thin layer on top of soaps - soda ash?

[JLem]

I'm only three batches into making soap...but I have noticed on my last two there is this thin light-colored layer across the top of the soap (the side exposed to the air when in the mold). This photo below shows pretty clearly what I mean. The layer is solid, covering the entire top area. Is this soda ash? Seems like a lot. Or is it something else? Does this indicate an issue with either my recipes and/or process?

Here are my recipes:

Left:
200 grams Palm oil
200 grams Coconut oil
170 grams Olive oil
75 grams Sunflower oil
30 grams Sweet almond oil
257 grams distilled water
95 grams lye
~10ml each of lemon and cedar EOs added at trace

Right:
248 grams Olive oil
155 grams Palm oil
124 grams Coconut oil
62 grams Sunflower oil
31 grams Sweet almond oil
236 grams Peach Rooibos tea (brewed with distilled water and chilled overnight)
86 grams lye
powdered rooibos tea added at trace

 

[DeeAnna]

"... Is this soda ash? Seems like a lot...."

Yes, it probably is soda ash. And, yes, the left hand bar has quite a bit, but I've seen worse.

If you taste it, soda ash has an odd salty, bitter flavor, sometimes with a metallic tang. Just do a tiny taste to verify -- lightly dampen your fingertip, dab it on the ash, and lightly touch your finger to your tongue. If it's ash, it will not "zap" like a lye-heavy soap -- it should just have that distinctive taste. Not my favorite flavor, but not horrible.

You can remove it if you don't like the looks, but it's not dangerous, just unsightly. Ash is water soluble. Some people remove light coating of ash by steaming it away over a pan of simmering water or with a steam iron. There's enough on the left hand bar that steaming might not work well, however. Instead, I would either plane it off or wash it off with warm water and a bit of a gentle rub.

I didn't check your second recipe, but the first looks fine. Ash is a product of environmental conditions as much as anything. I don't have any suggestions for changes you could make to stop it.

 

[AnnaMarie]

Soap Queen recommends to spray the top of the soap with 91% isopropyl alcohol. I do this regularly and it works very well.

Cheers!
Anna Marie

 

[JLem]

Good to know. Thanks. Sounds like it's just a normal part of the process and nothing to worry about.

 

[DeeAnna]

Pretty much, yes.

As AnnaMarie pointed out, spraying the top of the soap in the mold with alcohol can help prevent ash, although I've seen people complain they still get ash anyway. I think they might be using a lower % alcohol -- you really do need high-proof alcohol for this to work the best.

When you get ash down the sides of a cut bar during cure, I'm not sure spraying alcohol will help. But it might be worth a try -- it certainly won't hurt anything.