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Cheryl writes, "I was wondering how long these bars have to sit before we can use them. I realize they have to be cut right away, and know the cure times for the lye , but things must change for the drying time...."
In this particular question, Cheryl was asking about the cure time for salt soap bars. Salt soap gets hard in just a couple of hours and needs to be cut right away. But Cheryl is right to ask about the cure time. However, the answer really applies to all soap, not just salt soap bars. Most soap making books or tutorials will say to allow your soap to cure for several weeks before you use it. And for the most part, they're right. But not really for the reason you'd expect.
Cure has two purposes:
- To allow the saponification process time to complete
- To allow the water in the soap to evaporate out
That's pretty much it. The saponification process is complete in about 24-48 hours. Which means your soap, including your salt soap bars, are safe and just fine to use after a day or two. HOWEVER, just because the soap is safe to use, doesn't mean that it's reached its peak yet. Soap really does benefit from a cure of a few weeks. The water evaporates out and the soap just seems to get a bit better. It seems a bit milder, lathers better and lasts longer in the shower. After a month or so, you're not going to see too much more added quality - but letting your soap cure for those extra few weeks really does make a difference.
So what do I do with my soap? I'll confess. I usually take a bar out of the batch after a day or two and use it - just to test out how much I like the fragrance. Then I let the rest of the batch cure for a month or so before putting it into the "good to use" soap drawer.
Mailbag Monday is a feature on the site where I share readers' questions and the answers. You can ask questions about candle making, soap making, or any of the related crafts that we engage in. Just email me with "Mailbag Monday" in the subject line. You can also check out previous questions I've answered in the Mailbag Monday Archive.