Beginner's Question

Soapmaking Forum

Help Support Soapmaking Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
"...Also, according to Kevin Dunn's experiment a high superfat or a large lye discount doesn't contribute to DOS...."

I have learned a lot from Dunn's Scientific Soapmaking book and his articles. I have read Dunn's report about his DOS experiments, and I do accept his findings are valid within the context of his experiments. I think his experiments may stop short of a full explanation of DOS, however, and I also feel some of his conclusions in this papaer are not fully supported by the data.

I also feel his research is sometimes taken a bit out of context. What Dunn actually says about the superfat experiments is this:

"...From the color saturation curves in the two following graphs, we can see that, indeed, the 10% discount soap does eventually become more orange than the 0% discount soap. But looking more closely we also see that the induction period is about the same, 75 hours. Even at 0% discount the soap becomes noticeably orange in about the same time as at 10% discount. Since our goal is to prevent orange spots altogether, we should not look to changing lye discount as a cure for them..."

He assumes that overall color change in the soap is tantamount to the development of rancidity and DOS. That assumption might be correct, but his experiments did not go on long enough to confirm it. The experiments ended about 2 weeks after each soap was made, so the data in his published research do not support his conclusion that color change = DOS.

His paper also shows an experiment measuring the color changes for a 100% coconut oil soap and a 100% olive oil soap. Both soaps show a pattern of color change that is similar to the superfat experiment. The CO soap changes color quite a bit less than the OO soap. Both soaps, however, show a distinct increase in the rate of color change at the 50-75 hour mark -- this increase in the rate of color change is something he calls the "induction point".

In the superfatting experiment, Dunn points to the overall color change and the presence of the induction point in the 0% and 10% superfatted soaps to justify his conclusion that superfatting does not "cure" DOS. Fair enough.

But the CO and OO soap experiment shows similar results as the superfat experiment -- the experiments both show the soaps had a color change with a clear induction point. So why didn't he conclude that using CO is not a "cure" for DOS any more than 0% superfat is not? If there was an explanation that justified this apparent discrepancy in his conclusions, he didn't present it in the paper.

I also do not see in Dunn's data any real connection between the soaps' overall color changes in the first 2 weeks with the appearance of actual DOS, if and when it ever appears. If overall color change in the first 2 weeks is indeed a warning sign of DOS, then I really want to see the experimental results that show that correlation.

As a trained researcher myself, these are the questions I ask myself whenever I re-read Dunn's paper on DOS. I do see the good in what he is doing to dispel myth and superstition about soap. I do see intriguing and interesting trends in his data. In the end, I really do not think the data in his experiments fully support some of the conclusions he draws in this paper.
 
Last edited:
Thanks so much for helping everyone!
I was probably thinking large batch because I brew beer so I'm always doing the largest batches possible. Good advice in this situation since its experimental. I'll start with a 2 gal. batch
I had a high castor % because I suspected the soap might be soft and I thought castor would harden it but I'll drop it to 5%
One of my many problems is I don't know what a superfat is. I could'nt enter it in the calc. because I didn't know what it was. That's why my lye is off. What is a superfat and what % should I use? I thought normal is only 5 to 7%.
I'll drop my sunflower oil down to 10%
I'll take a chance and leave the grape seed at 5%.
I'll jack my Olive oil up to 35%
I'm so stoked. I went to Goodwill yesterday and got a 2 speed oster stick blender $5.00 Working large crock pot $10.00 Tall plastic cont. for mixing lye $1.00 Large Pyrex glass bowl for mixing oils $2.00. However it will still be a week before my cocobutter arrives in the mail so I still have time to tweak my recipe.
Have a great day. Tim
 
