Superfat amount

[patka]

I would like to know if there is anyone who is using a lower percentage of superfat than 5% in soap.

I am having trouble with my soap getting DOS during the hot and humid Georgia summer. I never get DOS any other time, and my soaps that I took abroad into a mild climate have been doing fine for several years, but here during the summer, my soaps start sweating oil and eventually some of them will get DOS, regardless of recipe (there is no airconditioning where I keep my soaps). I will try to manage the issue by making less soap before the summer months hit, but I would like to see if making a soap with lower SF would help increase the shelf-life of my soaps.

I am curious to find out if anyone has tried a lower, say 3%, superfat and if yes, what was the soap like, will the soap maybe become too harsh if the SF is lower than 5%? I would be comfortable with 3% from the point of view of soap safety, since I usually make at least 4lb batches and I know the exact SAP value of most of my oils, but is the 5% SF that most people use needed to make the soap milder?

Thanks in advance for sharing your experience!

Edited June 9, 2010 by patka

[Rae]

I am in Georgia and I don't have problems with my cp soap. I do have 2 dehumidifiers in my shop, so I am sure that is why I don't have that problem. My dehumidifiers fill a large bucket everyday.

Have you considered buying one?

Rae

[8-GRAN-ONES]

i don't know what oils you are using..but sometimes oils like canola, safflower, grapeseed can cause dos if used in to high of %..

make sure your oils are very stable, and have a long shelf life..

espessially for the summer months soap..

[Kitn]

I use canola in some recipes , have never had DOS, but I do have a dehumidifier running, they are well worth the investment, it takes gallons of water out of the air everyday, and I live in a pretty "dry" climate.

[topofmurrayhill]

Prof. Kevin Dunn tried artificially ageing soaps made with 0% and 10% lye discounts. The results suggested that the more superfatted soap might get a worse case of DOS, but that the two soaps were equally likely to get it.

Susceptibility to DOS mainly depends on the recipe. Factors like heat and humidity might accelerate the process, but basically soft soaps are prone to get it and hard soaps are not. Avoid linoleic oils and keep the ratio of soft to hard oils within reason. Current handcrafting advice and a lot of recipes suggest inappropriate oils and too much liquid oil.

There are safe and effective stabilizers that will reduce the risk of DOS to virtually zero. Current fads may frown upon them, but in my opinion they simply increase the quality of the product. If you want to keep things natural, rosemary oleoresin extract apparently has some positive effect on stability, although it can affect the color and odor of the soap.

[chuck_35550]

My soaps will get slick when the basement humitdity gets really saturated. Living in Alabama is like the humidity capitol of the world (may be a close race with New Orleans) but I have never had a case of DOS. The soap dries back out with no noticeable problems. Some of my recipes border on dangerously high levels of iodine (like Top said because of soft oils high in linoleic fatty acids) but they have remained stable. Super fatting is just a safety measure because the numbers in calc are not absolute. You may be thinking about lye solution per centages or discounting the water and that's a whole different ball game. Neither of those solutions are going to change the nature of your soap if it incorporates lots of soft oils. IMHO.

Steve

[patka]

Thank you for all your replies. I agree that some soap recipes hold up better than others, but ultimately, after a few weeks at 100 F and near 100% humidity, the excess oil will start sweating out of most of them and sooner or later some of the soaps will develop DOS. I am actually not using any of the unstable oils and my oils are usually quite fresh.

I think my recipes are fairly balanced, maybe not very hard, but ok, usually around 55%-60% of hard oils. I usually use about 25-27% coconut, 25-27% palm, 5% some type of butter, 5% castor and the rest olive, sometimes olive and high oleic sunflower, (no DOS on the soaps with sunflower oil yet, since they are more recent)

The only soap that does not mind the climate is my laundry stick with 0% SF. The salt bars did not get DOS either.

One thing that seems to help is wrapping the soap (in cellophane, or cellophane bags, not in paper) before the heat comes. I don't see DOS on ony of the wrapped soap, so that may be a way to go for the future. I understand about the de-humidifier, but it is not an option where I have my soaps now.

I am surprised that even 0% superfat soap developed in DOS in the experiment that Top is mentioning. I thought it was the unsaponified fat that would go bad in the soap creating DOS. My thought process about the SF amount was that the less unsaponified fat in the final product, the less fat to go bad in the heat. Maybe it is the glycerin that is produced in the process then? I will still try to make soap with about 3% SF and see if it helps any. I just wondered if the soap will get harsher when there is less fat in the finished soap, but I guess I will find out when I make it. I think 3% SF is enough for the safety margin since I know the exact SAP value of most of my oils.

[topofmurrayhill]

The experiments seemed to indicate that the type of oil rather than the amount of unsaponified oil was the factor in whether soaps were likely to get DOS. The ones with 0% superfat didn't discolor as much as the 10% soap, but they discolored just as quickly. In contrast, formulations with more saturated fatty acids had a longer induction time. Since you have to store soap under adverse conditions, you could consider testing a recipe with less olive oil and see how it does. It could improve the quality of the product in other respects as well.

The original article is here. There's also a version of it in a new book.

If you feel that decreasing the lye discount could be beneficial, 3% sounds very reasonable. I often do that. There's generally enough of a safety margin in the SAP values and the moisture content of the sodium hydroxide. I suspect the actual superfat often ends up higher rather than lower than the lye discount.

Edited June 11, 2010 by topofmurrayhill

[patka]

Top, thank you for the suggestions and for the link to the article. I may try the rosemary oleoresin since it seems that it could help. I can try to reduce the amount of olive oil as well and then perhaps increase the amount of the hard oils. That will be some new experimenting for me, since I have usually kept the hard oils between 55-59%. I am thinking I can increase the palm perhaps.

I agree that the actual superfat in the soap is likely a little higher than we calculate, I have thought about that too, since the calculations assume the lye is at 100%, which it never is, mostly because of moisture.

But I understand from the article that reformulating the soap may be more effective in increasing the shelf life of the soaps (and the rosemary oleoresin as well), so I will try to work on that too.

Thanks so much!

[soycrazy]

The only soap that does not mind the climate is my laundry stick with 0% SF. The salt bars did not get DOS either.

My palm and coconut laundry bars, that are 0% SF have DOS all over them. My recent ones have a citrus eo blend in them and they started to turn so quick after this humidity hit and they are not a month old. My unscented ones did the same thing. I bought some ROE so I'm going to try them out with this, hopefully it works. My salt bars as of yet are fine also they just sweat a bit from this humidity.