Last summer I developed five different soap recipes to test the idea that soaps with the same properties in the soap c@lculator (and similar fatty acid profiles, see below) will lather the same regardless of the sources of the fats. For each recipe, I started with a different palmitic and/or stearic-rich hard fat or hard fat combination. From there I added varying amounts of coconut, rice bran, high oleic sunflower and castor oils to all of the recipes and then added avocado oil as needed to match the FAs as closely as possible among recipes.
All recipes have the following properties in the SMF c@lculator:
Bubbly 17
Cleansing 13
Conditioning 52-53
Hardness 41-42
Longevity 29
Creamy Lather 33-34
And this fatty acid profile:
Lauric + Myristic 13
Palmitic + Stearic 29 (all palmitic dominant, but ratio varies among recipes from p:s 1.1 to 2.2)
Ricinoleic 5
Oleic 40-42
Linoleic + Linolenic 8-9
The palmitic and stearic-rich fats or fat combinations and palmitic:stearic ratios:
palm (no stir) + shea (refined); p:s = 2.2
lard (Armour brand); p:s = 2.2
tallow (Soaper’s Choice); p:s = 1.6
GW 415 soy wax + cocoa butter (unrefined); p:s = 1.2
cocoa butter (unrefined) + shea (refined); p:s = 1.1
Every recipe was made with aloe juice as a partial water replacement, sodium citrate as a chelator, Nurture’s 8th and Ocean FO and 2% superfat. The lye was food grade from Essential Depot. The soaps were color coded by adding different color swirls. (ETA: the soaps were made 8-11 August 2021; the testers identified the soaps by color; all testers knew there were five base fats/combos and the makers were given the FA profile and soap properties)
I sent the soap to 16 testers, including 10 “soap lovers” and 6 “soap makers.” Each tester was asked to score the soaps from 1-10, with 10 being the highest, based on the amount of lather components (creamy, foamy, bubbly; which I did not define in advance) and the total amount of lather. After watching a few soap lovers test soap in the past, I decided to keep it simple and did not give explicit directions on how to do the testing. I also asked for information on water hardness (soft, softened, hard) and for any comments on the soap. I asked the soap lovers to let me know which soap(s) they liked the best. The soap makers also voluntarily shared their preferences. A couple of the soap makers went over and above the call of duty by varying the way the soap was physically manipulated during testing, looking at how the lather changed over time of use (i.e. a few seconds to 20 seconds) and by comparing lather at the sink versus in the shower. My partner and I also tested the soap repeatedly over the last few months, but I excluded our results from the analyses to avoid any bias.
By mid-December, 13 testers had returned results, including 9 “soap lovers” and 4 “soap makers.” The testing period spanned from mid-October to mid-December.
Lather results - The most obvious feature in the results is high variability among testers for most lather attributes regardless of the recipe. Individual testers had preferences (see below) but compelling trends in performance across lather components or total lather amount were lacking due to high variability among testers. I used box and whisker plots (Excel) to summarize the lathering results by recipe:
The bubbly attribute is possibly the most interesting, with the palm & shea soap at the low end and the soy wax & cocoa butter and cocoa butter & shea soaps holding their own. A few testers that liked the latter two soaps specifically commented on how bubbly they were. For the record, I didn’t bother to make graphs of the scoring for lather across time or by water type (hard, softened, soft) because I didn’t notice any trends.
Preference results* -Eleven Nine testers provided 1st and 2nd favorite soaps and two four additional testers provided a first preference. Eight of 13 testers (61%) ranked the cocoa butter + shea soap in the top two (4 as first, 3 as second, 1 as tied). The lard and soy wax + cocoa butter soaps were next, with lard getting four (4) 1st place votes, but no and one (1) 2nd place vote and soy wax + cocoa butter getting two (2) 1st place votes, two (2) 2nd place votes, and one (1) vote as tied for top two. Tallow had two (2) 1st place votes and the palm + shea soap came in last with two (2) 2nd place votes. Testers generally had nice things to say about the soaps (lovely, awesome, ”love the soft, creamy lather”). Despite the low cleansing number, one tester thought some of the soaps left their hands feeling squeaky clean.
What’s the best way to test soap? An email exchange with another maker after they sent me their results led us to realize just how much the physical manipulation of soap during use affects the amount and quality of lather produced. For my soaps, we both found that rolling the soap in one or two hands makes bigger bubbles compared with rubbing the soap between palms. Perhaps this is due to more air being introduced when a soap is rolled. Without adding more water, both methods produce creamier lather as time goes on. When I test in the shower, the soap is wetter and so am I. Then I started noticing that I tend to use the rubbing method when I’m testing small bars of soap at the sink, but in the shower I roll bigger bars using two hands. When I was watching my partner lather up, I noticed that her rubbing method produced creamy results in 5-10 seconds, while my rubbing produced larger bubbles and denser “foamy” bubbles over the same amount of time for the same soap. A couple of testing runs I did with my eyes closed convinced me that my initial assessment of a soap is heavily influenced by seeing how it lathers. I’ve also tried testing soap with gloves on, which robs me of the sensation the soap produces in my hands. Testing soap qualities is full of complexities!
ETA: a few other variables that I discussed with soap makers during lather testing were: effects of size and shape of bar (surface area effects?), changes in lathering after a new bar is used a few times and effects of water temperature (warm water dissolves soap faster than cold water)
Final notes! The fatty acid profile I’m using for GW 415 is the “best fit” profile I calculated a couple of years ago based on the available data from the manufacturer. I guess it could be off slightly, but we’ll never know unless someone else decides to take a deep dive into the numbers. I added the avocado oil to raise the palmitic without having to make the cocoa butter percentage cost prohibitive. I briefly considered trying to tease out the unsaponifiable component of the recipes, but gave up on that idea pretty quickly because the data available online vary tremendously. At the least, unsaponifiables and “hidden fatty acids” that are not shown in the c@lculators add unknowns for those who want to formulate on the basis of fatty acid profiles.
