave undisturbed for 24 hours.CPOP (Cold Process Oven Process)
Preheat your oven to 170°F (77°C), turn it OFF, then place the freshly poured mold inside. Leave for 8–12 hours. This provides very even heat.Warmer Temperatures
Starting with oils and lye around 110–130°F (43–54°C) gives the reaction a head start, making gel more likely.How to Prevent Gel Phase
Some makers prefer the matte, opaque look of non-gelled soap, or need to prevent overheating in milk soaps.
- Refrigerate immediately: Place the mold in the fridge for 24–48 hours.
- Freeze milk soap: Place milk-based batches in the freezer for 24 hours.
- Soap cool: Work with oils and lye at 80–90°F (27–32°C).
- Don't insulate: Leave the mold uncovered in a room-temperature space.
Gelled vs. Non-Gelled
| Property | Gelled | Not Gelled |
|---|---|---|
| Cut surface | Shiny, glassy | Matte, chalky |
| Color | More vibrant | More muted/pastel |
| Texture | Denser, harder | Slightly softer initially |
| Unmold time | ~24 hours | 48–72 hours |
| Soda ash risk | Lower | Higher |
Frequently Asked Questions
Tip: Calculate your recipe in SoapMath
SoapMath calculates your exact lye and water amounts. Use it before you start so you can focus on the process.