Can Liquid Soap Base Go Rancid ?

[DesertRose]

Hello,

I made this base on 05.12.2023, approx. 2 months ago. It was being stored at room temperature in a closed plastic container. When i opened the box in order to dilute some to make liquid soap, i was encountered with this scene,

The upper layer was gone to brown even chocolate colour and the smell was not bad but stronger than usual. When I go deep inside, i realized that the colour of the middle layer and below is just fine.

When i dropped the base into hot water, the colour of the water went to blueish first and than like this,

A little darker than usual.

The only difference in this batch comparing to my previous formulations is the type of olive oil i used. I had changed my olive oil supplier actually not supplier he's a farmer and growing his own olives. He told me that this oil has less acidity profile and more suitable for drinking. Yes, I live in Olive Oil Paradise, Türkiye

Do you think this soap base is safe to use ? Can i use it for hand washing at least ?

 

[DeeAnna]

Yes, any soap can go rancid. Rancidity in only 2 months is unusual, but certainly possible.

I'd discard the dark top layer. Whether you dilute all of the remaining paste or keep some undiluted, be aware that this remaining soap is more likely to go rancid. I'd get it used promptly. Your nose will tell you if the soap is rancid or not.

 

[DesertRose]

Yes, any soap can go rancid. Rancidity in only 2 months is unusual, but certainly possible.

I'd discard the dark top layer. Whether you dilute all of the remaining paste or keep some undiluted, be aware that this remaining soap is more likely to go rancid. I'd get it used promptly. Your nose will tell you if the soap is rancid or not.

Thank you. What can be the reason for rancidity ? Storing conditions, low quality oils or any other ? How should i store the soap base ?

 

[AliOop]

Did you happen to use a fragrance oil with vanillin in it? If so, the top layer could also have discolored due to the vanillin. If that's the case, then subsequent top layers will also discolor when exposed to the air inside the bucket. I've found I can limit this somewhat - not completely - by tightly covering the top with a layer of plastic wrap, so it has less contact with the air inside the bucket.

 

[DesertRose]

Did you happen to use a fragrance oil with vanillin in it? If so, the top layer could also have discolored due to the vanillin. If that's the case, then subsequent top layers will also discolor when exposed to the air inside the bucket. I've found I can limit this somewhat - not completely - by tightly covering the top with a layer of plastic wrap, so it has less contact with the air inside the bucket.

I use Pachouli & Vanilla fragrance oil but not on the base, after dilution.

Thanks for the tip and your contribution

 

[AliOop]

I use Pachouli & Vanilla fragrance oil but not on the base, after dilution.

Thanks for the tip and your contribution

Yup, the vanillin would have to be in the base to discolor the base. Since that wasn't the case, you definitely had some form of oxidation or rancidity going on there. Sorry!

 

[DeeAnna]

Factors that increase the chance of rancidity: Long cook time. Metallic contamination in the oil, water, alkali (KOH), or other ingredients. Contamination from equipment and utensils. Storage in hot conditions. I'm sure there's more, but that's all that come to mind quickly.

Store soap paste and diluted soap in a dark, cool place. Some people freeze or refrigerate the soap paste for long term storage. They will dilute the paste as needed, so there isn't a lot of diluted soap in storage. Use an antioxidant and/or chelator to lengthen the shelf life.

 

[DesertRose]

Factors that increase the chance of rancidity: Long cook time. Metallic contamination in the oil, water, alkali (KOH), or other ingredients. Contamination from equipment and utensils. Storage in hot conditions. I'm sure there's more, but that's all that come to mind quickly.

Store soap paste and diluted soap in a dark, cool place. Some people freeze or refrigerate the soap paste for long term storage. They will dilute the paste as needed, so there isn't a lot of diluted soap in storage. Use an antioxidant and/or chelator to lengthen the shelf life.

I have KEM-EHG as preservative. May be i should use it ?
INCI NAME: Phenoxyethanol, Ethylhexylglycerin.

 

[DeeAnna]

I have KEM-EHG as preservative. May be i should use it ?
INCI NAME: Phenoxyethanol, Ethylhexylglycerin.

Don't have a clue. You need to check the manufacturer's information to verify the preservative is suitable for high pH applications. If it is, then you need to learn whether it is an effective broad spectrum preservative or if it needs to have a co-preservative.

But a microbial preservative is not the same thing as an antioxidant or a chelator.

We've been talking specifically about rancidity in this thread, so are you thinking this preservative can provide antioxidant or chelating benefits?

 

[DesertRose]

Don't have a clue. You need to check the manufacturer's information to verify the preservative is suitable for high pH applications. If it is, then you need to learn whether it is an effective broad spectrum preservative or if it needs to have a co-preservative.

But a microbial preservative is not the same thing as an antioxidant or a chelator.

We've been talking specifically about rancidity in this thread, so are you thinking this preservative can provide antioxidant or chelating benefits?

According to manufacturer;
Effective Ph range: 3-12
Protection range: Broad spectrum
Type of protection: Against bacteria, yeast and mold.
Usage Range: All type of cosmetics including soaps and hair-skin care products.

 

[DesertRose]

Hello again. I managed to save my remaining soap paste. The middle and the bottom layer is just fine. I diluted it and added preservative.

Now i have another problem. Normally i use Polysorbate 80 for my fragrence oils to solubilize in liquid soap. Otherwise a white layer occurs at the top. But my supplier has run out of Poly 80 stock, he has only have Poly 20.

What can i use as a substitute to Poly 80 ?