Behenic (C22) and arachidic (C20) fatty acids in soap?

[Rune]

Hi y'all!

I bought rapeseed wax a while ago, but have not used it yet. I don't know the manufacturer or any other information about it, other that is says on the package "Hydrogenated Rapeseed Oil". To contact the UK supplier and ask for more details about their rapeseed wax, that is worthless, since they will not reply at all (I know that for sure, but it is a long story).

So, I went online to find 1) a saponification value for hydrogenated rapeseed oil and 2) what fatty acids it contain.

I found a sap. value ranging from 200-240 KoH. BUT, I did also find that hydrogenated rapeseed oil contain 42-50% behenic acid (C22) and 8-10% arachidic acid (C20).
(Maybe some hydrogenated rapeseed oils have different compositions, for all I know).

For example in this link (just do a page search for hydrogenated rapeseed oil, and you will find it): http://www.beauty-review.nl/wp-cont...ived-Fatty-Acid-Oils-as-Used-in-Cosmetics.pdf

I have never heard of those fatty acids before (I know nothing about fatty acids in general), and I have of course no clue about what type of soap they will produce, and if I will run into problems by using hydrogenated rapeseed oil as a 10-20%-ish part of a soap. I could not find it out anywhere either.

I could also not find too much information about using hydrogenated rapeseed oil in general in soap. I find some on this forum (I have not really searched for that elswhere). Lets say you make a soap with 100% hydrogenated rapeseed oil (or any other higher percentage), would the behenic and arachic fatty acids give good qualities to the soap or would it be a disaster? I guess that it probably does not matter too much if rapeseed wax is used in a low % of the recipe. But it would be interesting to know what those to fatty acids give to soap, good or bad?

I could try and see what happens (apart from eventual seizing) if I use hydrogenated rapeseed oil in a higher percentage (over 50% perhaps). But, before I waste lye and oils and hours of work + weeks of waiting time to see if anything strange happens during or after curing, I thought I could rather ask here first.

If anybody have any knowledge about what those two fatty acids do in soap, especially behenic acid which can be as high as 50% in rapeseed wax, that would be superb! Thank you in advance

 

[Becky1024]

Hope I can help! I'm a soap maker and also a chemist. Behenic acid and arachidic acid molecular structures are very similar to palmitic acid and stearic acid which are components of commonly used oils and butters in soap making. You will probably find that it makes a very hard bar and has a creamy lather. I think it will be conditioning too since behenic and arachidic acids have a long carbon chain.

I have not used hydrogenated rapeseed oil, you might want to make some small batches at a couple of levels (say 10%, 30%, 50%) and see what you like.

 

[Rune]

Thank you so much, Becky! Wow, close to palmitic and stearic, hard bar with creamy lather + conditioning, that is more than I could ever hope for

I need to test a full bar of my uncured, cut yesterday soap and not the thin sliver I have been testing. I think I probably can use that same recipe and add a perhaps 10% hydrogenated rapeseed oil to improve it further (and go down a few percentages on the soy wax). But I must really test my new recipe first, to see what it needs and don't need. I probably should wait until it has cured, at least a little bit, because it will change. But, no, let's head to the bathroom!

Thank you again

Yes, it is what I thought, it needs a more shaving foam like lather. It needs slightly more hard oils and less soft oils. Perhaps a little less coconut and castor as well, I'm not sure. But I think the coconut must down a bit, for sure. I know the lather will change during curing, but I have found that it changes to bigger bubbles and less dense lather. At least the latest two of my soaps have done that. So, I will go down a tiny bit on the soy wax and include rapeseed wax, and make the total waxes 10% higher than before. That should be roughly 12% rapeseed wax in the new recipe and 18-20% soy wax. Probably a good starting point to try out the new wax, or hydrogenated oil, which is what it actually is.

I am closer to finding a recipe that I like. I see that when I now tested the new uncured soap. I had never used soy wax before, so I assumed it would not be as good as my previous soaps with a type of vegetable lard full of shea butter, since I had not worked on the amounts of this and that, just guesstimated up a recipe in a hurry, and the amounts of soft oils were higher (since I didn't dare to use to much soy wax, and there is no other hard oils to find in this country, except coconut). But, it turned out amazingly good. It just needs some tweaking to be perfect.

