One of the things I enjoy about soap making (and it is the same thing that can be so frustrating at the same time) is that no two batches are the same. You can use the exact same recipe and measure ever so carefully and the soap will be slightly different. There are a number of variables of course – the temperature of the room or oils and lye, humidity……
One of the things that can happen to soap is soda ash. This is a white powdery looking substance that appears on the top of you soap. There are a number of theories of why this happens. And a number of things that are suggested to stop it – cover your soap, spray it with alcohol several times during the first few hours, use beeswax in your recipe are a few. There are draw backs to each of these. So if you make more than a few batches of soap, you are bound to have soda ash at some point.
What is soda ash and does it matter? Soda ash is sodium carbonate that formed when sodium hydroxide (lye) in the soap contacted carbon dioxide in the air. It is completely harmless. In some cases it adds character and interest to the soap. Other times it is unacceptable.
This is an example where soda ash added interest to the top. This is Castile Soap that is slightly yellow from the olive oil and the ash is a nice white.
But soda ash definitely is unacceptable on this soap. It is just plain unappealing. So what to do? I wanted to save this soap and I didn’t want to plane the top of the soap so I searched for answers. There are several ways suggested besides planing the top:
1. Steam. I used my portable clothes steamer
2. Spray with alcohol
3. Rinse under cool running water.
4. Dip in vinegar water
Here are the results:
The best results were obtained by the rinsing the soap under running water followed by steaming it. Perhaps if the ash was not so thick the other methods would have worked better. This soap cleaned up nicely but not without a lot of effort. One important point – be sure you wear gloves when handling your soap avoid finger prints. Also have a rack to drain and dry the soap ready.
In conclusion, the most difficult method proved the most effective and the easiest way (spraying with alcohol) the least effective. No surprise there.