*argh… this section didn’t seem quite right to me. I double checked the testing sheets and corrected the numbers. (9 testers x 2 votes = 18, 4 testers x 1 vote = 4, 18 + 4 = 22 votes total). I also missed a 2nd place vote for lard.
All recipes have the following properties in the SMF c@lculator:
Bubbly 17
Cleansing 13
Conditioning 52-53
Hardness 41-42
Longevity 29
Creamy Lather 33-34
And this fatty acid profile:
Lauric + Myristic 13
Palmitic + Stearic 29 (all palmitic dominant, but ratio varies among recipes from p:s 1.1 to 2.2)
Ricinoleic 5
Oleic 40-42
Linoleic + Linolenic 8-9
The palmitic and stearic-rich fats or fat combinations and palmitic:stearic ratios:
palm (no stir) + shea (refined); p:s = 2.2
lard (Armour brand); p:s = 2.2
tallow (Soaper’s Choice); p:s = 1.6
GW 415 soy wax + cocoa butter (unrefined); p:s = 1.2
cocoa butter (unrefined) + shea (refined); p:s = 1.1
Every recipe was made with aloe juice as a partial water replacement, sodium citrate as a chelator, Nurture’s 8th and Ocean FO and 2% superfat. The lye was food grade from Essential Depot. The soaps were color coded by adding different color swirls. (ETA: the soaps were made 8-11 August 2021; the testers identified the soaps by color; all testers knew there were five base fats/combos and the makers were given the FA profile and soap properties)
I sent the soap to 16 testers, including 10 “soap lovers” and 6 “soap makers.” Each tester was asked to score the soaps from 1-10, with 10 being the highest, based on the amount of lather components (creamy, foamy, bubbly; which I did not define in advance) and the total amount of lather. After watching a few soap lovers test soap in the past, I decided to keep it simple and did not give explicit directions on how to do the testing. I also asked for information on water hardness (soft, softened, hard) and for any comments on the soap. I asked the soap lovers to let me know which soap(s) they liked the best. The soap makers also voluntarily shared their preferences. A couple of the soap makers went over and above the call of duty by varying the way the soap was physically manipulated during testing, looking at how the lather changed over time of use (i.e. a few seconds to 20 seconds) and by comparing lather at the sink versus in the shower. My partner and I also tested the soap repeatedly over the last few months, but I excluded our results from the analyses to avoid any bias.
By mid-December, 13 testers had returned results, including 9 “soap lovers” and 4 “soap makers.” The testing period spanned from mid-October to mid-December.
Lather results - The most obvious feature in the results is high variability among testers for most lather attributes regardless of the recipe. Individual testers had preferences (see below) but compelling trends in performance across lather components or total lather amount were lacking due to high variability among testers. I used box and whisker plots (Excel) to summarize the lathering results by recipe:
The bubbly attribute is possibly the most interesting, with the palm & shea soap at the low end and the soy wax & cocoa butter and cocoa butter & shea soaps holding their own. A few testers that liked the latter two soaps specifically commented on how bubbly they were. For the record, I didn’t bother to make graphs of the scoring for lather across time or by water type (hard, softened, soft) because I didn’t notice any trends.
Preference results* -
What’s the best way to test soap? An email exchange with another maker after they sent me their results led us to realize just how much the physical manipulation of soap during use affects the amount and quality of lather produced. For my soaps, we both found that rolling the soap in one or two hands makes bigger bubbles compared with rubbing the soap between palms. Perhaps this is due to more air being introduced when a soap is rolled. Without adding more water, both methods produce creamier lather as time goes on. When I test in the shower, the soap is wetter and so am I. Then I started noticing that I tend to use the rubbing method when I’m testing small bars of soap at the sink, but in the shower I roll bigger bars using two hands. When I was watching my partner lather up, I noticed that her rubbing method produced creamy results in 5-10 seconds, while my rubbing produced larger bubbles and denser “foamy” bubbles over the same amount of time for the same soap. A couple of testing runs I did with my eyes closed convinced me that my initial assessment of a soap is heavily influenced by seeing how it lathers. I’ve also tried testing soap with gloves on, which robs me of the sensation the soap produces in my hands. Testing soap qualities is full of complexities!
ETA: a few other variables that I discussed with soap makers during lather testing were: effects of size and shape of bar (surface area effects?), changes in lathering after a new bar is used a few times and effects of water temperature (warm water dissolves soap faster than cold water)
Final notes! The fatty acid profile I’m using for GW 415 is the “best fit” profile I calculated a couple of years ago based on the available data from the manufacturer. I guess it could be off slightly, but we’ll never know unless someone else decides to take a deep dive into the numbers. I added the avocado oil to raise the palmitic without having to make the cocoa butter percentage cost prohibitive. I briefly considered trying to tease out the unsaponifiable component of the recipes, but gave up on that idea pretty quickly because the data available online vary tremendously. At the least, unsaponifiables and “hidden fatty acids” that are not shown in the c@lculators add unknowns for those who want to formulate on the basis of fatty acid profiles.
*argh… this section didn’t seem quite right to me. I double checked the testing sheets and corrected the numbers. (9 testers x 2 votes = 18, 4 testers x 1 vote = 4, 18 + 4 = 22 votes total). I also missed a 2nd place vote for lard.
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. The bars are: castile (bar 1), “very, very different soap” (bar 2, starts 2:57), tallow (bar 3, starts 4:20) and shampoo bars (bar 4, starts 5:28; bar 5, starts 6:30). Despite the shift in technique from rolling to rubbing, it looks promising.
(or when you have overslept the punchline).
