Soap turning orange all over.. DOS?

[szaza]

So a while ago I made some soap from some old wheat germ oil that I superfatted at 0% with the intention of trying to rebatch with some other soaps. Now, about 7-8 weeks later I wanted to do the rebatch, but found the soap to have an orange color all over on the outside, but when I cut it it was still cream-colored on the inside.
My first thought was that the lye purity was probably not 100%, resulting in a slight superfat that turned rancid. But isn't rancid soap supposed to make spoys, not just color all over the outside? I had just opened a new can of lye, so impurity should be minimal. My scale measures with 0,01g precision, though my recipe was rather small (213g of oils) so there might be some slight error of measurement. The soap also doesn't smell particularly nice, though it it never has from the beginning since it's wheat germ oil soap
Has anyone had the same thing happen? And is it rancid soap or something else?

IMG_20181011_092156

• szaza
• Oct 11, 2018
• 1

DOS?

 

[Obsidian]

I'd say yes, that's rancid soap. It does usually start as spots but can and does eventually spread to the whole soap.

Wheat germ has a short shelf life, using old oil on top of that is a sure fire way to get dos. You should always use fresh oils for soap.

 

[shunt2011]

I too think it's definitely DOS. I wouldn't do anything with it. And as Obsidian said you should always use the freshest oils possible and longer shelf life as well.

 

[szaza]

Thank you for confirming my suspicion!
I had read that some people 'safe' oils from the trash by soaping at 0% superfat so there are no fats left to go rancid. I tried to do that with the wheat germ oil, but apparently I must have had some hidden superfat.. Would it be an option to try -1% superfat next time?

 

[shunt2011]

I think people try to clean the oil from what I've read. I just don't think it's worth the risk and wasted ingredients.

 

[szaza]

Luckily I only wasted a few grams of lye and some distilled water as I was going to throw the oil out anyway
What I understood/remember from the 'saving' process is that rancidy of oil/fat is fatty acids breaking off from the triglycerides. The idea was that if you make soap you break triglycerides up in fatty acids and glycerin anyway, so it doesn't matter if the oil is (about to go) rancid. You just need to make sure that all the fats are saponified. Apparently that went wrong with me last time and I'm wondering if a -1% SF would have been better

 

[shunt2011]

I can't help you with that. Sorry. I wouldn't use rancid oils to begin with. Maybe someone will pop in with more knowledge on that.

 

[szaza]

Thanks for your input anyway! Of course I try to use only fresh oils, but sometimes you buy a bunch of wheat germ oil on sale only to realize you never use it.. (I still have a 250ml bottle.. *sigh*)

 

[Susie]

Any old oil, at even a negative superfat, can lead to DOS as it goes rancid. There is no "saving" old oil unless you just want to throw the soap out to start with.

 

[DeeAnna]

^^^ True what Susie said. Low or no superfat will minimize the chance, but the soap can still become rancid.

Soap can certainly become rancid over all of the bar. If an ingredient or contaminant is mixed throughout the soap and it triggers rancidity, then all-over rancidity is the outcome.

The spots of rancidity that people call DOS are caused by discrete, individual bits of contaminants. This can spread to all-over rancidity or just remain spots.

If you want to use a rancid fat for making soap, you can certainly do that. Soap makers didn't and still don't always use edible fat to make their soap -- some of the sources of fat used for soap would gross most of us out. But in times when fat is needed as food, it would be foolish to use only edible fat for soap.

It's best to wash a rancid fat with water before soap making to remove some of the aldehydes, ketones, and other chemicals that make up the rancid portion of the fat. That will improve the smell and keeping qualities of the soap after it's made.

If you have the option to also add an antioxidant (rosemary oleoresin being an example) to the fats before soap making, that would also be a good idea to slow down the processes of oxidation and rancidity in the finished soap.

"...rancidy of oil/fat is fatty acids breaking off from the triglycerides..."

Yes, it's true that this happens, but fat is not rancid at this point -- it just has a higher acidity due to the build up of these free fatty acids. Fat at this stage is still mild smelling and fine to eat or use in soap.

