indented lines in one part of soap + discoloration

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New Member
Feb 10, 2024
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Indiana, USA
Hello! I've been learning from and reading SMF for a couple years now but finally registered 🥂

I've been having some trouble making uncomplicated soap batches lately, so I thought I'd post here to see if anyone can help identify what's going on in the latest batch.

I used to live in a tropical climate and recently moved to the midwest (US) and have been having some issues with partial gel. Last night, I tried CPOP for the first time - I soaped with oils and lye between 109-114F (if I remember correctly!), stuck it in the oven at 175F for about 20min, then turned off the oven and left it there overnight. The soap was totally cool (when I touched the outside of the mold) in the morning - this is in contrast to other recent batches where I just insulate with two towels and leave it on the counter overnight - those batches are often still warm to the touch in the morning. Anyhow...I digress...

There are several issues with this soap - there's definitely partial gel in the center (which surprised me, because I was really thinking I would avoid it by CPOPing)...and my new TD didn't disperse well :( But the mysteries I'm hoping to get some input on...
- what caused the indented lines running horizontally in the green layer? Are these glycerin rivers? Or essential oils that maybe didn't get fully incorporated? I did, however, stick blend a bit after I put in the essential oil blend...maybe that wasn't a good idea but I thought that would help make sure they were properly incorporated. What this actually reminds me of is photos of "ghost swirls" I've seen...but that is a water I'm a bit stumped.
- why are there two different shades of green (as shown in second photo)? This only happened on the edges of the mold. I've often dealt with soda ash on the edges of soaps but this doesn't look the same. It almost looks like an intentional swirl.

Any ideas on what's going on here? Thanks so much for reading...I'm including recipe info below...

coconut oil 203g
lard 50g
shea 125g
olive pomace 300g
canola 175g
castor oil 63g

water 229g
NaOH 123.8g

lye concentration 35%
superfat 6%

essential oil blend: peppermint, listea cubeba, lemon 5x, bergamot
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The indented lines are probably from overheating. Most folks preheat the oven to 175F but turn it off immediately once they put the soap inside. By leaving the oven on, you were lucky to get only that mild tunneling, and not a full volcano.

You didn't mention what you used for the green color. Without knowing that, my best guess is that the color variations are either glycerin rivers or soda ash, or a combination of the two Glycerin rivers are always more likely with added heat, as well as TD. I also get glycerin rivers sometimes with French green clay, so if you used that for your green color, that could be a factor, as well.
Hi @AliOop, thanks for the reply! That's helpful. I used a combo of French green clay and a green mica.

An update: maybe 24hrs after being cut, the lighter green faded to be the same as the darker green color. That was interesting...then the bars also developed more soda ash, especially around the circle of the partial gel.

That brings me to another question...if the tunneling was due to overheating, why do you think the loaf didn't completely gel? Is it possible that the temp was too high at the start, and then dropped too quickly or something?

Thanks again for any ideas :)
It’s certainly possible. I do agree that it’s odd to have partial gel when the oven was so hot. To quote our resident soap philosopher, @KiwiMoose: “Soap do what soap do.” 🤷🏻‍♀️😉

I personally use a heating pad and an overturned box, rather than the oven. It allows me to keep a better eye on things (although I rarely check on it anymore - just set and go).