Am I crazy?

[Kittish]

I think I'm noticing a trend regarding soap developing ash. The last two batches I've made I mixed to med-thick trace before pouring. Absolutely minimal ash on both of them. Other soaps that I've had accelerate or also got mixed to a thicker trace also didn't develop ash, or not much.

By comparison, soaps that I've poured at thin trace almost all have developed ash. The thinner the trace, the thicker the ash.

DeeAnna's most excellent explanation of the dynamic nature of soap has got me to thinking, might ash be the in part the result of those dynamics, where Na molecules and ions react with the air at the interface or that has gotten mixed in with the soap (such as by swirling)? Thinner soap batter would allow more circulation and more easily absorb air. This might also partially explain why people have such various results with methods intended to reduce or prevent ash.

I have already edited this post and added it to my "soapy stuff" articles: http://www.soapmakingforum.com/showpost.php?p=634104&postcount=51. I'd forgotten about the post I wrote explaining why soap is alkaline -- http://www.soapmakingforum.com/showpost.php?p=394531 -- I need to add that it to my articles too. I see at the time this thread was active that I was still in love with shampoo bars, but I've since changed my tune. I eventually cut off a bunch of my hair even though I was using an acid rinse. The rinse slows down the damage, but doesn't stop it. I think I also have another post where I talk about the saponification party -- I'll see if I can hunt it up on my hard drive.

***

As far as the idea that superfat added after a hot process (HP) cook will then remain unchanged in the soap forever 'n ever -- this idea is not entirely correct from the bits and pieces I've put together.

In the second link I gave above, I talk about a dynamic equilibrium:

"...The resulting bar of soap is not a boringly static, unchanging block of stuff.... The chemistry going on ... is constantly changing -- it's like a huge party where all kinds of microscopically tiny people are circulating around. Some people "hook up" with each other and some just cruise. Some may hook up, but later unhook, cruise for awhile, and hook up with someone different.

"In chemistry terms, all this partying and circulating is called a "dynamic equilibrium". Obviously, many soap particles are created when the fatty acids and the sodium ions "hook up" more or less permanently to form the chemically neutral molecules we call soap. But there are also the chemical loners who circulate in the watery liquid inside the soap structure -- these include some sodium ions (Na+), some fatty acid ions (Ste- [stearic acid] and others), and the H+ and OH- [hydrogen and hydroxide] ions released by the lye and the fatty acids...."

This dynamic equilibrium also affects the fats remaining in the soap. Remember that soaping fats have three fatty acids and a glycerin. An alkali such as NaOH can break off the fatty acids reasonably easily -- we call this chemical reaction "saponification" and the result is soap. It turns out something as simple as water can break a fat molecule apart too. The chemical reaction of fat with water is called "hydrolysis" (hi-draw-luh-sis). The ultimate result of hydrolysis is a mix of free fatty acids, glycerin, and partly deconstructed fat.

Hydrolysis under normal conditions is slower than saponification, but it still happens. If the fat happens to be the superfat in a bar of soap, that super-duper deluxe expensive miracle oil you originally added to the soap will not stay intact. It will be gradually changed by hydrolysis into simpler chemicals that aren't anything like the original fat.

How fast does this transformation happen? As with so many soapy things, the answer is "it depends." Saturated superfat and monounsaturated superfat are more likely to remain mostly intact for a longer time; polyunsaturated superfat probably won't last as long (many exotic miracle fats are polyunsaturated). Anything that slows down rancidity (DOS) will also slow down hydrolysis, so antioxidants and chelators (ROE, EDTA, citrate, etc) and cool, dry, dark storage conditions may all help.

The bottom line is superfat added to HP soap after the cook will remain more or less in its original form for awhile, but it will not remain intact forever.

I suppose the thing to do would be test my theory. Make two batches of soap to the same recipe, mix one to thin trace and pour, mix the other to thick trace and pour and see what happens.

 

[Cellador]

You know, that's funny. I hadn't thought of it before, but...the batches I've poured thin seem to have developed more ash too. Hmmm, I'll be interested in what the "experts" have to say...:think:

 

[Kamahido]

I pour mine at emulsion, spray with alcohol, and use Cold Process Oven Process. I seldom see much soda ash.

 

[Kittish]

I pour mine at emulsion, spray with alcohol, and use Cold Process Oven Process. I seldom see much soda ash.

So I'll need a third batch for the experiment I have in mind, mixed to emulsion, sprayed and CPOP'd. I guess if I'm going to do that, I should also do a batch that gets covered with plastic film.

 

[MorpheusPA]

I pour mine at emulsion, spray with alcohol, and use Cold Process Oven Process. I seldom see much soda ash.

This. Although depending on the swirl and the chunkiness I want, I can pour from anything from emulsion to medium trace.

Speeding the saponification with heat seems to suppress out soda ash, although some bars did get a bit of it.

Just spraying with alcohol every twenty minutes or so, three or four times on a batch that doesn't go in the oven, helps a ton.

Spraying with alcohol (I use 90% isopropyl) once or twice and CPOP-ing the thing is a combination that seems to beat 99% of soda ash.

 

[Saranac]

I think I'm noticing a trend regarding soap developing ash. The last two batches I've made I mixed to med-thick trace before pouring. Absolutely minimal ash on both of them. Other soaps that I've had accelerate or also got mixed to a thicker trace also didn't develop ash, or not much.

By comparison, soaps that I've poured at thin trace almost all have developed ash. The thinner the trace, the thicker the ash.

Most of the fragrance oils I use accelerate, which means that by the time I've poured, things are setting up real good. Those batches are CPOPed and I have NO issues with ash.

But one of my blends thins out my batter and it takes a good 30 minutes for it to set up enough in the mold to be moved. That scent, even though it's also CPOPed, ALWAYS has a thick layer of ash.

IMO, there might be merit to your hypothesis.

 

[SaltedFig]

Hi Kittish.

These photo's support your theory: http://www.soapmakingforum.com/showthread.php?t=67400

In the Andalusion Soap thread (making deliberately lye heavy, extreme high water, olive oil soap), it was noted in that thread that the excess water is necessary to carry the soda ash through to the middle of the bar (otherwise the soap will remain lye heavy in the middle).
http://www.soapmakingforum.com/showthread.php?t=42922&page=59

 

[mx5inpenn]

I have noted this to some extent. It took me a while to catch on because temperature seems to play a part also. I almost never get ash during the warmer months, but as soon as it gets cold out, it starts to appear. The thinner the batter, the heavier it is usually, but the ones I pour at emulsion during the summer don't get it. I spray with alcohol and cpop to combat it in the winter. Every now and then a stubborn one will still need steamed.

 

[psfred]

You are quite correct -- soda ash is sodium carbonate produced by the free lye in the soap reacting with carbon dioxide in the air and precipitating as the white, finely powdered salt.

The more free lye there is at the surface of the soap, the more "ash" you will get. If you pour at thick trace and oven process, you will get very little, and even less if you cover the surface with plastic wrap or spray with alcohol, both of which prevent CO2 from reaching the soap. Once you have gel phase, there isn't much free lye left to react, so you get much less ash.

The Andualusian "high lye" soap requires a lot of water to keep the soap permiable by CO2 long enough for all the lye to react and become sodium carbonate. Probably the only case in which one want's to have the soap cure as slowly as possible, eh?