White layer formed on soap bar

[DrewsSoaps]

Hey, I’m newer to Bar soap making, very used to liquid soap, and I have a question about a new recipe I used, well, the results of the new recipe. So the question is about a white outer layer being formed on the soap bar, however the only parts of the soap that has the white layer are parts that were in direct contact with the circular silicone mold that I used. I’ve made more than 5 batches of soap with these molds, and each time I never had a white layer formed anywhere on the soap bar. when I washed the soap molds prior to pouring, I boiled them in a 1% alconox powdered detergent solution with a little dawn. I mean, yeah the soap molds felt ever so slightly slick after I washed them off, but I attributed it to them just being wet. This was an experimental batch as well, so I let a few GMP down. I’m just wondering if this is something anyone is familiar with, or if it could be most likely attributed to the silicone molds not being properly cleaned. I know that’s a hard Q to ask because you didn’t see the molds, but they were clean enough for me to use, so they weren’t dirty by any means. I am going to scrape some of the white outer layer off into a beaker with water and test the pH to see if it’s something alkaline, I’ll

Also make a control to test with the outer soap layer that didn’t have contact with the silicone tomorrow and I’ll post the results. I’m just trying to do this quickly because I wanna get a bigger HP soap batch ready to be able to send the people affected by the hurricane in NC. Thanks, pics and recipe

Attached

 

[bookworm42]

My guess is that it's soap ash. Was the white stuff there when you unmolded or did it form after?

Soap ash is purely cosmetic and should come off with a little water or steam. It's caused by lye reacting to water in the air.
Soap ash can be tricky. You can make 2 batches not change anything but one gets ash and the other doesn't.

 

[AliOop]

Yup, looks like soda ash to me, as well.

 

[KiwiMoose]

Are you sure it's on the sides that contacted the silicone? It looks like it's just on one side to me - usually the side that is exposed to the air ( i.e. not touching the silicone).

Any way - it's almost certainly soda ash and sometimes it just happens. It could be that you didn't gel the soap - but I sometimes still get it on gelled soap. Some recipes might be more prone to soda ash than others.

If you ascertain that it is indeed the side exposed to the air, then easiest way to stop it from happening is to cover the soap as soon as it's poured. If using individual/cavity molds such as this, I usually just tear off a sheet of baking paper and sit it on top of the mold (it needs to touch/stick to the top of the soap), then place a chopping board or similar on top of that. Leave them in the molds a little longer than necessary (maybe three or four days) to maximise their time without air exposure.

 

[Ekuzo]

I agree with the posts above, looks like soda ash to me as well. KiwiMoose gave a very detailed reply, you can't go wrong with that.

I've also heard you can soap hotter and pour at a thicker trace, as well as discount your liquid amount to minimize this effect

 

[DrewsSoaps]

My guess is that it's soap ash. Was the white stuff there when you unmolded or did it form after?

Soap ash is purely cosmetic and should come off with a little water or steam. It's caused by lye reacting to water in the air.
Soap ash can be tricky. You can make 2 batches not change anything but one gets ash and the other doesn't.The white laye

My guess is that it's soap ash. Was the white stuff there when you unmolded or did it form after?

Soap ash is purely cosmetic and should come off with a little water or steam. It's caused by lye reacting to water in the air.
Soap ash can be tricky. You can make 2 batches not change anything but one gets ash and the other doesn't.

Thank you for your reply. The white layer was on the soap as i was unmolding. So something had to happening during the 48 hr I let the soap sit in the molds. I’ll post my new finding in an edited section on the main thread.i have some Interesting findings.

Are you sure it's on the sides that contacted the silicone? It looks like it's just on one side to me - usually the side that is exposed to the air ( i.e. not touching the silicone).

Any way - it's almost certainly soda ash and sometimes it just happens. It could be that you didn't gel the soap - but I sometimes still get it on gelled soap. Some recipes might be more prone to soda ash than others.

If you ascertain that it is indeed the side exposed to the air, then easiest way to stop it from happening is to cover the soap as soon as it's poured. If using individual/cavity molds such as this, I usually just tear off a sheet of baking paper and sit it on top of the mold (it needs to touch/stick to the top of the soap), then place a chopping board or similar on top of that. Leave them in the molds a little longer than necessary (maybe three or four days) to maximise their time without air exposure.

Hey! Thank you so much for your help! The strange part is the top of the soap, that was exposed to air in the molds without any covering for about 72 hours, is the side that no white layer formed on. The side walls of the circular bar didn’t have as much of a white layer as the bottom of the bar soap. Which is weird because that means the parts that were unexposed for air are the parts that the white ash layer formed on.
I did some testing with my pH meter and here are the findings.
Beaker 1 = 1g of the bar soap sample that had no ash (top of bar) in 99g DI water.
Beaker 2 = 1g of the bar soap sample that did have ash (bottom of bar) in 99g DI water
Beaker 3 = 1 gram of a soap sample from a previous batch made 1 month ago with no ash layer, in 99 g DI water.
I should also say I’ve never had an issue with ash forming on my bars, however this recipe is new for me, I’m all sciencey and I was over complicating my recipes with things like stearic acid, beeswax, lauric acid, multiple salts, sugars and sugar alcohols, and it actually turned out amazing, but it hit false trace each time and made pouring into molds a pain. All of that to say, the recipe attached in the thread is my newest recipe that I formulated with help from this website, so part of me feels as if my recipe could be the culprit, but I don’t have any quantitative data to back that up with.
As for the results:
Beaker 1 pH = 10.15
Beaker 2 pH = 10.13
Beaker 3 pH =10.09
My theory is if the white layer were soda ash, beaker 2’s pH would be different than beaker 1.
So I am even more confused now.
I have also made dozens of liquid soap batches, and I always find neutralization puts the liquid soap at around 9.23pH. So I guess most liquid soaps are less basic than bar soaps. That’s a new finding for me, well, specifically for this recipe. Can’t say that for every bar soap / liquid soaps. I digress lol
But I understand if this is too much for anyone to help me figure out. I might just attribute it to user error in cleaning the molds. I’ll try the recipe again with the same parameters and see what happens.
Thanks!

