My DOS Challenge Experiments

[DeeAnna]

Either sodium citrate or potassium citrate. Either one works.

I use 0.5% EDTA; I have not used citrate (either kind) as a chelator. Other people do. Most use sodium citrate. Here's the info I have gleaned from their contributions: https://classicbells.com/soap/citrate.html Also see: https://classicbells.com/soap/citricAcid.html

DeeAnna - are you referring to sodium citrate? How do you list this ingredient on your soap label? My recipe (with hemp at 6%) reflects Linoleic 11 and Linolenic 2. Would it be safe to say that using .01% ppo would help keep DOS away? At what phase would I add the citrate?

Sorry for all the questions but I've never used sodium citrate before.

Spice --

I wrote "... I store finished soap in covered containers or get it packaged in shrink wrap..."

To clarify, I keep young soap in cardboard boxes covered, top and bottom, with clean cotton toweling. That is the "covered container" I mentioned, and it is most definitely not air tight.

After curing, I package the soap in shrink wrap, but that happens 3 weeks or more after the soap was made. I also make a "sniffy hole" in the shrink wrap so people can smell the scent. So the shrink wrap is also not air tight.

But if I didn't need the sniffy hole for people, I probably wouldn't bother. The soap would be fine. For proof, just look at the pictures of Krista's soap in this thread that were wrapped in plastic wrap -- those bars aren't in bad shape.

I hope this clears things up.

You package your soap so it doesn't get air? Not to say its not done, its just that I have read that soap needs air to cure, so after cure it's ok?...

 

[KristaY]

I'm really glad this thread was resurrected as it reminded me to look at the soaps again. It's now been almost 2 years since they were made so it's been a long (unintentionally long, lol) experiment.

The soybean and canola soaps went into the trash last year because the rancid smell was just too much to tolerate. The soybean which had DOS spots that grew and multiplied, eventually turned orange. The rancid smell kept getting stronger. The canola never developed spots, just slowly darkened and got stinky. Binned 'em both.

The sunflower bars still look and smell fine except the EO blend is pretty non-existent. Not surprising since I've kept them open to air the last year.

The grapeseed bars have a bit of an off smell but no spots or color change. This doesn't surprise me in the least when you consider the shelf life of grapeseed oil. If I was in love with this soap I'd consider making very small batches that would be used in my household only. But since it wasn't blow your skirt up amazing, I'll stick with HO sunflower and be content.

Spice, I cure my soap open to air for 6-8 weeks then package in cello bags that are tied off, no air holes but not air tight. I like wrapping like that so various hands and noses stay off the soap. I also have sniffies (end cuts) that are in and out of zip baggies and handled by multitudes. I haven't had any problems with one or the other developing rancidity (like wrapped soap does and unwrapped doesn't, or vice versa).

 

[Spice]

I'm really glad this thread was resurrected as it reminded me to look at the soaps again. It's now been almost 2 years since they were made so it's been a long (unintentionally long, lol) experiment.

The soybean and canola soaps went into the trash last year because the rancid smell was just too much to tolerate. The soybean which had DOS spots that grew and multiplied, eventually turned orange. The rancid smell kept getting stronger. The canola never developed spots, just slowly darkened and got stinky. Binned 'em both.

The sunflower bars still look and smell fine except the EO blend is pretty non-existent. Not surprising since I've kept them open to air the last year.

The grapeseed bars have a bit of an off smell but no spots or color change. This doesn't surprise me in the least when you consider the shelf life of grapeseed oil. If I was in love with this soap I'd consider making very small batches that would be used in my household only. But since it wasn't blow your skirt up amazing, I'll stick with HO sunflower and be content.

Spice, I cure my soap open to air for 6-8 weeks then package in cello bags that are tied off, no air holes but not air tight. I like wrapping like that so various hands and noses stay off the soap. I also have sniffies (end cuts) that are in and out of zip baggies and handled by multitudes. I haven't had any problems with one or the other developing rancidity (like wrapped soap does and unwrapped doesn't, or vice versa).

I use soybean mainly as a filler. What other oil is there to take its place? Hmmmm.

 

[KristaY]

I use soybean mainly as a filler. What other oil is there to take its place? Hmmmm.

I'm not really sure what you mean by a filler. Is it due to costs of the other oils? Is it a certain property you want to achieve in your soap? I decided to take a look at soybean in soapcalc and this is what I found in regards to linoleic and linolenic FA's:

Soybean - Linoleic=50, linolenic=8
Soybean, 27.5% hydrogenated - Linoleic=7, linolenic=1
Soybean, fully hydrogenated- Linoleic=0, linolenic=0

Based on these values, you're safest using fully hydrogenated soybean oil. I have no idea if certain brands or suppliers offer the fully hydrogenated variety. In my experiment I used Wesson Oil. You want a high oleic oil and Wesson's is low oleic since it's about 21% monounsaturated fat. Here's the math based on the Wesson Oil label (thanks to DeeAnna):

Monounsaturated fat=3gms
Total fat=14gms

3 divided by 14 x 100=21.43%

If you live near Trader Joe's, look at their HO sunflower oil. I get a liter for about $4.00. Or you can just increase your olive oil or other soft oil.