When including rapeseed wax so that the total waxes will be around 30% might lead to rapid thickening. But I think it will be manageable, if I work in a hurry. I'm anyway accustomed to rapid thickening, so I don't panic too much, just makes a horrible mess.

 

[Fiona Robertson]

This is very interesting, thanks for posting this! Sorry if this is a daft question but how will you enter rapeseed wax on a lye calculator?

 

[Rune]

Yes, that is a good question. I did try to find something similar as that in a lye calculator, but could not find it. I can see one more time, just press every oil and see if something have a saponification value of 200-240 KOH. And I can see if I can find a more specific value somewhere. But we need to get it into the lye calculator one way or another.

I did not look close enough last time, now I find many we can use. I will write them all down and post here.

A sap value ranging from 200-240 Koh, will be around 220 Koh as a middle value. And we probably should go slighly less, to minimize the risk of making lye heavy soap.

Here is what I found on SoapCalc that will fit. I would use either Japan Wax or Palmitic Acid. Both have 0,215 Koh and 0,153 Naoh in saponification value. But, both those have two have high hardness and creamy values + high INS. Since rapeseed wax is close to palmitic and stearic acid, I checked the numbers for stearic acid, and it is the roughly the same, high hardness and creamy values + high INS. So that is common for both stearic and palmitic acid.

So, if we put Japan Wax or Palmitic acid in the lye calculator, that numbers for hardness, creamy, bubbly, INS etc will not be completely off, as it would if we choose something else. Japan Wax is probably the easiest to remember, at least for me.

Here is the list of what I found, so you can pick another one if you like (sap.value are in Koh):

Japan wax, 0,215
Palmitic acid, 0,215
Saw palmetto oil 0,220
SoapQuick, conventional and organic 0,212 and 0,213
Tamanu oil, kamani 0,208
Ucuuba butter, 0,205

I get really confused by all this numers that are crazy different. But I think it is relatively safe to say that rapeseed wax most probably have a sap. value around minimum 0,190 plus/minus. Why? Because Seifenrechner By Katrin in Germany operates with 0,190 for rapeseed oil (SoapCalc have 0,175) and that is quite some difference. I think both are right. But I think we should trust the European values for rapeseed oil more than the American. Grown at different continents and most likely from another variety of the plant. I'm quite sure one use Brassica Napus and the other Brassica Campestris. They have probably not the same sap. value. The 0,190 value from Seifenrechner by Katrin is most likely not just something she have imagined, because:

Katrin writes in the FAQ-section:

"I try very hard to gather the right values, ask directly from manufacturers, etc. If you still discover any deviations or mistakes, please let me know so that I can check the values."
(Translated from German in Google Translate)

But our rapeseed wax may come from America, China or elsewhere apart from Europe, and then the 0,190 may not be the one to use.

I will google up a more accurate scale, and then try to titrate the rapeseed wax I have. It must be possible to find at least one exact value. But then I anyway will need to find out if my rapeseed wax is 100% hydrogenated rapeseed oil and nothing else, otherwise we are not any longer.

To titrate mine will take some time because I'm not rich and I have to buy an accurate enough scale for titration, probably from China to save some money, meaning long shipping time.

I found these rapeseed waxes from KW-Chemie in Germany:

http://www.kw-chemie.com/index.php?datei=seite&seite=20&nav=15

They all have sap. values from 0,180 - 0,200. That will be 0,190 in between, the same as rapeseed oil when using a German lye calculator. And, then it is just as DeeAnna said, about the same value for hydrogenated and non-hydrogenated oil.

I will use 0,190 for my rapeseed wax, since I don't know if there is anything added to it that might make the sap. value be higher. At least I will use it until I manage to titrate it (unless I have used it all up by then and must buy more from another supplier).