Hey! Thank you so much for your help! The strange part is the top of the soap, that was exposed to air in the molds without any covering for about 72 hours, is the side that no white layer formed on. The side walls of the circular bar didn’t have as much of a white layer as the bottom of the bar soap. Which is weird because that means the parts that were unexposed for air are the parts that the white ash layer formed on.
I did some testing with my pH meter and here are the findings.
Beaker 1 = 1g of the bar soap sample that had no ash (top of bar) in 99g DI wa
Beaker 2 = 1g of the bar soap sample that did have ash (bottom of bar) in 99g DI water
Beaker 3 = 1 gram of a soap sample from a previous batch made 1 month ago with no ash layer, in 99 g DI water.
I should also say I’ve never had an issue with ash forming on my bars, however this recipe is new for me, I’m all sciencey and I was over complicating my recipes with things like stearic acid, beeswax, lauric acid, multiple salts, sugars and sugar alcohols, and it actually turned out amazing, but it hit false trace each time and made pouring into molds a pain. All of that to say, the recipe attached in the thread is my newest recipe that I formulated with help from this website, so part of me feels as if my recipe could be the culprit, but I don’t have any quantitative data to back that up with.
As for the results:
Beaker 1 pH = 10.15
Beaker 2 pH = 10.13
Beaker 3 pH =10.09
My theory is if the white layer were soda ash, beaker 2’s pH would be different than beaker 1.
So I am even more confused now.

I have also made dozens of liquid soap batches, and I always find neutralization puts the liquid soap at around 9.23pH. So I guess most liquid soaps are less basic than bar soaps. That’s a new finding for me, well, specifically for this recipe. Can’t say that for every bar soap / liquid soaps. I digress lol
But I understand if this is too much for anyone to help me figure out. I might just attribute it to user error in cleaning the molds. I’ll try the recipe again with the same parameters and see what happens.
Thanks!

@bookworm42 here are the results from the test

 

[bookworm42]

I have no idea.
Maybe when you boiled it there was residual dawn or alconox in your mold that reacted with your soap. Do you do that after every batch?

 

[DrewsSoaps]

I have no idea.
Maybe when you boiled it there was residual dawn or alconox in your mold that reacted with your soap. Do you do that after every batch?

I do, alconox digest the unsaponified oils and fats, so it usually gets them squeeky clean. The I do an additional tap water rinse and let the molds dry.

No worries, thanks for the help

 

[AliOop]

Some of my molds cause ash on the sides of my soaps, every single time. My best guesses are: either some ingredient mixed with the silicone causes this, or some residue of something I made got into the silicone.

Because I soap at cool temperatures, I also do have to fight ash on the exposed surfaces. To combat that, I use a combination of high lye concentration, gelling on a heating pad, covering after pouring, and re-covering after I have unmolded and cut the bars. The last thing was what finally conquered it for me. I need to cut my soap before it gets too hard to cut, but it still benefits from remaining covered for a few more days after the cut. HTH.

 

[ackosel]

Some of my molds cause ash on the sides of my soaps, every single time. My best guesses are: either some ingredient mixed with the silicone causes this, or some residue of something I made got into the silicone.

Because I soap at cool temperatures, I also do have to fight ash on the exposed surfaces. To combat that, I use a combination of high lye concentration, gelling on a heating pad, covering after pouring, and re-covering after I have unmolded and cut the bars. The last thing was what finally conquered it for me. I need to cut my soap before it gets too hard to cut, but it still benefits from remaining covered for a few more days after the cut. HTH.

Please pardon my intrusion, but how do you cover the cut bars? I have soda ash on every batch. Low temps (goat milk), I do cover and gel on a heating pad, but the bars always develop ash in the few days after cutting. Should I wrap each bar in plastic wrap for a few days (how many days?) Or can I put them all back together in loaf form and wrap them all together?

 

[AliOop]

Please pardon my intrusion, but how do you cover the cut bars? I have soda ash on every batch. Low temps (goat milk), I do cover and gel on a heating pad, but the bars always develop ash in the few days after cutting. Should I wrap each bar in plastic wrap for a few days (how many days?) Or can I put them all back together in loaf form and wrap them all together?

I move them close together, but loosely, not really touching. Then I put a single layer of cling wrap over the top and sides and kind of tuck it around, not super tightly but enough to keep out the majority of air. Doing this for a few days after cutting has almost eliminated ash entirely for me. Such a relief!

 

[ackosel]

I move them close together, but loosely, not really touching. Then I put a single layer of cling wrap over the top and sides and kind of tuck it around, not super tightly but enough to keep out the majority of air. Doing this for a few days after cutting has almost eliminated ash entirely for me. Such a relief!

Thank you so much! I have two, 4" loaves to unmold and cut tomorrow. I'll certainly try covering them as you suggest. THANK YOU!

 

[AliOop]

Thank you so much! I have two, 4" loaves to unmold and cut tomorrow. I'll certainly try covering them as you suggest. THANK YOU!

Wishing you an ash-free experience!