A full proof way to create soda ash on cold process soap.
Why know HOW to create soda ash? If you know how it happens, then you'll see the steps required to avoid it.
What is soda ash? The quick explanation is, soda ash forms when unsaponified lye reacts with naturally occurring carbon dioxide in the air on the surface of cold process soap. Soda ash is harmless on fully cured soap and can occur inside cold process soap.
Why would you need a step-by-step way to create soda ash? If you don't know how to create it, breaking these steps down and applying them to your accidental soda ash, may help give you insight to your creation of soda ash, which is all soaper's nemesis.
I would not have thought to create soda ash as a lesson on soda ash, but that is exactly what I did. I taught myself how to create soda ash on cold process soap and it was successful!
Lately I have had soda ash on my entire cut bars of cold process soap. This has only happened once on an entire bar out of the hundreds of bars of soap, and it stumped me.
The first thing I wanted to focus on was the fragrance oil, since that seemed to be the only variable, however, upon closer examination I saw subtle alterations in the process.
I thought I knew how to successfully avoid soda ash - that light dusting of white substance (sodium carbonate) - that generally covers the top of soap, but can cover the entire bar.
After much investigation, asking for guidance in soap groups and doing a lot of reading I have the key steps to create soda ash.
- First of all, have a lot of water in the soap. What does that mean exactly? There is a water percentage that hits the sweet spot but is highly contingent on the humidity in the area. Too much water per oil/butters.
- Second, ensure that the soap is exposed to as much air as possible.
- Third, ensure there is humidity in the air.
- Fourth, interrupt the saponification process by un-molding and cutting the soap into bars, therefore creating more surface for air to come into contact with un-saponified soap.
- Fifth, understand that more water in the soap combined with humidity in the air lengthens the saponification process. Now, cutting the soap gives more area surface for air to interact with the lye/water evaporation causing a sure-fire dusting of calcium carbonate on every exposed surface.
How to avoid Soda Ash:
- Depending on humidity in your area, create cold process soap with a steep water discount. Less than 30% water is a good place to start. (I live in the desert so use a standard of 33% water with this soap calculator.)
- Spray the top of the fresh soap with 91% alcohol. This causes faster evaporation on the surface, temporarily.
- Cover the top of the soap to lessen the air contact. Use plastic wrap and seal the air away from the active soap.
- Allow 2-3 days to let the soap go through the full saponification process (generally less, but its a good rule of thumb.) Although soap can be un-molded that does not mean saponification has stopped.
- Pray the soda ash gremlins do not visit your house. Putting a sign on your front door that says, "Soap Witch Lives Here" has been known to keep those pesky soap gremlins at bay, however there are those who are persistent. (This requires more investigation and is on-going process. Check back for "Soap Gremlin Updates".)
Yes, soda ash can be washed or steamed off easy enough, however, if you have glitter or a complex high top this become a little daunting.
Now we have the perfect storm to create soda ash, if you so desire. A little known fact is that by consciously creating soda ash, the Soap Gremlin are highly confused.
Good luck with your next project if you choose to create soda ash, I hope you are as successful as I have been.
Please, if you know other techniques about creating or avoiding soda ash, leave your helpful comments here. Together we might be able to confuse those soda ash gremlins, if not defeat them. ;)
P.S. Heat helps water evaporate, so let's not forget that little bit of chemistry of applying heat to this already exothermic reaction of saponification.
P.S.S. You can do all there is to create soda ash and it won't happen, while other times we can do all those things to avoid it and it happens in spades. Fickle unscientific soap chemistry, indeed.