Last edited:
Just an FYI, Castor Oil does nothing to harden soap. From what little I've learned so far, my understanding of superfatting is adding more oil than necessary to combine with lye, leaving some fats left over after the 'reaction'. Some superfatting is a good thing. It gives you a little 'play room', so you'll be sure all your lye has been converted. Also the oil left over helps moisturize your skin....I think. Most people seem to hang around the 5-15% superfatting, for most recipes. Of course, there are exceptions to this. It all depends on what you want/like. The very first batch I made was 100% coconut oil and it was superfatted at 18%. If I had only superfatted it at 5-10% it would have been very drying to my skin. Sounds like you got some good deals!:thumbup: I know how you feel about having ALMOST everything, but not quite, and waiting on that last item, to make soap. I'm in the same boat right now. lol! I'm trying to keep myself entertained by reading up on how to make swirls and such.:cool:
 
Hey Hazel! or DeeAnna! or just whoever happens in here, who is knowledgeable about DOS. Is there any time frame, that IF DOS is going to happen, it will happen? (I'm sure that's terribly clear! lol!) What I mean is, after you make a batch of soap, is there a time frame that after that period of time has passed, you can breathe a sigh of relief and say..."ok, there's not going to be any DOS in this batch"...or could it suddenly spring up on a batch of soap say a year after it was made?
 
There are certain oils that have a much higher DOS happening than others. Soy, safflower, sunflower are some of the worst. It can happen any time from right after to 6 months later or more.

Now with safflower and sunflower you can get around it some is HO versions. But the key to any oil not going DOS is storing oils right. Most have to be kept cool and in a dark place like a frig. The hard oils most are OK at room temps even after opening for a few months, as long as room temps stay in the low 70 range.
 
I went to a soap calculator and readjusted. I put in 10% super fats, which I think should be good but it asked "Water as percent of oil weight 1-40" I didn't know the answer so I left it where it was at 38. Will this work or is it way off.
 
Kay -- I'm no expert on the subject, to be honest. I just like to read a lot and I'm pretty decent at seeing patterns and figuring things out. So, with that out of the way, here's my personal point of view...

I don't think there is any point at which you can say DOS won't happen. Decomposition is a normal part of nature, and DOS is basically a form of decomposition. You want to minimize the possibility, of course, and Nebetmiw makes some good suggestions on that subject. But I think it's unrealistic to think of soap like the Egyptians thought of their mummys -- perfectly preserved for eternity! :D Whenever there is the right balance of oxygen + moisture + fat + energy, there is the potential for DOS.

That said, I do find myself wondering if the incidence of DOS in most handcrafted soap is most likely within the first 6-12 months after a soap is made. That is when the water content is highest and most of the chemical and physical changes from the curing process are happening. But that is just my opinion, not proven fact.

I wish I had the ability to do research on this, because I think a lot of good can come of studying DOS in handcrafted soap and the specifics of how and why it forms (and how to minimize it). Kevin Dunn has done a good job of getting the ball rolling, and I respect his work on the subject. Others need to keep the ball going, though, and add to his contributions.
 
You mean we aren't apt to find any petrified Egyptian soap?:lol:
Thanks for the info nebet and Dee!:thumbup:

To tom: I have no idea about the 38 on soapcal. I've always assumed that was the normal and have always left it at that. I'm afraid to change something I have no idea about! lol! What does that mean anyway?

P.S. I sure hope the OP doesn't mind us stealing their thread! :wink:

Just thought of something else. I have two batches of soap that I've made so far. I have both batches in separate crocks. Is storing soap in a crock ok? I have them in my bathroom closet and one I put saran wrap over the top, the other I just put a clean washcloth over the top. I thought it would work ok, but does the soap need to be able to breathe or anything?
 
Last edited:
tomatotim - 38% is right where it needs to be. Later, after you 've made several different kinds of soap, you can start to adjust that percentage down so that you're using less water, but for now leave it at 38%. I still soap at 38% if I'm going to be doing a swirl or a zebra stripe. When you soap at 38%, you have enough liquid (water or beer or whatever) to keep the batter from getting too thick too quickly. I've been soaping several months and (usually) know what to expect from some of my tried and true recipes, so if I'm doing a plain Jane bar with no color, no scent, no swirls or other designs - then I will adjust the calulator to 33% or so.
 
