white powder when curing

[apleibo]

so, i am sure this has had to have been addressed previously, but i can't find it!

when curing my CP soaps, they get this white powdery look on the side that is exposed to the air. a few times this happened on the "back" side of the soap, but oddly enough, i even had this happen after i unmolded the soap, and it happened on the decorative side.

i once was told that when curing, you could just wipe this off with a rag, but that has not worked for me yet. any ideas to make this stop? the soap is overall great, but i feel like this takes away from its aesthetics.

thanks!
ali

 

[MsBien]

What you are talking about is most likely "soda ash" and it is a pain IMHO. Did you use distilled water? That does help elminate a lot of it. Also, some people have said that spraying the surface with rubbing alcohol helps but I've not tried that yet.

You might try searching "soda ash" to learn more.

Stacie

 

[Guest]

Ditto what msbien said and it helps to cover your soap mold with saran or something while it is gelling.

Kitn

 

[NatureandNurture]

'Soda ash' does that mean the white powder is actually NaOH that didn't react and has settled out of the solution? Is that powder caustic? I noticed OP mentioned that it was not on the air exposed side this time, but on the decorative side... I'm guessing she means the cut side of the bar. How did that happen if it was after the insulation period? Is that a common problem?

 

[Artephius]

'Soda ash' does that mean the white powder is actually NaOH that didn't react and has settled out of the solution? Is that powder caustic?

No worries, soda ash isn't caustic. From what I understand of the chemistry, soda ash is a salt (sodium carbonate) that's most commonly used as a water softener. The sodium ion is contributed by the lye, but it does not have the same properties of lye (as in, burning).

It usually only forms on parts of soap that are exposed to air (the top/cut sides) It doesn't hurt the soap, but some people don't like the look of it, hence decorative concerns.

So far I've only had visible soda ash when I used individual molds that I stuck in the fridge to prevent gel. That's probably because I usually wrap something over larger molds during the gel stage.