Does liquid soap develop DOS?

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May 28, 2015
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I've decided to delve into the deep waters of liquid soaps. Made one batch off a FB group recipe involving dual lye and it actually worked. I've been digging around at the 5 million recipes and methods and have a found a few to try (including the glycerin method) once my supplies come in.

In my travels I found a recipe that uses high corn oil percentage here

After digging through the forums here, I can't seem to locate any information whether or not liquid soap has the DOS issues with oils such as corn that bar soap does. So the question is.... does liquid soap develop DOS?

*goes back to the rabbit hole of liquid soaps*
Ok, so go with the gut and forgo the corn....... got it! Not sure I ever want to smell rancid liquid soap.

This rabbit hole is getting, and I thought bar soap was full of options!
As everybody else said, DOS on bar soap=rancidity in liquid soap. It stinks and you won't miss it. Also, depending on the application, you might want to avoid oils that have strong smells like tallow. They are harder to cover up. I make liquid soap with tallow and soybean oil for laundry with added limonene (1%). The wet clothes come out smelling like tallow and limonene but thankfully the scent disappears after drying. It works better than any commercial detergent I've bought.
"...Which oils don't go rancid?..."

Every fat will eventually go rancid, sooner or later. It's an unavoidable fact of nature. The better question to ask is which fats have a longer shelf life than others.

A fat that contains high levels of water, metallic contamination, organic matter, and other impurities tends to go rancid faster than the same type of fat with fewer impurities. Fats exposed to UV light, moisture, excessive warmth, oxygen, and sources of contamination will go rancid faster than fats protected from those things.

Fats with two or more double bonds (linoleic and linolenic fatty acids -- corn, soy, hemp, linseed, etc) will go rancid faster than those with only one double bond (oleic acid -- olive, avocado, etc). Fats with no double bonds (stearic, palmitic, lauric, myristic acids -- coconut, palm, palm kernel, lard, tallow, etc.) are more stable.

Ways to slow down rancidity -- Store your fats and soaps properly (moderate temp, dry, clean, away from light, reduce oxygen exposure). Avoid adding contaminants that may accelerate rancidity (trace metals especially). You can also add an antioxidant to your fats (vitamin E is not helpful, but rosemary oleoresin, ROE, works good) and/or add a chelator to your soap to bind up trace metals (tetrasodium EDTA and sodium citrate are two common chelators).
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If you want make a large batch of LS paste you can refrigerate or freeze the paste, and dilute it when when you need more

That's what I do. I scoop my paste into Ziplock freezer bags and store it in the fridge until I need to dilute more. Works great!

IrishLass :)
I've had pretty good luck just storing my paste in a covered tub in a kitchen cupboard. So far so good, anyways. I'm sure open to refrigerating the paste if that proves to be a better way to go.
I made a 1 lb batch of soap and divided the paste into tubs that, when diluted, would fit a particular bottle that holds dish soap. So, not so very much, and only two tubs left.
DeeAnna, based on what you stated would choice of containers make a difference plastic VS. glass? Then my question becomes what's in the body butters we find on store shelves that prevent them from going bad? There must be something in those that we could add to our's.
Body butters (and other B & B products) on store shelves are often loaded with many "chemicals" that we as home producers either:

A: Choose not to use. I am talking about the parabens and the other polysyllable ingredients listed at the end of every list of ingredients.

B. Can't get our hands on in small enough amounts so as to not have a metric tonne of the stuff lying around the house taking up space and costing a fortune.

Does that mean that you CAN'T use those? No, you can use those if you choose, and you can hunt down and afford to buy them. I choose not to. I have found a way to make a small enough batch to not have to worry about pathogen growth. I make a small amount, then re-package the paste in the proper amounts to dilute as I need it. The paste stores very well at room temperature.

However, I do have a small bottle of liquid soap that is nearly two years old. I check it under the microscope every now and then for pathogen growth. So far, so good. It contains no preservatives or anti-oxidants. I suspect it will go rancid before it grows germs. But surely two years is enough time for anyone to store liquid soap, yes?
"...based on what you stated would choice of containers make a difference plastic VS. glass?..."

The answer is easy -- The container needs to be plastic for safety. Containers easily slip out of wet hands, and glass is just not a sensible choice.

To answer your question directly -- As far as preservation of the product goes, I don't think plastic or glass makes a bit of difference. You would be better off to worry about choosing an opaque or dark colored container to keep light from degrading the product. That's one of the reasons why milk is often packaged in opaque jugs and beer and wine are usually in dark bottles, etc.

As for me, I use clear containers (inexpensive, easy to find) that are small enough so we use the product up in a reasonable time. I refill my containers from a larger jug that I store in a dark, cool cupboard.

"...There must be something in those that we could add to ours. ..."

Bear in mind, you can't STOP oxidation and rancidity -- that's no more possible than the Egyptian idea of preserving their mummies forever.

I already answered that question -- see Post 8. Susie makes a good point that the commercial products contain ingredients that home crafted products often don't have access to, and I also agree with her that many of those ingredients are really not necessary. Home crafters do have access to effective antioxidants like ROE and chelators such as citrate or EDTA to slow down oxidation and rancidity. You might want to think about using them to lengthen the shelf life of your products.

Whether you use theses additives or not, many of the practical things I outlined in Post 8 and that others have shared are also helpful to lengthen shelf life. Like Susie, I too have older soaps and lotions that have yet to go rancid and it won't ruin my day when they eventually do. If I wanted something that lasted "forever", then I'd buy the commercial stuff. That said, a hand crafter should easily be able to make a soap, lotion, butter, etc. that has a shelf life of well over a year just by making sensible choices.

"...This topic is really freaking me out...."

Protecting against rancidity is certainly an issue to be aware of, but it's not something that should make a person feel upset about. It's just a normal thing that happens all the time. In today's market, there's the idea that we should avoid germs, avoid dirt, avoid aging, etc. and we'll be healthier and happier and longer-lived when we do. It's just an illusion.
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