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Basic or Bedazzled?

I’m so Fancy ….

Silver Fox Shaving Soap is elegant in it’s simplicity.  It contains only that which is necessary to make soap, with a nod towards earthly pleasures via the fragrance.  But that’s it.  It is an open wheeled car in a world of coupes.  Can we take it to the next level and make it look fancy?  We can.  Can we improve it even more?  Maybe.  In this article I will explore color and consistency, along with a discussion of performance vs aesthetics.

The Players

There are three new components I will be using in this batch:

  • Sodium Lactate (SL) – This is the sodium salt of lactic acid.  This compound acts as a humectant/moisturizer in lotions.  In soaps, it is said to change the consistency of batter or hot soaps, as well as harden the cooled/cured soap.
  • Tetrasodium EDTA (EDTA) – Ethylenediaminetetraacetic acid.  How’s that for a mouthful?  Ethylenediaminetetraacetic acidis a chelating agent; it binds metal ions and removes them from suspension.
  • Titanium Dioxide (TiO2) also called Ti or Titanium White – This is a naturally occurring metal oxide used to opacify (make less transparent) colored products , or to create a white tint in products.

Sodium Lactate

Sodium Lactate can be purchased from many soap and cosmetic-related vendors.  It is available as a white powder, but is most commonly purchased as a slightly viscous pale yellow liquid.  If one researches usage rates in various books, articles, and websites, ranges from 0.5% to 4% are given.  Many recipes out there call for a teaspoon per pound of oil (PPO.)   I abhor that sort of measurement.  Sure it’s easy for the kitchen soap queen to do, but it tells us nothing quantitative.  “Teaspoon” as described on the Interwebz could be that spoon in your drawer, or an incredibly accurate measure of 4.92892 ml/tsp.  According to the U.S. Library of Medicine 1 tsp is 5 ml.  Sodium Lactate’s density is 1.33 g/ml as a powered.  Generally the syrup is a 60% concentration in water so that liquid we use would be 1.198 g/ml.  If you take that teaspoon (5 ml) and multiply that by the mass (1.198 g/ml) you end up with 5.99 g per tsp.  A pound is 454 g so 5.99 g per 454 g is 1.3%; that’s the empirical usage rate of 1 tsp PPO converted into real numbers.  Max usage in that incredibly inaccurate system of something PPO is  is about 3.6 tsp / PPO.

I rather arbitrarily chose an amount that ended up being 3.9% of the oil weight.   This amount was added to the lye water.  It was still quite warm, let’s color it 130°F when I added the SL.  For fun, my 3.9% is  3.5 tsp / PPO.

SLRate

The soap was much easier to mix in the pot, going from the mashed potatoes of a hot processed batch to more of a Cream of Wheat consistency.  It was definitely easier to deal with, easier to stir, easier to keep in the pot, and much easier to mix in the oils and fragrance at the end.  When it came time to portion this into my tins, it was vanilla pudding consistency and was more of a blop and shake endeavor than the smear process I used with the non SL soap.   Very technical terms we are using here.   Just imagine trying to make a nice smooth top out of potatoes, versus pudding.

When the soap cooled it was much harder than normal, my fingernail test tells me it is every bit as hard as a bar of Ivory Soap for instance.  This would make pucks of soap created with 100% Potassium Hydroxide a very do-able thing.  A measure of “too much” SL in bar soap is when the soap crumbles when cut.  Since I am pouring this into tins I won’t be cutting it.

Since this ended up being on the high end of SL usage I decided to dial it back some to about 3%.  While the hardness was there when done the soap was back to what I’ll call soft mashed potatoes.  Better than none but a lot worse to work with than the 3.9% so barring any negative use testing, 3.9% will be my number.

I also have my suspicions about the use of sodium salts in shaving soap.  When someone gives me a sample of their shaving soap made in part with Sodium Hydroxide (to create a harder puck,) I very often feel a slight sensation of dragging/grittiness.   I can’t describe it better than that except to say it’s not as slick as snot (which is a good thing in this analogy.)  Since soap is a salt created from a fatty acid, and Sodium Lactate is another salt so created, will use of Sodium Lactate create this characteristic?  It’s an interesting thought experiment.  If it is sodium salts which create this effect, then use of very low percentages may allow the beneficial effect of the addition without realizing any of the detrimental impact.

Tetrasodium EDTA

This mouthful of an ingredient is used to help combat minerals in the water.   Calcium or Magnesium in the water will combine with the sodium or potassium ion preferentially and cause difficulty with lathering in extreme cases.  In nearly all cases there will be some soap scum generated which is the calcium or magnesium salt of your oils.  EDTA binds these minerals in a process known as chelation, which removes them from being able to react and cause these negative effects.  EDTA is available as Trisodium EDTA or Tertasodium EDTA.  The former is for neutral or acidic compounds, the latter is for alkaline.   Our soap is alkaline so we will use the Tetra-variety.