What you'll see if you make soap from a high-acidity fat is that the soap will come to trace quickly, because lye reacts very quickly with the free fatty acids. If you have ever made a shave soap with stearic acid (a fatty acid), you know what I'm talking about. Sometimes edible fats with high acidity are treated with a mild alkali solution to remove these free fatty acids and thus reduce the acidity of the fat.

Rancidity starts when the free fatty acids continue to chemically break down into aldehydes, ketones, and other chemicals. This is the point when soap or fat turns color and develops an odor. When the odor and color change become noticeable (the nose is very good at detecting this odor), then the fat or soap is officially rancid. It's a natural process of decomposition, so one can't expect to ever stop this chemical breakdown of fat, one can only slow down the process.

 

[szaza]

Thanks @shunt2011 @Susie and @DeeAnna for shedding some light on the matter!
I do find myself wondering now what rancid soap actually is. I always thought it was the superfat that turned rancid within the soap. Do the ketones and aldehydes break off from the fatty acid chain of the soapsalts? If so, what does that mean for the actual soap, does it start to behave differently because the chain is now shorter?
Is rancid soap safe to use? I always thought it was mainly an aesthetic/smelly mishap, but I can imagine ketones and aldehydes aren't super skin-loving ingredients. (I know my skin does not like aceton for example but then again, the concentration will probably also be important I guess?)
If it's of any value: the wgo I used did not smell really bad (though I don't care for the smell even if it's fresh) but it was past the sell-by date.

 

[NsMar42111]

Oil does make a good weedkiller where you dont want stuff growing...dumped a bottle of rancid veggie oil out and hey no weeds there...or grass....or life...

 

[DeeAnna]

I suppose rancid soap isn't exactly dangerous to use, but it's certainly objectionable. It will leave a bad odor on the skin and hair. I suppose the breakdown chemicals might be irritating to the skin, but I haven't researched that so I can't say for sure. It's sufficient for me to know that I do not care to wash with rancid soap nor eat rancid fat.

 

[Susie]

I made the mistake of washing my hands with DOS soap just to test out what kind of feel it gave to the soap. Took me days to get the smell off my skin. Ewwww...........

 

[shunt2011]

I toss it. No way would I use it personally.

 

[Tracy Paglione]

Oil does make a good weedkiller where you dont want stuff growing...dumped a bottle of rancid veggie oil out and hey no weeds there...or grass....or life...

Off topic question: If you use that right before winter on an area you want to to completely clear would you be able to plant there come spring?

 

[MKLonestar]

What happens then if you use oils that are past their "Sell By" dates? For example, RBO that has a Sell By date of 10/8/18... it smells perfectly fine. It has been used in the last week in several soaps, so does this now "shorten" the shelf life of the soaps that were superfatted at 5%? What does happen to the shelf life of a soap that is made with oils that have short shelf lives?

 

[DeeAnna]

Fats do not instantly become unusable if they're past their "sell by" date. That date is only a suggestion to help stores keep their inventory fresh, not a "nuclear bomb" deadline for consumers. Common sense is important as well as your nose.

A person's choice of storage conditions after purchase has a lot to do with how fast a fat becomes oxidized and rancid -- is fat stored in a hot attic and exposed to bright light or stored in a cool dark pantry or refrigerator? Also the use of antioxidants in the stored fat can make a big difference -- does a person add ROE (rosemary oleoresin) to fats after purchasing them?

I wouldn't use a "sell by" date to convict a fat as being the cause of rancidity. Only in a few cases, can I point to a specific reason for rancidity in my soap. In most cases, however, I have no concrete idea what triggered rancidity. My use of ROE in my stored fats and a chelator (EDTA) in my soap have really helped -- I can't recall any of my soap showing any sign of rancidity since I started using these additives.

As you have been doing, just use your nose -- it's useful, sensitive tester for rancidity. If a fat smells okay, use it. If it doesn't smell okay, then don't use it. If fat smells rancid, soap will probably also smell "off" and more prone to obvious rancidity.

 

[earlene]

I know it's late, but I would have used that soap as a hand soap, rather than tossing it. The inside was fine, so trimming the outer portions away and using the soap would have been fine, IMO. If it smelled off after the first washing, then I'd toss it, but not without first trying it out.

But then, I don't really like the smell of wheat germ oil in the first place and maybe I wouldn't like the smell of the soap to start with anyway.