My Liquid Soap

[Lankan]

I made a small batch of (1kg) CP liquid soap and used Brembleberry soap cal to decide the lye mix. My oils are Palm oil 340g, Sunflower oil 159g and 85g of Coconut oil. the Calculator directed me to add 131.14g of KOH on 367ml of water (0% superfat). However after soap traced , small about 50~100ml water separated and the leftover became transparent . However, when I diluted it on water to use I noted it to be very high in pH value (13~14, I used the pH strips). I was wondering what could have gone wrong.. I've attached the recipe printed from the calculator.

When I added the same list of oils on other soap cals the those indicates differing amount of KOH to be used. For example. according to Certified-Lye.com SAP values it is 121.3g, FromNatureWithLove.com, it is even less 119.5g and thesage.com soap cal indicated 120.07g of KOH. I wonder why such inconsistency. Also trying to find out the standard SAP values for the oils.

Also I would appreciate any advise that can help to reduce the pH value of the batch I've made.

 

[DeeAnna]

Most pH strips are highly inaccurate with soap, especially how most soapers use them. So the reading you are getting is most likely not correct. The pH, even if measured accurately, is not a reliable indicator of excess lye -- the free alkali test and the zap test are the two methods to determine that. Very few soapers use the free alkali test; many of us use the zap test.

Soap naturally has a pH roughly between 9 and 11, with the correct "natural" pH varying depending on the blend of fatty acids in the recipe. If you add acid to soap to try to get the pH lower, the soap will break down chemically into fatty acids. Liquid soap will tell you the pH is too low by forming a layer of white fatty acids on top of the diluted soap.

Moving on -- every soap recipe calculator is based on assumptions and estimates, whether you create your own calculator or use someone else's. Saponification values and fatty acid profiles are determined by measuring real fats, which are natural products that vary somewhat. My advice is to pick a calc and get used to it -- don't keep switching and comparing the various answers.

Another issue if you are going to compare the results from various calcs is to make sure you enter the exact same recipe in every calc. You used a zero superfat in the BB calc. Did you set the superfat to zero for all the others? (I didn't take the time to figure this out. But I do know most calcs are set to a default of 5%.) If you didn't, that could easily explain the higher KOH weight from the BB recipe versus the lower KOH weights from the others.

If you want more information about your fats, then get away from the Bramble Berry calc. This calc hides a lot of useful information to make it seem more user friendly for beginners. I recommend Soapee.com as a calc that's easy to use but also full featured.

 

[Lankan]

Thanks for the response. I have not heard about the Zap test. I'll try to learn from the internet. I did wash my hands few times with the hand wash and experienced a tiny layer to skin in my palm and fingers peeling off. So, I thought the reading from the pH strip is reliable (even if not so accurate). Also I tested the pH in the bar soap which i made two months ago, and the reading was around 8~9. I previously read about acids breaking down the soap. hence didn't try it.

Do you think allowing the soap to cure for about a month would help?

With regard to SoapCalc, i thought of using multiple, in order to ensure that I'm not adding too much or too little lye. I think always factoring 2~5% superfat should at least allow the effect of excess lye to reduce isn't it.

Edit 1 : By the way read about Zap test, but feel like doing it.

 

[shunt2011]

Sticking to one soap calculator will keep things consistent. You're overthinking it. Soap Calc is reliable. If you have too much lye it's generally a measuring problem not a calc problem. Soap is naturally a ph of 9-10 so there's no worries there. Zap test is the easiest way to see if there is excess lye. PH won't tell you if its lye heavy.

 

[bumbleklutz]

As far as calculators go I like soapee.com. It is full-featured, and gives you a ton of information; yet it is very easy to use. SAP values are really just averages, so don't sweat it when you see different values for the same fat. Consequently, different calculators will end up giving you slightly different lye amounts. Usually, a gram or 2 difference is not a big deal. As far as PH testing is concerned it really isn't that reliable when it comes to soap, and truthfully doesn't tell you all that much about the quality of the soap. A higher PH soap can be quite mild, while a lower PH soap can be harsh. As others have said, any PH between 9 and 11 is normal. Zap testing is a better indicator of unreacted/excess lye. Instructions for zap testing can be found here: https://www.soapmakingforum.com/threads/how-to-properly-safely-conduct-the-zap-tongue-test.63199/

 

[earlene]

Lankan, are you sure of your scale's accuracy and have you reviewed how to use it to avoid errors? That is where I would look first to see if the scale or user error was involved.