I calculated the EDTA addition at 0.5% of the total batch weight, which seems to be a common number for soapers.  It can be used up to 4% to combat the effects of hard water.

In closing on this chemical, it is deemed safe and anyone who tells you otherwise is a scare-monger.  Check the government testing here:

Final report on the safety assessment of EDTA, calcium disodium EDTA, diammonium EDTA, dipotassium EDTA, disodium EDTA, TEA-EDTA, tetrasodium EDTA, tripotassium EDTA, trisodium EDTA, HEDTA, and trisodium HEDTA.

In a nutshell:

“Based on the available data, the Cosmetic Ingredient Review Expert Panel found that these ingredients are safe as used in cosmetic formulations.”

Titanium Dioxide

Titanium Dioxide is an opacifier and a white coloring agent.  Used with other colors it can help make them pop.  Used alone it can make the soap less translucent and creamier looking.   It is non-reactive so unless you have to worry about how it plays with other colors (and we do not) there’s really no reason to worry too much about how much is used.  A typical addition for non-colored soap to help it look white is ~1%.  In this batch I calculated it at 0.5% of the weight of the oils.

Incidentally, this is the same pigment used in nearly anything that needs to be opacified or made white including foods, cosmetics, paints, even sunscreen.  Remember the white noses on the lifeguards?  Titanium dioxide at work.

The Results

Here’s a picture of this batch in the tin, versus the “classic” recipe cut into pucks.  You can really tell a difference.  The classic recipe was almost like vaseline in appearance, where the soap with SL and Ti are much creamier looking.

FullSizeRender (2)
Pucks

On the Sodium Lactate, so far I have not detected any difference in the lather qualities between soap with and without SL.  I did notice though that the soap loads a little bit slower, likely due to the hardness of the soap.  I’ll keep testing and report back if I find any changes.  In a worst-case scenario, I can create potassium lactate by reacting KOH with Lactic Acid.

Closing

This soap is for me and I will be using these three additions to my soaps from now on.   You need to make up your own mind on it for your soaps.  Hopefully I have included enough information to help you make your decision.

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A New Wrinkle

Oops

On The Soap Making Forum, a reader asked about an apparent inconsistency with regards to the stearic acid.  I made a point to say we want CAS 57-11-4 which is just stearic acid (within the limits of purity).  He pointed out that while the CAS was right, the MSDS said it was a mixture of:

  • Hexadecanoic Acid (CAS 57-10-3) 59.0%
  • Octadecanoic Acid (CAS 57-11-4) 40.0%
  • Tetradecanoic Acid (CAS 544-63-8) 1.0%

What is that alphabet soup you ask?  Good question.  Hexadecanoic Acid is Palmitic acid in International Union of Pure and Applied Chemistry (IUPAC) nomenclature.  Octadecanoic Acid with its CAS of 57-11-4 should look familiar; that’s Stearic acid.  Tetradecanoic Acid is Myristic acid.  So it turns out this is exactly the thing I told you we don’t want.

I emailed the customer service address for Lotioncrafter and the owner, Jenny Welch and I exchanged a few emails.  She shared with me, well, let me share exactly what she said:

“I consulted two cosmetic chemists that were well known and trusted in our industry and both recommended that I bring in Emersol 7036 Stearic Acid NF which was, and still is, the one most often used by cosmetic formulators in formulations calling for vegetable based stearic acid.”

She was very up front about everything, and I want to be clear the error is MINE because I did not read their MSDS; I stopped reading after seeing the CAS number I wanted.  She is coming at this from the point of view of someone making cosmetics and I have no doubt what she says is true.  To a person not saponifying the fatty acids this is just a matter of semantics and it makes no difference since to them this is stearic acid.  And, to be fair the manufacturer also lists the product as having CAS 57-11-4, but then follow up with the same ingredient list if you read into it more.  It’s confusing to me, maybe there’s a reason. Either way Jenny updated her website to reflect the three CAS numbers just because she thought it was the right thing to do.

Lotioncrafter came highly recommended to me and I can see why.  It is tough these days to do business online and still be responsive to people.  Just because you can order things now doesn’t mean people are waiting now to answer your questions.  Jenny was very prompt with her initial and follow-up emails though, surprisingly so.  In my book this simply solidifies the high praise with which she was recommended to me.

Incidentally, Emersol makes EMERSOL® 153 NF which is ~95% stearic acid (plus some impurities).  I asked Jenny if I purchased a whole bag if she could drop ship it.  As I feared, she buys only by the pallet and I don’t need a pallet of the stuff.  Buying in large quantities is how she keeps the cost down for what would likely be very expensive to us otherwise.  It looks like I will have to live with a different product from now on.  Shame on me for not being more thorough!