Kokum butter or Kpangnan butter can be used in lye calculators, they are both conditioning, creamy and hard, so it will be not too bad to just pick one of those. I will use kokum butter, just because I misspelled kpangnan three times when trying to type it in here

 

[DeeAnna]

I agree with Becky. Palmitic is C:16 and stearic is C:18. Higher molecular weight, straight chain fatty acids will tend to reduce solubility, add longevity, mildness and hardness, and create a dense lather. Benhenic C:22 and arachidic C:20 acids aren't so greatly different than stearic.

I question the high saponification value that you're finding for this hydrogenated oil. Unless there is something in rapeseed "wax" that is greatly different than the non-hydrogenated rapeseed oil, the hydrogenated version should have a sap value about the same as the non-hydrogenated oil from which it is made (about 0.125 NaOH sap value).

All you're doing with hydrogenation is removing double bonds in the fatty acids, so the sap value shouldn't greatly change. It just doesn't make sense that the sap value should be almost as high as palm kernel oil, given the higher molecular weight of the fatty acids in the hydrogenated rapeseed.

 

[Rune]

Thank you, DeeAnna

I'm glad you questioned the high saponification value, it would not have been too fun to make lye heavy soap.
I can only speak for my rapeseed wax, and it says "hydrogenated rapeseed oil", so I have to think it is just that without anything else added or done to it. I can try to call the supplier and ask where they have got their rapeseed wax (if they answer calls, I doubt. Needless to say I will not use that supplier again. I'm glad I received any goods at all, but it was not without struggle and eventually claiming my money back from Paypal, first then they shipped it). Anyway, if I can find the manufacturer or wholesale supplier, I can probably get more information. But for now I just have to assume it is hydrogenated rapeseed oil and nothing else with no additives.

The saponification value from 200-240, I found in this link, at page 04 (the first mentioned on that page): https://www.in-cosmetics.com/__novadocuments/251087?v=636045203828500000

I found the same number another place also, but can't remember exactly where.

Anyway, typos or wrong information can easily sneak into webpages, so yes, I will use the listing for rapeseed oil, or unrefined canola or what the have called it in the lye calculators, until I perhaps get another saponification value directly from the manufacturer.

Thank you for clearing this up

 

[Fiona Robertson]

Gloopygloop got a KoH number of 0.206-0.214. from the Soap Kitchen but we both contacted Kerax and they couldn't supply us with any information

 

[Rune]

WOW, WOW!!! I'm shocked! Fluid soap, can you imagine! I'm sold on that rapeseed wax, for sure.

I have never had anything looking like fluidity in my soapmaking, except for my very first soap that was not a complete disaster (I guess it was my third or something around that). It was a castile soap, I did not have a stickblender, not fragrance, not colors, no nothing. I used my stand mixer and had to whip it on full speed for 2-3 hours, first then I was halfway sure it was traced. But after that one, no, it have been ONLY crazy accellerating soaps (and one full seize). Until today, when I made soap with my rapeseed oil. That was so fluid I can not believe it.

I was 100% sure that I could barely touch my stickblender. But I really had to more than touch it today to be sure I had emulsion. I'm not used to such things called emulsion, I'm used to thick pudding just seconds after lye goes in, so I had a little hard time recognizing it. Luckily the sun was shining on top of my batter, so I could see when it stopped being oily on top anymore, and I stickblended a few pulses more just to be sure. I don't know if I had thin trace or emulsion, but it was one of those two. I know it was not medium trace, because it made no marks on the top when I tested for that.

I did something different today than what I have normally done. I used a high amount of water (30% lye solution) plus added more water in form of mica dissolved in it. I did not use clay either. And I soaped at room temperature-ish. I think my oils were around 30 degrees C and my lye something around there, probably or cooler (I did not test it because it was in a big bottle, not easy to test). My micas shaken up in water was kept in the fridge for two reasons - I made them in advance and don't have distilled water, so I had to chill them, and I have heard that cold water added to thickening batter will help it loosen up a bit. I guess that made it even more fluid, because my batter was like water, almost, after I had mixed the colors in.

