How and when cut your soap?
A few days to one week after you’ve made your soap you can unmould it and prepare it for the curing process. If you made salt soap better cut it one day after you made it as it can become very hard very fast.
During the 4 to 6 weeks of curing the saponification will finish and the soap will become milder. The pH of the soap will slightly decrease. And it will become harder because it will lose water.
What is a zap test?
First put on your gloves, as the lye might still be active, and unmould your soap.
You can check the pH of your soap with a pH meter or pH strips, however the strips are not always reliable.
In the soap makers’ world you will hear of the zap test. The zap test is when you touch the soap with the tip of your tongue and if you get a light zap like from a 9 volt battery then there is still unsaponified lye in your soap. If your soap has gelled, then it shouldn’t zap after 24 hours. If it hasn’t gelled it might zap up to 3 days.
If your soap zaps after 4 days then it might have too much lye in it (lye heavy) due to an incorrect formula or incorrect weighing of ingredients, so it might be unusable. If you have the formula and can recalculate the quantities, you can add the missing ingredients and re-batch it.
If the soap doesn’t zap you can slice it in individual bars and let them to cure. To cut the soap you can use a knife, a soap cutter (straight as in the picture above or crinkled) or a wire cutter (soap or cheese cutter).
How and where to cure your soap?
- In a place out of reach of children and pets;
- Not in direct sunlight as it will affect the quality of your soap. The essential oil and colours might fade;
- Align the bars next to each other but not touching, so they don’t get stuck to each other and have enough space;
- Not in extreme temperatures (too hot or cold), ideally around 24 degrees Celsius/77 Fahrenheit;
- In a dry place, not too humid, so it can lose water;
- Turn the bars every few days so they can lose moisture from all sides and won’t warp.
After the soap is cured keep them in paper bags or cardboard boxes so it can breathe. If you keep them in sealed plastic boxes it might grow mould!