Now I have more questions.  You see, Palmitic acid has a lower molar mass than Stearic.  This means that there are more molecules of Palmitic acid per a given weight than Stearic.  For the really geeky folks:  The molar mass of Palmitic acid is 256.4241 g/mol where Stearic acid is 284.4772 g/mo.  For every molecule of a fatty acid we need one molecule of lye.  In our case that lye is KOH or Potassium Hydroxide.  The ratio of the two is the SAP value.  We can figure the SAP value of this new product if we know what the molar mass of the components are because it is the ratio of the weight of the lye molecules to the weight of the fatty acid molecules.  So, for each:

  • Lye (56.1056) / Palmitic Acid (256.4241) = 0.219
  • Lye (56.1056) / Stearic Acid (284.4772) = 0.197
  • Lye (56.1056) / Myristic Acid (228.3709) = 0.246

“Great” I hear you saying; “now what?”  We multiply those by the percentage of each in the product, and add them together to get our new SAP value.  Our values look like this:

  • 59% Palmitic @ 0.219 = 0.129
  • 40% Stearic @ 0.197 = 0.079
  • 1% Tetradecanoic @ 0.246 = 0.002

Add those and we get a new SAP value of 0.210 for our work.  See how relatively simple that is?  What does this mean for our soap?

Soapcalc has Stearic acid at a SAP of 0.198.  The new product I have has a SAP that’s ~6% higher.  The original recipe used Stearic acid at 45% so that’s an effective difference of ~2.7%.  Our superfat was calculated at 5% so it does raise the superfat from 5% to ~7.7%.  The difference is small.  We’ve also got a different fat makeup now; the difference in the fat profile is pretty simple.  The new formulation is +18% Palmitic and -18% Stearic compared to the original.

Both Palmitic and Stearic acid contribute dense stable lather and a harder soap to the mix.  To most soapers the two are interchangeable.  To settle it, I did what I said I was not going to do in the other article:  I re-formulated.  I made three small test batches:

  1. A test batch with my original (now dwindling) supply of straight Stearic Acid
  2. A test batch switched 1:1 with the Lotioncrafter product
  3. A test batch with lye adjustments made to take the different fats into account

The testing was randomized and I shaved three times with each one and recorded the results.  This was done to help even out the effect of the soap as it ages since it was used relatively soon after the cooking.

Results?

  • The first shave cycle had one sample just maybe being a tiny bit drying.   It was still a good shave and all had very similar lather otherwise.
  • The second shave cycle I thought maybe there was a difference but as I looked back at my notes I realize I was just kidding myself.
  • The third shave cycle was much like the second. Maybe, just maybe, one was a tiny bit drying.  All were good enough to put my name on them though.

When I peeled the tape off the labels, I discovered that in round one I did score batch #2 down just a tiny bit.  In round 2 the one I thought maybe was a tiny bit drying was the original (#1).  The difference was so slight that it could simply have been a difference in the humidity.  By cycle three the one I thought might be drying was again sample #2, the straight swap.

The winner was basically a tie, there was not enough difference to say one way or the other.  A better test would include more shaves, different people, all that mess.  Since I make this for me I see no reason not to use the Lotioncrafter product going forward.  If you do a test, do let me know what you think.

The old recipe was:

  • 45% Stearic Acid
  • 25% Coconut Oil
  • 20% Tallow
  • 5% Shea Butter
  • 5% Lanolin

The new one, adjusted for the Stearic Acid available to us, is below.  If you use SoapCalc you will notice that there is only “Styearic Acid” which aligns with the values for straight Stearic.  I did forward them a request to list the Stearic Acid NF, and they will whenever they do an update.  In the meantime you need to put in the three component fatty acids so the recipe is:

  • Stearic Acid NF; which would be represented like this in SoapCalc:
    • 26.55% Palmitic Acid
    • 18% Stearic Acid
    • 0.45% Myristic Acid
  • 25% Coconut Oil
  • 20% Tallow Beef
  • 5% Shea Butter
  • 5% Lanolin

Then, you will add together the weights for Stearic Acid, Palmitic Acid, and Myristic Acid and that total weight is what you will use for your Stearic Acid NF addition.  We go into this with the assumption that properly balanced; the Palmitic/Stearic/Myristic mixture will perform the same as the Stearic formula of the original recipe.  We therefore use the same percentage (45%) but now we split it up between the three components in Stearic Acid NF so that SoapCalc will figure the lye correctly.  If you compare the two recipes through SoapCalc the oil weights will be the same, but the lye is slightly different.  We had to balance for the different SAP value of the new product.