The best tool to prevent crumbling and produce perfectly uniform bars, especially for softer or freshly made soap is a wire cutter. I cut my cold process soaps 36-48 hours after they have been poured into the mold. I use a wired multi-bar soap cutter. Fun fact: the wires are actual guitar strings! Then, the soap needs to cure (aka hang out on a shelf to air dry) for a minimum of six weeks - I prefer eight before I package it for sale.
During this curing time, a few important things happen:
✅Excess water evaporates, which makes the bar harder and longer-lasting (and can reduce the weight by up to 10%).
✅The process of saponification (turning oils and butters into soap by combining them with an alkali solution) finishes completely.
✅The soap becomes milder and more gentle on the skin.
✅Fatty acids form stable soap crystals, which also contribute to hardness and better performance.
Handmade soap is usually safe to handle when it’s first cut, but using it before it’s fully cured often leads to disappointment: soap that melts away quickly, produces little or no lather, and can even be irritating for some skin types. Good soap improves with time. (The Soap Cure)