Chicklet
thanks so much. As soon as my cocobutter arrives I can start now I know my recipe is ok. My soap will be on the soft side but it should work.
 
Just thought of something else. I have two batches of soap that I've made so far. I have both batches in separate crocks. Is storing soap in a crock ok? I have them in my bathroom closet and one I put saran wrap over the top, the other I just put a clean washcloth over the top. I thought it would work ok, but does the soap need to be able to breathe or anything?

_________________

Kay! Mostly, I'm curious how you're going to get those soaps out of your crockpot. Not to mention, you're now going to have a big round mold shape, rather than any kind of rectangular, easy bar cutting shaped mold. I am curious to see what anyone else might have to say on the subject, though.
 
Just thought of something else. I have two batches of soap that I've made so far. I have both batches in separate crocks. Is storing soap in a crock ok? I have them in my bathroom closet and one I put saran wrap over the top, the other I just put a clean washcloth over the top. I thought it would work ok, but does the soap need to be able to breathe or anything?

_________________

Kay! Mostly, I'm curious how you're going to get those soaps out of your crockpot. Not to mention, you're now going to have a big round mold shape, rather than any kind of rectangular, easy bar cutting shaped mold. I am curious to see what anyone else might have to say on the subject, though.

I'm not storing them in a crock pot, I'm storing them in a Crock(.) You know, those things grandma used to use? My soaps have already hardened and have been cut into squares.
 
Last edited:
Just thought of something else. I have two batches of soap that I've made so far. I have both batches in separate crocks. Is storing soap in a crock ok? I have them in my bathroom closet and one I put saran wrap over the top, the other I just put a clean washcloth over the top. I thought it would work ok, but does the soap need to be able to breathe or anything?
.

Yes, it needs to breathe in order to lose the excess water. Storing them out on a rack is the best option IMO. The Dollar Store has cake racks really cheap.
 
What Ruthie said is spot on.

Another idea that seems to be working okay for me is lining a low, open cardboard box (such as a "beer flat") with a clean cotton towel and putting my bars on the towel. If the boxes are a little bit taller than the bars, it is possible to carefully stack them, a few boxes high. I stagger the stacked boxes so air can circulate. Maybe not the prettiest, but it works.
 
In the end, I really do not think the data in his experiments fully support some of the conclusions he draws in this paper.

Good points but I don’t understand what you mean by your comment “In the superfatting experiment, Dunn points to the overall color change and the presence of the induction point in the 0% and 10% superfatted soaps to justify his conclusion that superfatting does not "cure" DOS”.

From what I was reading earlier, I thought people were saying superfatting isn’t the “cure” of DOS but part of the cause of it. Maybe I misread their posts. I’m not a scientist or trained researcher but I still believe a higher superfat doesn’t contribute to DOS based on what I’ve experienced. I use a higher superfat then generally recommended and I’ve only had one bar develop DOS. I’d only used a 5% lye discount in it but the soap was older than 12 months, possibly closer to 18 months. I’m also fairly sure this batch was one in which I had decided to use up some EVOO which had been in the cabinet for awhile. Normally, I try to make sure most of the oils are still fairly “fresh”, kwim? I also mainly choose more stable oils (CO, PO, OO, HOSO and castor) since I don’t make large batches and I don’t go through any of the oils very quickly. I use oils which aren’t as stable at a lower percentage (5%-10%) and I store them in the frig. There was a facial soap batch I made in which I used what are considered unstable or short shelf life oils and a high lye discount/superfat and the control bar I kept hasn’t developed DOS yet at 2+ years. This is all the time I will know about it since I broke down and am now using the bar. :oops: I also use mainly distilled water for regular batches.