I had planned a drop swirl. I probably could have done allsorts of fancy things people do with their fluid soaps. But my head could not think of anything else, so I just made the drop swirl. Which by the way became very swirled because of how thin it was when poured.

Yes, I did another thing different, I added my fragrance at trace. I had found that it most likely should be non-accellerating. But I added at trace so I could see if the fragrance made any difference or not. It didn't, other than perhaps make it even more fluid. I used Green Fig from Eroma, at 4% of the oil, and boy that is a fabulous fragrance! Fruity and fresh. I have found that it must be the same fragrance as Green Fig from Brambleberry. The notes are exactly the same.

Well, down to the relevant part here, rapeseed wax. I used it at 30% of the oils, and used also 5% soy wax, just to get more hard oils. My oil mixture were fluid at room temperature, but it was thicker and whitish at that temperature. I did measure when my oils began to become thicker and white, and if I don't remember wrong it was at 26,5 - 27 degrees C. When it never got any harder than just a little thicker and whiter, as if you had stirred in lye, I began to see a hope that this soap might not accellerate like crazy. But I could not believe it, so I had everything planned for the average run-for-your-life to get it in the mold, and I was prepared to make a mess like no other. But I did not make any mess, and I had plenty of time to wipe it up as soon as I messed a little. That is very not like it use to be around here.

I'm not exactly sure how slow moving my soap were, because after it was molded and sprayed and placed somewhere warmer, I went outdoors and celebrated with a big glass of cola light and 2 cigarettes (yes, I know). When I got back in, my leftover soap (it was quite a lot, because of the high amount of water), which I had scraped over in one of the cups, it had solidified, or at least was not any fluid anymore. It was probably around 25 minutes after I molded the soap.

So, after this experience I'm totally sold on rapeseed wax (but I don't know how much of the fluidity is due to the wonderful rapeseed wax, or that I did use more water, less castor, no clay, cold temperatures and a new, cheap stickblender). I'm not sure if I have enough of it left for another soap, because I did not order much (I ordered mostly soy wax and just a little bit rapeseed wax, just to test it out).

But, fluid or not, the big test is to find out how the finished soap performs and feels.

My rapeseed wax recipe for today was as follows, for a total 1000 grams of oils:

Oil mixture:
Olive oil 45%
Rapeseed wax 30% (used kokum butter in the lye calculator)
Coconut 15%
Castor 5%
Soy wax 5%

30% lye solution
3% superfat
Dual lye: NAOH/KOH ratio 94%/6%
4% fragrance added at trace
3 colors mixed in roughly 1 - 1,5 tbls of water each
1 Mica-line mixed in roughly 1-1,5 tbls of oil
Temperature: Roughly around 25-30 degrees C.

Additives in the lye:

Vinegar 100 grams (I used a 35% strong vinegar equivalent to 100 grams 5%. I did not discount the water for my strong vinegar)
Silk (2 cocoons)

Additives in the oils:

5 grams EDTA in water (probably a tablespoon or so, maybe a little more)

 

[Fiona Robertson]

Congratulations on your success with rapeseed wax!! I'm interested to hear that you added soy wax for hardening, as i was told by a candle making friend that rapeseed wax was much harder than soy wax which is why I used it in low amounts. I'll look forward to hearing how you like yours after cure. I found that using a lower water amount eliminated soda ash but it still took a reasonable time to trace. An 8 week cure also makes a world of difference. Despite how much I love my rapeseed wax soaps, I decided to take a break from making them because of all the unknown quantities so now I am following your experiments with great interest!! Using dual lye is intriguing too.

PS. Are you ever going to tell us what the man from the soy wax company told you, I'm a bit scared to hand my soy wax soaps out to family in case something bad is going to happen!

 

[Rune]

I did do something stupid as well, very stupid. I did not make a top at all, just left it as it was after the drop swirl, and made some drops on the top with the remaining mica in oil. I sat it in a plastic shoe box in a sunny window to gel. It did gel and all that, but the oil drops on the top would not at all be absorbed into the soap. I got impatient and threw it in the oven for CPOP. I waited and waited and waited, and took it out, but it had still not absorbed. And some other oily liquid was also on the top. I thought I could cover it with cling film and put it in normal room temperature, hoping it would be forced to be absorbed. I did remove the cling film just recently, and it was really oily on top, but the dots had been absorbed by the soap.

