In the process of saponification

Hi to all,
I am immersed in soap making, I am testing saponification with naoh and koh with different oils, with cold and hot processes, in my home.
At first only read about it, later i began to calculate the formulas and later i discovered the calculator. I think I understood everything well, but i am not able to find any information about this:

I don´t know if a soap, for example, with this ingredients:
water, sodium hydroxide, olive oil, coconut oil.
Could be better, worse or the same for skin than other with the same formulation and this ingredients:
Lavender infusion, sodium hydroxide, olive oil (infused with lavender), coconut oil, lavender essential oil.

The same for other ingredients:
honey, oat milk, rose water, flower extracts, propolis, myrrh, fruit... etc, etc.

I could experiment with this, but i don´t know if this is a useless thing.
I don´t know if I will know the difference just by trying it on me.

I have not found anything explaining, whether the process of saponification or such a high Ph, kills the properties of plants or anything we add.

Any scientific study? Can someone explain it to me or put me at the beginning of the road?

Thanks for reading.


  • All of these fancy bits and bobs should/must be added to the completed soap, not introduced during saponfication.

    Adding materials other than those required for the saponifying reaction will introduce all sorts of unknown and potential undesirable side reactions.
  • Adding plant materials is generally disappointing when making soap. This is because the high pH oxidises them and the matter just turns brown or dark brown. Do experiment though to find out.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • "All of these fancy bits and bobs should/must be added to the completed soap, not introduced during saponification".

    I guess i must investigate more, I appreciate these clarifications:
    is difficult for me to explain myself in english what i really want, sorry if i don´t achieve.
    how can i know in my home with no material when the soap is completed? 
    i think the soap would be hard at this point. Are they somehow added when the soap is hard? Is it so? if not, are added when the reaction is still fluid?

    thank you for your advice about undesirable side reactions, because I would not like , i think you are meaning about harmful interactions for health or dangerous for physical or material safety? or other kind of reactions or effects. I know the basics reactions for safety, but no further.

    @johnb Felix qui potuit rerum cognoscere causa.

    Sincerely thank you.

    Agree Belassi, at this point i will continue until i have an own opinion, and try a lot of things! Thank you!!

    Happy for learning a lot in this forum.

  • Really if you want to add organic materials you would be better off using the hot process, then adding the extras in at the end. Just follow the hot process and it will be obvious when the process is finished.
    With cold process it really isn't possible unless you add the extras during saponification and then they'll really get degraded by the free NaOH. I tried all this when I learned soapmaking.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • Now it is clearer for me, Belassi, i was wrong thinking that hot soap process is finished when it is hard. Thanks for that note. Measuring the ph confirms, now is obvious hahaha.
    I have followed hot process using the same formulas i used (in hot process too) but adding some organic ingredients, for comparing . Waiting to see the results.
    Very gentle. Greetings.
  • KloeKloe Member
    Hi everyone,
    i left my soaps with KOH because i found i didn´t like the foam they made (i have read about ricinus oil and in a future i´ll try it)
    I wanted the people that used my soaps made from NaOH tell me wich they liked more, but each people liked different soaps by different reasons and I could not come to a conclusion. But of all the soaps I have made, personally there is one that I like very very much and trying to understand why and what is the difference with the others, I think it is because it carries a higher proportion of saturated fatty acids, well, that is what I think by now.

    Now I would like to use NaOh and KOH in the same formula, using lots of butters and oils, but I do not know how it is calculated. Yes, there has to be a mathematical logic for this, but I can not find it.
    I've made a very basic formula to make it easier for me to understand (with three oils) and go around and around (calculating the percentage of each ingredient in the formula, calculating the percentage of NaOH that saponifies each % of oils ...), but I'm really stuck on this and I don´t want to use the saponification calculator.

    Thanks for reading

  • Bill_TogeBill_Toge Member, Professional Chemist
    potassium hydroxide has a molecular weight of 56 g/mol, and sodium hydroxide has a molecular weight of 40 g/mol

    therefore, as far as the saponification reaction is concerned, 1.4 g of KOH is equivalent to 1 g of NaOH (because 1.4 = 56 ÷ 40)

    as an example: if you'd normally use 10 g of NaOH in your formula, and you want to replace it with a 1:1 mixture of NaOH and KOH, you'd need 5 g of NaOH and 7 g of KOH (7 = 5 × 1.4) 
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • KloeKloe Member
    Thank you so much for your explanation!! Now it will be easier for me to continue. My new potassium hydroxide has 89% purity and I will have to recalculate, but I do not see problem.
    Oh Bill and I think I've understood where the values of my saponification table of oils and fats come from, I think they are calculated with the molecular weight you have given.
    Thank you, thank you.
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