However, I will state a higher lye discount/superfat has not been an issue for me but perhaps it would be for some people depending on where they live. I think there was a previous discussion about environment being a contributing factor. It can get very hot and humid here but when it does, I keep the drapes closed, turn on the A/C to kick on enough to keep the house below 80 F and use fans to circulate air. I set my soap on parchment paper or wax paper until it is cured and then store soap either in the bathroom towel cabinet, cardboard boxes lined with wax or parchment paper or in lined drawers in another bathroom.

Thanks for posting your observations. It would be interesting to see a DOS experiment followed over a longer period with more variables. I should try one if I can ever get the sewing room converted to a “soap” room. :lol:

Dunn’s info about additives might be helpful for people who are concerned about rancidity.
 
Hi, Hazel --

Thank you for pointing out my inconsistency. I should have written this "...to justify his conclusion that lower superfatting does not "cure" DOS...." A slip of the keyboard -- please accept my apologies for not being clear.

You make some very good points about using fresh oils, stable types of oils, using distilled water, and storing soap properly. I think there is no one single factor that triggers DOS -- it is a lot of things that all add up. All we can do is to minimize the probabilities, and it sounds like you are doing a great job of that. Thanks for sharing your point of view!

--DeeAnna
 
I believe that Alchemy & Ashes single oil experiment showed the same results with the grapeseed oil. You might could find her blog post. I have no personal experience with grapeseed oil.

I LOVE sunflower in leave on hand creams!!! But because of it being a soft oil and potential DOS I haven't ever tried it in CP. I do wonder now if I could find a small bottle of High O Sunflower oil. I surely would try it if I did.

I haven't ever tried the veg Crisco. But I love the hardness of tallow and lard also. So I do use the WM store brand shortening that is made with tallow and palm in some recipes. It does work great. I really don't use shortening of any kind as food though :/
I use Mid Olec Sunflower in most of my soaps at a percentage range of 10 -20%. When using sunflower I keep the superfat at 5% or in humid weather 3-4%. I also add roe in my sunflower oil when I purchase it. I love sunflower in soap. Grapeseed oil is hard to use over 10% unless you go a low superfat number, since it is such a soft oil, but it is a good low astringent oil that is non-comedogenic. I use it in my neem soaps @ 10%
 
Good points but I don’t understand what you mean by your comment “In the superfatting experiment, Dunn points to the overall color change and the presence of the induction point in the 0% and 10% superfatted soaps to justify his conclusion that superfatting does not "cure" DOS”.

I was thinking this too. However, it did seem like what she said seemed to be correct for the way Dunn stated his findings, under the quote she used. He used the same wordings (as I recall), about "superfatting not being conclusively a cure." Which I thought was a weird way to state the opposite in a conclusion statement.

I also use mainly distilled water for regular batches.

I actually use tap water at the moment. Mostly because we have exceptionally excellent drinking water, here. I'm happy to report that the recent attempt from our government to put flouride in overturned by a petition from our people, leading to a vote, making the act turned down. I'm not against people getting their proper flouride, but I don't approve of this method. That's beside the point. I do plan on using distilled water in the future, but it's not really an issue at this point. My point is that I haven't ever experienced DOS, and if the type of water has anything to do with it, it definitely isn't an issue here.
 
I should have written this "...to justify his conclusion that lower superfatting does not "cure" DOS...." A slip of the keyboard -- I think there is no one single factor that triggers DOS -- it is a lot of things that all add up. All we can do is to minimize the probabilities,

Okay! Now I don't feel so bad about being confused. I have to admit I sometimes skim posts and may not read them as carefully as I should. :oops:

You're right and I'm glad you emphasized there isn't a single factor. It's a good reminder for me to understand just because I don't have problems with certain oils, it doesn't mean other people won't based upon variables. I should start adding into every post "YMMV". :lol:

@ Lotus -

You just stated you have excellent drinking water. I would use tap water instead of distilled if I lived in a city which had excellent drinking water.
 

Latest posts

Back
Top