 

[Spice]

I'm not really sure what you mean by a filler. Is it due to costs of the other oils? Is it a certain property you want to achieve in your soap? I decided to take a look at soybean in soapcalc and this is what I found in regards to linoleic and linolenic FA's:

Soybean - Linoleic=50, linolenic=8
Soybean, 27.5% hydrogenated - Linoleic=7, linolenic=1
Soybean, fully hydrogenated- Linoleic=0, linolenic=0

Based on these values, you're safest using fully hydrogenated soybean oil. I have no idea if certain brands or suppliers offer the fully hydrogenated variety. In my experiment I used Wesson Oil. You want a high oleic oil and Wesson's is low oleic since it's about 21% monounsaturated fat. Here's the math based on the Wesson Oil label (thanks to DeeAnna):

Monounsaturated fat=3gms
Total fat=14gms

3 divided by 14 x 100=21.43%

If you live near Trader Joe's, look at their HO sunflower oil. I get a liter for about $4.00. Or you can just increase your olive oil or other soft oil.

What I meant was, I use soybean to give me that extra added oil to complete my batch. I have had more people give me negative thoughts on the soy oil; so I need to look at some other oils to fill in the reminder of my oils to complete my batch, besides the DOS issue. I like the idea of sunflower oil, I do live near a Trader Joe's. I will be stopping by soon.

I like how DeeAnna, broke down how to get the fat %. That will be a note I use in the future too.:bath1:

 

[OldHippie]

Another major cause of DOS is storing on metal shelves and another is not letting the soaps get ventilation.

What makes you think so?

 

[Lin19687]

What makes you think so?

Can I ask why you seem to question everything?
There are a ton of posts about this.

And WHY are you bringing up YEAR OLD Posts ?
I mean it is great that obviously you are reading and searching but just start a new thread.

 

[psfred]

Rancidity in soap (what we call DOS) is a well known issue, it's discussed in century old text books. It fact, it is oxidation of the fatty acids, and while saturated fatty acids can oxidize, they are more resistant than the unsaturated ones with double bonds.

UV light will accelerate DOS quite a bit, even a highly resistant recipe will slowly yellow if left on a sunny windowsill. It's slow, but it happens, starting on the edges.

Metal ions, particularly iron, catalyze the oxidation -- that is to say, they contribute electrons easily as they can change "oxidation" state easily and are not used up. Chelators bind the metal ions and greatly reduce the effect, but will not totally prevent catalyzed oxidation, so one should use distilled water in soapmaking and avoid contact of the soap with metal items for extended periods.

The fats and oils used also can be more or less susceptible to oxidation, particularly animal fats. All of the first soaps I made with a batch of lard I had on hand have gotten DOS in some form. Took a long time (eight months for one) but they all got at least a spot or two. Those I made with a different brand are fine. The animal fats are rendered with heat, and it they are overheated or over oxidized during rendering, not only will they have an odor of cooked meat, they will already have some oxidized fatty acids present -- they contribute to the "cooked meat" odor. Needless to say, the presence of oxidized fatty acids seems to catalyze more oxidation,

I have started using citric acid, BHT, and EDTA in everything along with fresh distilled water. No trouble since I started using all this except that it's not possible to use indigo and BHT in the same soap -- the BHT reduces the indigo to nearly colorless.

Soaps made with Walmart tallow base shortening in any combination have remained perfectly DOS free, so I may be using a lot more of that in the future. Makes a very nice balanced soap all by itself too.

 

[cjisler]

Soaps made with Walmart tallow base shortening in any combination have remained perfectly DOS free, so I may be using a lot more of that in the future. Makes a very nice balanced soap all by itself too.

Oh, yes. I can concur with the Walmart shortening sentiment.
Carol in SC

 

[cmzaha]

What makes you think so?

I can positively say that storing and curing on metal shelves can cause problems with spots of DOS. I have always lined my chrome curing shelves but sometimes a soap would touch an uncovered side rail, which resulted in spots of DOS every time. Sometimes instead of arguing or questioning every answer a person gives you need to believe what experienced soapers have already experienced and know. Experience can be much more valuable than book learning at times....

 

[OldHippie]

Can I ask why you seem to question everything?

I look for facts to support a belief before I accept it.

There are a ton of posts about this.

Actually, I meant to edit out the "storing on metal shelves" part. Sorry to cause a fuss. Lye and metal can cause all sort of mischief together. It's the ventilation part that did not make sense to me on it's face. Given that rancidity is caused by oxidation, why would you want to maximize the exposure of your soap to oxygen?

And WHY are you bringing up YEAR OLD Posts ?

The post that I responded to was five days old.

 

[Lin19687]

Apr 27, 2017 is not 5 days old, that is the last post on this posting.
So not sure where you came up with 5 days old

 

[OldHippie]

Apr 27, 2017 is not 5 days old, that is the last post on this posting.
So not sure where you came up with 5 days old

Whoops. Actually the post that I answered was dated Jun 4, 2016. I overlooked the year. Sorry about that.