I thought that it must be the fragrance oil coming up since I did stir it in at trace, instead of blending the fragrance with the oil before I add lye, as I normally do. I have to run to the other room and smell the oily liquid, to find out if it is fragrance or not.

Then I thought it could be from the mica line I swirled in with one of the colors. Maybe the oil from that mica line had come to the top?

Then I tried to find the answer on this forum by searching for "oily film on top". Now I see that I most probably overheated the soap in the oven.

I should have just left the soap as is and hoped the oil from the mica-line-dots would be absorbed in over night. I guess I thought the soap would absorb it as soon as it come into gel. I'm sure I did not think clear at all.

But, I also found that it might be perfectly allright, just leave the soap and see if everything absorbs back. I am a bit nervous about the cutting, since I perhaps have some signs of overheating inside. We'll see.

Anyway, I have learned not to be that impatient. It does not solve anything, just makes problems.

Rapeseed wax, maybe some manufacturers make a very hard ones and other not so hard ones? I bought mine at Mother Nature Goodies in Wales. They do write that their rapeseed wax is this and that, I can't remember exactly. I think it was a mix of fully and partially hydrogenated rapeseed oil.

I mean, maybe some manufacturers use only fully hydrogenated rapeseed oil, and will get harder waxes than others, perhaps?

Yes, I forgot everything about the mail I got from a technical manager at Cargill, and have not replied to him yet, which I should have done ages ago. Nevertheless, he wrote:

"Thank you for your enquiry.

The saponification value for C1 is about 190 mgKOH/g and for C3 about 193 mgKOH/g. The C3 contains some additives which also have a saponification value, so this is my best estimate but I don’t have a measured value.

Can you explain why you want to make soap from these raw materials ? They both contain partially hydrogenated vegetable oils, which from my experience give quite unusual behaviour after saponification (I guess due to the trans fat content) ; soaps are more commonly made from a combination of hard fats and liquid vegetable oils, often with some 15-20% of lauric oils like coconut or palm kernel.

For example, a typical hand soap is made from a blend of 80% tallow fat or palm oil, with 20% coconut or palm kernel oil.

I hope this was helpful,"


So this was the strange thing that I have never seen mentioned anywhere: "They both contain partially hydrogenated vegetable oils, which from my experience give quite unusual behaviour after saponification (I guess due to the trans fat content)".

I wanted to ask him about his experiences and write post here about it (if he allows me). But I never came so far. And I am very curious abut the saponification of trans fat from partially hydrogenated oils. How do they saponify compared to non-trans fat? Yes, things like that. And hear if anyone have noticed any unusual behavious when using oils with trans fat, like soy wax (and probably all or most waxes that are made from oils).

So, as you see there is no reason at all for you not to hand your soaps over to family. I'm sorry that I gave the impression that something strange might happen. It will not, at least not after the soap is done, cut and cured. Maybe before, I don't know. I will have to reply to him, I need to find out about this. What exactly have he experienced? And is he sure it's from using partially hydrogenated oils, and not him doing stupid things like I do, put things in the oven to make overheated soap, for example?

I have tried to google saponification of trans fat, and probably some words around that, but have not found out anything about it.

 

[Fiona Robertson]

Well all I can say is that I do not like working with soy wax. Maybe its because I cannot find 100% soy wax in the UK and none of the companies that I have written to will tell me what it is blended with. Almost every batch I have made just looks a bit odd although it performs well I find rapeseed wax to be much more cooperative but it is just a bit unknown at the moment. I'm looking forward to hearing how you get on. Thanks for the reassurance too

 

[Rune]

They write some info in the description for the wax that I have:

https://mothernaturesgoodies.co.uk/...ustainable-wax-for-container-and-jar-candles/

