Troubleshooting 'icky' soap 10 months old

[KiwiMoose]

I made a soap last July, that by December had lost its scent. By January it had discoloured in the white portions to a caramel-brown colour and smelt a bit oily. Like cooking oil kinda smell. I've kept the remaining bars and today I noticed they were all 'sweaty' and oily on the surface. It smells like a wood oil, not a fragranced soap. Not pleasant but not rancid smelling.
Looking back at the recipe - I went through a phase of using 10% avocado oil, of which this batch of soap was one, so I checked all my soaps made with that recipe and don't recall having any problems with those, but I only have one of those other fragrances left of the 5 or so batches I made at that time. So I think I've satisfied myself that its not the additional avocado oil. Unless anyone can cite any issues they've had with 10% avocado oil?
The next option is the FO - which was Sugar Plum - think possibly from Nature's Garden but not 100% since my supplier here can be a bit vague about where it's from. I also added a bit of Sweet Orange EO - which I use in a lot of my soap with no problem.
All other ingredients in the soap were as per normal, so there was nothing untoward about them - my soaps usually last well over the 10 month mark without this kind of thing happening. I cut all the outside of one of the bars off, and the browny colour goes all the way though, but the soap still performs well. Just smells like I've washed my hands with cooking oil is all.

Anyway - have a look a see if any of you can come up with any reason why this might have happened?

 

[Obsidian]

That is definitely rancid. I've never had mine develop the really bad smell, usually just gets old and stale scented.

I don't think its the avocado, I've used it at way more then 10% with no issues.
It can be so hard to diagnose rancidity. I have problems with high olive oil, even had a Castile got dos after 3 weeks. Whole batch went bad.

Another member can't use a high amount of lard, regardless of brand, it will all get dos but I use 50% and rarely get spots.

Maybe that batch was contaminated with something, maybe a additive reacted badly. I wouldn't worry to much about it unless you start getting more throughout multiple batches.

Throw out the bad soap and clean the area. I had seen dos spread to surrounding soaps if too close together.

 

[shunt2011]

I agree with Obsidian. It’s definitely rancid. Will probably never know exactly why. I’ve had soap do that using the same recipe. I too use avocado without issue at 10-15%. I’ve only had it happen a couple times and it is frustrating for sure. My biggest issue has been plain 100% CO soap with 0 sf for stain sticks. I’ve quit making them

 

[penelopejane]

Did you use faux sea water? That went rancid on me and a few others I’ve talked to.

I had other batches go rancid and they all linked back to one new (well in date) 1 litre bottle of jojoba oil - used as low as 1%. So disappointing.

I’m meticulous about contamination from hands and equipment so I know the cause in these cases but there are lots of causes of DOS and it’s sometimes difficult to trace even if you keep great records.

 

[KiwiMoose]

I agree with Obsidian. It’s definitely rancid. Will probably never know exactly why. I’ve had soap do that using the same recipe. I too use avocado without issue at 10-15%. I’ve only had it happen a couple times and it is frustrating for sure. My biggest issue has been plain 100% CO soap with 0 sf for stain sticks. I’ve quit making them

Yes the main concern is if someone out there has that very soap sitting in their undies drawer not being used. Now their smalls will stink! I guess we can't really control that, other than using preservatives in my soap which I'd rather not do.

 

[Marsi]

This is might sound odd, but the shapes that your oily soaps made look very fungus.

July was also around the time you also started with your fresh Aloe ... perhaps it could be a bit of superfat, and a dash of Fun Guy?

Pic 3 - the circles with the dip in the middle (the top part of the soap pic would make very excellent dragon scales )

 

[KiwiMoose]

This is might sound odd, but the shapes that your oily soaps made look very fungus.

July was also around the time you also started with your fresh Aloe ... perhaps it could be a bit of superfat, and a dash of Fun Guy?

Pic 3 - the circles with the dip in the middle (the top part of the soap pic would make very excellent dragon scales )

Nah - no fun guy here. It could be wiped off as surface oil. Smelly surface oil.
I did wonder about the aloe too - this was an aloe soap - but I use aloe in pretty much every batch ( unless I've used coconut milk or oat milk) and have had no other problems with it.