Glossary
Insulation
Wrapping or boxing a freshly poured soap mold to hold in heat and encourage a full gel phase.
Insulation, in soap making, means wrapping a freshly poured mold in towels or blankets, or placing it inside a closed box, to hold in the heat the batter generates as it saponifies. The goal is usually to encourage a full, even gel phase rather than a partial one.
How much insulation a batch needs depends on the recipe and the ambient room temperature. Recipes high in sugar-based additives like honey or milk already run hot and may need little or no extra insulation, while recipes made in a cold room or with a heavy water discount often need more help to gel evenly.
Over-insulating a batch that is already running hot is a common mistake and can push it past gel into overheating, causing cracks, a raised dome, or a volcano-like overflow through the center. If a batch looks like it is overheating, removing insulation or moving it somewhere cooler can help bring the temperature back down.