Not that I will straight up recommend buying from them, because I had some problems. But I got my products in the end, and maybe it was like they said, they were out of castor and had to wait for it to arrive before they sent any order. I don't know, but it probably was, because the castor came in a separate shipment a while after the other things. But the problem is that they really don't respond on any contact form or email. I got answer first when I claimed my money back because not receiving any products, and it was not even sent. Nevertheless, I want to buy from them again, since I now know how beautiful this wax was to soap with. But on the other hand, it was quite short dated products I got, at least the soy wax was (I don't think the castor was short dated, I think the rapeseed was, but don't remember exactly), so if I get that again, I can't buy in the quantity I want. I don't know what to do, really, other than I need to buy more rapeseed wax one way or the other. But I have my soy wax I can use in the meantime, and some more rapeseed wax.

Yes, that is a problem with candle waxes, it is not easy, if not impossible, to know what it contains. But if it is dermatologically safe and 100% soybean or 100% rapeseed, it should be okey enough. Additives can for example be stearic acid from soybean oil. Then it will still be 100% soy wax. It can be some unsaponifiables from the same oils, or something like that.

Maybe they don't want to tell anybody what they have added and not, and what their exact blend really is, because competitors can then copy their wax's outstanding properties. Maybe they want to protect their invention of a wax that solves this and that problem for customers. I don't know, but it can be something like that.

 

[Rune]

I now discovered, when I was to shut the side from Mother Nature Goodies, that my rapeseed wax does not at all look like what they have pictured. Definately not. Mine is not in beads like that, but in big, cut up chunks. If it is supposed to look like that on the picture, I'm a little suspicios, what did I really get? Probably chunks cut up from rapeseed wax they have bought in big bulk, I hope.

 

[penelopejane]

To CPOP soap preheat the oven to 110*F and TURN IT OFF. Wrap your soap in a blanket and put it in the oven and leave undisturbed for 12-24 hours. Do not open the door for 12 hours. Put a big sign on the oven "soap inside".

 

[Fiona Robertson]

would love to see pics of your soap when its cut

 

[Rune]

@Penelope, I will write you an email, have just not come so far yet. I had visitors the day after I got the email, and last night I smelled all my fragrance oil. Can you believe that I had not opened many bottles? I though I had, but I had not. So I did it yesterday, and took some notes. I do have some recommendations for you, but I will do another test first, since it is not accurate at all to smell from the bottle/cork. I have gone thru all the papers I recieved from you, and I really, really appreciated it. Just what I was looking for. They had not tested most of the scents I have, but I will buy new ones and I now have this register of how they perform, smell like and so on. Thank you 1000 times

I was the most stupid person that even thought of putting my soap in the oven. It does not help that my oven is super strong and heats up higher than what it should. I removed the soap from the mold just now, and peeled off the wax cloth lining from the sides. It does have signs of overheating. But, the oil on to have absorbed in 100%. So I will leave the soap as is for a few days and see what happens. So, Fiona, I will not cut it just yet. But the top is relatively nice. It is not really a top, just the drop swirl as is, the only thing i did was to add dots with the remaining mica line (the colour is burlesque pink mica). Some marks after the cling film, that stupid me used, but it will not show when cut.



But yes, it was the most stupid thing ever to pop it in the oven. It did not need that at all. I don't know what I was thinking.

If I will do that ever again (hopefully never again), I now know how to do it. So thanks for the advice

Here you can see the overheating I did:

 

[Becky1024]

Well Rune that was an interesting comment from Cargill about soaping with trans fats and partially hydrogenated fats. I wonder if he knows something we don't? I've never tried using Crisco, but many soapers do, and it contains partially hydrogenated soybean oil and used to contain trans fats, and from what I hear makes pretty good soap.

 

[Rune]

Yes, it is very interesting. I must mail him and ask more. Yes, I wonder what he knows and not knows too. I will mail him immediately.

I have read mixed things about Crisco, that it is great but also that it can make soap full of DOS. We don't have Crisco here at all, so I have not tried it.

 

[Rune]

I have replied to him, so we'll just have to wait and see if we can find out what it is all about.