How old or young was the liquid soap when you washed your hands with it and experienced skin peeling? I would certainly be concerned about that and wouldn't use it again on bare skin until a negative zap test was performed. I suggest wearing gloves while doing the zap test, too, by the way.

 

[DeeAnna]

...I did wash my hands few times with the hand wash and experienced a tiny layer to skin in my palm and fingers peeling off....

If that happened, then I'd say the soap is indeed lye heavy. You didn't include any superfat according to your recipe, so that may have been the problem. It's just as likely you made an error due to a measuring mistake, or an inaccurate or low precision scale, or something. It's hard to know the real reason at this point.

As far as time solving the problem of a lye-heavy liquid soap -- It's certainly an option to try, but be aware this might not work as well to reduce lye heaviness in liquid soap as it does for lye heavy bar soap.

Zap test method: https://www.soapmakingforum.com/threads/how-to-properly-safely-conduct-the-zap-tongue-test.63199/

With regard to SoapCalc, i thought of using multiple, in order to ensure that I'm not adding too much or too little lye....

If you don't trust a particular calc, then don't use it. Getting answers from multiple calcs is not a useful solution -- use one reputable calc and stick with it. In the English speaking world, Soapcalc and Soapee are both good full-featured choices. There are many other reputable calcs out there in English, Spanish, Japanese, and other languages.

In your case, I think if you had used the BrambleBerry calc to create a recipe with 3% superfat rather than zero superfat, your soap would probably be fine.

 

[Lankan]

Thanks all, your advises are indeed very helpful. I tested pH about 6 hours after making it and diluted with water. last night tested the pH again and seems to have little lower pH. I've used a Kitchen scale to weigh the ingredients. Like you all suggested Soapee and SoapCalc seems to be very detailed an informative. I might use it on my next batch.

I've rechecked the purity of the KOH with the vendor, They claimed it to be 99%. the BrembleBerry calc states that it assumes 90% purity for KOH and 97% purity for NaOH. I guess the error happened due to this only.

Why I wanted to use multiple calc is due to the fact that if I had rechecked my lye with another Calc I may have noticed the difference and could have avoided it.

My learning from this batch are,

- Always include superfat, (I never included in the past)
- Pay more attention to lye (amount, dilution, purity etc)
- Learn to do zap test

 

[earlene]

Your lye absorbs water from the air everytime you open the container, and the longer the lid is off, the more it can absorb. If your environment is very humid, it can absorb even more moisture from the air. Therefore, the purity of the lye decreases over time as it becomes exposed to room air (or whatever air you expose it to. Some folks mix their lye outside.)

In any case, the purity of the lye on the date of shipping is not equal to the purity of the lye after its been opened multiple times by the consumer.

There are tests you can do yourself to verify the purity of you lye. See this video tutorial by our member, DeeAnna explaining how that is done:

 

[Lankan]

Hi all. I had diluted small portion of the above soap into approx 100ml liquid. That's the portion I used to test pH value. This weekend I've checked the pH and it seems to have improved, also did a quick zap test (with lot of nervousness). Didn't feel anything zapping. Hoping to do it again next week.

In addition I used the table salt yesterday to thicken the liquid which was watery at first. Now it has turned out to be a creamy soap but lost out the transparency. But I loved the way it looks now.

 

[Lankan]

I've been using the diluted portion of the soap for about a week, I also got someone else also to try just to see how he felt compared to other liquid soaps. The soap produces good lather and bubbly, however it leaves a oily feeling in the hands. Actually have to wash the land longer in running water to get rid of the oily feel or use another soap to wash it off.

Can I be due to the water separation I had initially,?