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Lather Lovers: Additive Testing

The biggest part of soapmaking that I enjoy is formulating and testing. Trying different formulas, additives, fragrances, and colorants adds up to a lot of testing over the years.

Last year, I finally branched out and started getting in touch with the vast soapmaking community online. Before that, I was on my own. Many years ago, I had stumbled across Kathy Miller’s website which was my introduction to soapmaking. After devouring all of the information she had available, I set sail and started charting my own course – testing and formulating on my own.

If I had joined in on the small (but very much so out there!) soapmaking community online back then, I probably would have saved a ton of money on testing (as soapmakers tend to be very eager and happy to share all of their results.)

This year, on The Dish (which is an amazing forum full of soapmakers and soap lovers), I joined a swap with the sole purpose of testing different additives and their influence on lather.

Each of the soapmakers who joined in made the control formula with the addition of one additive during the week of January 1st, 2012. This ensured all the soaps were of similar age and formula, leaving the additive the only major variable between each bar.

Each soapmaker received a bar from every other soapmakers batch, leaving us with almost 30 different bars and additives to test and ponder.

Click the image to view each sample and it’s additive information!

We tested the following additives, as listed below:

  • Control Formula (8% Superfat: 50% Olive Oil, 25% Coconut Oil, 25% Palm Oil, Distilled Water)
  • Control Formula with 5% Superfat
  • Sodium Lactate
  • Granular Sugar
  • Honey
  • Silk
  • Rosin
  • Bentonite Clay
  • Tetrasodium EDTA
  • Reconstituted Goats’ Milk Powder subbed for water
  • Aloe juice subbed for all the water
  • Canned Coconut Milk subbed for water
  • Powdered Coconut Milk
  • Beer subbed for water
  • Fresh Goat’s Milk subbed for water
  • Evaporated Milk
  • Powdered Sugar
  • Kaolin Clay
  • Cetyl Alcohol
  • Oat Milk
  • Yogurt
  • Sorbitol
  • Sodium Citrate
  • Palm Kernel Oil subbed for Coconut Oil
  • Kefir
  • Sodium Citrate & Sorbitol

Interested in the results?

Sodium Citrate & Sorbitol Testing

I cataloged all of my results via my Flickr photostream. Included in the photostream is the base formula, additive usage rates, and lather testing results with 10 and 20 seconds of at the sink usage.

Shannon from Scenter Square also took video of her sink tests and posted them on her YouTube channel, if you’d like to see real time results.

Over the weeks (in between other testing and formulating), I’ve been working through more rigorous usage of the samples to get a better feel for how the additives affect the formula itself. Does Rosin make a formula more drying? (Yes!) Does Palm Kernel Oil subbed for Coconut Oil make the soap feel different? (Not by much!) Do animal proteins, like those found in Goat’s Milk or Yogurt, make a formula more moisturizing? (Varies!)

In a few months, I hope to share more extensive results when I get through with testing!

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36 Responses

  1. Every time a want some inspiration or look for some information about soap making, it is sure that i ‘ll pass from your site… Congratulations and many thanks for the offered informations and knowledge!!!

  2. I watched all of the suds videos with great interest — thinking at the time, “Anyone seeing me would think I was nuts! Watching Shannon wash her hands over and over. . . .” However, I learned so much. I can’t believe this amazing resource — thank you!!

  3. the learning never stops …I’m glad to have watched both of you , and watching both of your hands prune up ? priceless. πŸ™‚

  4. Hello Kenna, have you published further results on your findings? I belong to a soap swap group on fb, “Swaptember” and would love to present this as a potential swap. Would you mind if I used your idea? I would be referring everyone to this post of course, so they’d know where the idea came fom. Looking forward to reading more about it!

    1. Hi Stella! I did a second round of testing at the two year mark, and most of the results were similar – just slightly amplified on lather. πŸ™‚ This was a swap hosted The Dish forum, it wasn’t my idea at all. πŸ™‚ I’m sure it’s perfectly fine to do it with your own group!

      Thanks for stopping by!

  5. Excellent testing! These test results are an exceptional resource for us amateur soapmakers. It will definately save me alot of time choosing the best additives! Looks like I’m a honey, sugar and goats milk kinda gal – like a nice soft lather since the water here is very pure! Cheers.

