What is this odd color ring in my soap? (Pics)

[Sihir]

So this summer I've been having some "problems" with soda ash on my soaps, but it's been the rainiest and most humid spring and summer the state has seen in a long time, so I haven't been stressing about it too much. But on my most recent batch, I noticed a strange ring and a strange pattern developing. The top (on the left in below photo), like usual, developed a layer of soda ash.

Then the next section or two down that I cut, was the color I expected. (Middle slice.) But halfway down the log of soap, this definite ring pattern emerged (right-hand slice). It faded down at the other end of the tube as well.

Here's another shot of the second batch showing the same pattern in the same order. (Top most slice at top, second to third slice counterclockwise from top, then a middle slice.)

Any ideas?

 

[Obsidian]

Thats from partial gel. To stop it either make sure your batch fully gels by wrapping the mold in a towel to hold in heat or stop the gelling by putting the mold in the fridge or freezer.

 

[innerdiva73]

Partial Gel

 

[Sihir]

Thanks guys - very interesting. I always feel like I do things exactly the same every time so it was strange to have such a weird result this time around. Giving these away so I'm not worried about the cosmetic look, as long as that's all it is.

I get both my lye and oil to about 100 degrees before mixing - so then is the partial gel caused by it cooling too rapidly in the mold? It seems like there are a lot of variables. I can see why people keep notebooks for these things!

 

[Nite Hawk]

So this is what is considered a partial gel !
As a "newbie" didn't know what it meant. Had one very small batch do the same thing in the picture, but after it sat for a few weeks it turned all light colored, dried out and was normal looking and is using fine..
What happens if the whole bar of soap doesn't set up properly?
When it partial gels is it normal for it to age and turn normal colored?

 

[savonierre]

@ Nite Hawk, as a rule the partial stays the way it is..

 

[judymoody]

The line often becomes less distinct as the soap cures.

Gelling is pretty hard to avoid in a tube mold because there is less surface area to throw off heat than is the case with a loaf or tray mold. Certain fragrances also will heat up your soap batter, promoting gel, as will the use of milk, beer, or any liquid containining sugars.

Ungelled soap tends to get less ash than gelled soap.

It's only an aesthetic issue, call it a power circle or a bulls-eye and embrace the partial gel!

 

[Nite Hawk]

So the texture, hardness, and lather and everything is the same, no lye hotsposts,? just it looks a bit "funny"???
It sounds like it is caused by overheating, and not being able to cool down as it hardens, is that correct?
If so how would warming it in an oven correct the problem, unless it is being melted similar to a re-batch?
interesting thread...

 

[Bicycle808]

What happened here is, the center stayed hotter than the outer edges, and that's the part that gelled. Gelled soap has saponified faster, so technically it will become harder sooner than the outer edges, but once the bar is cured out, there won't be any discernible differences between the gelled inner and the ungelled outer rings. Aside from coloration, of course. (And yes, it gets less distinct as the soap cures, but it will remain noticeable.)

The OP, Sihir, mentioned that s/he always soaps the same way... but even changes in ambient temperatures, or seemingly subtle changes to the recipe, can change the temp in-mold and cause changes in whether the soap gels or not, and how thoroughly it will gel...

HTH,
Rob

 

[Sihir]

Gelling is pretty hard to avoid in a tube mold because there is less surface area to throw off heat than is the case with a loaf or tray mold. Certain fragrances also will heat up your soap batter, promoting gel, as will the use of milk, beer, or any liquid containining sugars.

Ungelled soap tends to get less ash than gelled soap.

It's only an aesthetic issue, call it a power circle or a bulls-eye and embrace the partial gel!

So that's why so many people use the loaf molds! I was wondering what specific advantage there was to them besides the ability to swirl/decorate the top of each bar.

I am definitely going to embrace the partial gel!

So the texture, hardness, and lather and everything is the same, no lye hotsposts,? just it looks a bit "funny"???
It sounds like it is caused by overheating, and not being able to cool down as it hardens, is that correct?
If so how would warming it in an oven correct the problem, unless it is being melted similar to a re-batch?
interesting thread...

From my (limited, and inexperienced) understanding, warming it in an oven (or wrapping towels around it) right after you pour it in the mold achieves the same purpose as putting it in the fridge/freezer - it ensures that all of the soap remains the same temperature so that it either gels (towels and oven) or doesn't (fridge.) The partial gel is from the outside ring being much cooler than the inside, so in either case the objective is to keep the entire mold the same temperature, whether warmer or cooler.

The OP, Sihir, mentioned that s/he always soaps the same way... but even changes in ambient temperatures, or seemingly subtle changes to the recipe, can change the temp in-mold and cause changes in whether the soap gels or not, and how thoroughly it will gel...

HTH,
Rob

Thanks, Rob! This must be it - I hadn't done a batch in about 2 months prior to this one, but in that interim the inside of our house has changed from the winter/spring standard of 68-70 to the summer standard of 74. This must have something to do with it! That and experimenting with new oils...(cedarwood and jasmine, mostly.)

 

[Marilyna]

You should be fine if you just wrap it with a towel to get a full gel.