  6. Thanks for this. I am very interested to know the results of additives, including different oils in soap. How drying is it, and how much lather. I am NOT interested in making a slew of soap to find out. Good you have a group to do it with you. Glad to know PK flakes are really no different than coconut oil. I’m wondering if there is in lather?

    1. Hi Janine! The Flickr photo album and the YouTube video linked in the post show the soaps use + lather. πŸ™‚ Sorry about the broken photos at the moment, we had a recent data glitch and I’m going through and fixing everything. πŸ™‚ Thanks! Kenna

  7. Very interesting article . in this regard I would like to ask you how you added the rosin in soap ? you used method to cold? thank you

      1. I personally did not make all the soap samples in this testing. πŸ˜‰ It was a swap, where several soapmakers made single batches, and then sent each other samples to test.

        If I remember correctly, the soapmaker who made the rosin soap melted the rosin into her oils as a 3% additive. I do recall her saying it moved lightning quick.

        I could be entirely wrong, this swap happened three years ago.

  8. Thanks again for your testing.

    I wanted to ask, does Sodium Citrate make the bar harder, too, like Sodium Lactate does?

  9. Hi there, I am having some issues with adding honey to my soaps. (cp soap). What say you?
    I would love to have a soap that really smelled of honey. without using fragrance oils. Do you know the best way to add honey, and how much would be the safest amount.. I am finding my bars to be a bit sticky and are taking ages to firm up..

    1. Hi Sarah. Way late to the comments on this one, but I belong to several soap making groups and have been making soap since 2005. There are very few additives you can add to soap that will scent a soap all by itself. Honey isn’t one of them. I’m sure you’ve found help on the “how to add it” question, but there are lots of ways that work. Add at light trace is probably the most common. I use 1 to 2 tsp per pound of oils in the recipe. Add too much and your soap will overheat and volcano out of the mold. Not fun. Sticky and long to firm up might be about the honey (if you are adding a LOT) but its probably mostly about your other ingredients (the types of oils used, how much liquid). Good luck. Highly recommend the Soaping 101 Facebook group for help on questions like this.

  10. Awesome experiment πŸ™‚
    Thanks for this information…

    was just wondering how would I substitute Palm Kernal Oil? would a mixture of cocoa butter & beeswax work?

    Thanks Neena

  11. Hi Kenna,

    Your sight is a God send. I am trying to create my own M&P base but I can’t get the lather where it needs to be.

    I love your bar 10# with the use of Aloe.

    My question is what do you mean when you say “SUBSTITUTED FOR FULL WATER”?

    This would really help me out.

    Thanks in advance.

  12. Thank you for all your effort in educating. Could you please tell me if I need to add a little more water when I use bentonite clay and activated charcoal. Is that 1 table spoon per pound of oil is correct ?. Thanks

  13. I made soap from base and pour soap, I put coconut milk in it , maybe too much . Now it does not lather can you tell me what I can do now before I throw it out ,Eike

    1. Hey, Eike,
      Melt & pour soap bases can absorb only a limited amount of additives. You supplier should be able to tell you what that amount is. With the info you gave me, I can’t be sure, but it sounds like you may have overdone it and ruined this particular batch. Next time follow the recomendations for additives. πŸ™‚

    2. As you have probably found out already…Unfortunately, with Mrkt & Pour soap you can not add things like milk or purΓ©ed vegetables/fruit because the soap has already gone through saponification. If you add liquid (fresh or canned) milk or even aloe juice to melt&pour soap it can go rancid and Frie bacteria and fungus. It’s best to buy melt and pour soap already made with coconut milk or other additives you want. Or you can try Cold process and add whatever you like because it will go through saponification and turn into actual soap. You can also try Hot process. Goodluck with future endeavors and Happy Soaping ☺️

  14. Sorry for the typo.
    16 and 18 are wrong and number 19 is missing. But thank you for the info. I get told in the forums to read so I guess I’m reading too much..I find that the beginners on there really are not beginners so it’s hard to get some info on certain HP reciepes. Thank you for all the info you put out for us!

  15. Thank you so much for this post, I have been looking all over for this kind of information and this is such a great experiment! I absolutely love the idea of group testing like this, it’s a wonderfully creative way to go about it. I loved looking at the various pictures and you’ve really helped me decide on my additives πŸ™‚

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