I really appreciate the photos. and can’t wait to see the finished product. The finished product looks terrific. Great job on the piping!
Making sugar scrubs from soap shreds
- Thread starter AliOop
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Thanks! LOL - we were typing at the same time, @Mobjack Bay 
I would have used plastic jars if I had them, so I’ll have to warn my friends and family to scoop some into a little plastic medicine cup to take in the shower - no glass jars in the shower!
I would have used plastic jars if I had them, so I’ll have to warn my friends and family to scoop some into a little plastic medicine cup to take in the shower - no glass jars in the shower!
@dmcgee5034 I’m one of those people that loves the picture-based instructions from Ikea 
First off, @AliOop thank you so much for sharing you soap shred sugar scrub knowledge and tips with us. I have tried to watch the videos, but would not have gotten to the point of taking on this project without your digested guidelines.
I finally made a nice batch of foot scrub. Despite the very clear recipe guidelines, I just realized that I deviated significantly from the suggested percentages. This is why I am not a chemist
I used:
200 g of relatively fresh soap shreds from a would be galaxy soap that accelerated a bit too much. The black is AC and it has a bit more superfat than usual for me - probably 5%
200 g of distilled water (100% shred weight)
150 g of glycerin (75% shred weight)
40 g of stearic acid (oops! I used 20% of shred weight rather than 20% of total batch weight) I used a lot less stearic acid than intended. If the TBW is based on the soap shreds, water and glycerin (550 g), I should have used 110 g of stearic acid. Perhaps the relatively high palmitic and stearic (30%) in my soap shreds saved me…
20 g of almond oil (oops! Again I used 20% of shred weight rather than 20% of total batch weight) If the TBW is based on the soap shreds, water and glycerin (550 g), I should have used 55 g of oil. This is a foot scrub, so less oily is just fine.
I also added some Klein Blue mica, likely 1/2 - 1 tsp, but I didn’t record the amount.
This gave me 610 g final batch weight before additives. I then added 2% fine/very fine pumice (12 g) and 1% ground apricot seeds (6 g), 0.5% preservative and 2% essential oils (peppermint and lavandin). The mixture was less like Play-Doh and more like Silly Putty (do they still make that stuff?)
It got worse overnight The Silly Putty stage, before and after additives (+whipping)
This morning I decided to add 75% sugar (based on 610 g batch weight before sugar). I tried 100% in a small portion, but 75% yielded a good texture and seemed to make a nicer lather compared with 100%.
I’m including a close up of the scrub because even though 1% ground apricot seed doesn’t sound like a lot, I think it’s just right. The pumice is fine and not as obvious as the sugar, but I can tell it’s there. I may go up to 2% pumice the next time.
The mixture was the perfect consistency for piping. Beginner’s luck! I never ordered plastic jars, so glass it is, with a wooden scooper spoon and instructions to keep the glass jar out of the shower.
ETA: One question I have is about how this will hold up over time. I assume the added stearic acts mostly as an emulsifier, but possibly also as a thickener? I wouldn’t want the scrub base to be any thicker/stiffer, but I will be sad if it splits.
I’m sorry that I never saw this until today. You can read about salting out soap at the Soapy Stuff website, here.
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This looks amazing! Mine hasn't separated at all, but I did use a bit more stearic than your final recipe. Please let us know how it holds up!
I do have a whole bunch of the base left from my initial experiment. You know, the one that resulting in filling a whole turkey roaster with shreds.
What was I thinking?? 
My next plan was to fiddle around with making the base into a shave soap, but I may have to detour into a charcoal-pumice-sugar scrub like yours.
I do have a whole bunch of the base left from my initial experiment. You know, the one that resulting in filling a whole turkey roaster with shreds.
What was I thinking?? My next plan was to fiddle around with making the base into a shave soap, but I may have to detour into a charcoal-pumice-sugar scrub like yours.
Nice job, @Mobjack Bay!
Mine still looks good and hasn’t separated, but it doesn’t lather as much as I’d like. I’m calling it a Cleansing Body Polish
Mine still looks good and hasn’t separated, but it doesn’t lather as much as I’d like. I’m calling it a Cleansing Body Polish
@dmcgee5034 I have added SLSa or SCI to mine to bump up the lather a bit, and I do like the results better. I don't remember the amounts, but it wasn't much.
Quick update - I didn’t like the texture of my batch at the 24 hour mark. It was back to feeling a bit waxy/smooth/slick, which I’m calling Silly Putty for lack of a better description. I went back to the drawing board. Google found a section of a Soap & Clay video where they link waxy texture to high stearic content, so I’m glad I didn’t add more stearic then I did. Plus, I suspect that my soap shreds have more palmitic and stearic (and less coconut oil) than the soap shreds most are using when they try this method. After pondering this for a bit, I think one possible fix in the future would be to add some CO soap shreds to my mix to lighten it up a bit. Since I couldn’t think of a way to correct the fat profile in the base that already has the sugar added, I started reading other sugar scrub recipes online and decided to try adding more sugar to my batch after finding many recipes with sugar at > 100%. The addition of 66% sugar to an aliquot of my batch that originally had 75% sugar added (based on original weight of shreds, glycerin and water), along with a bit more pumice and a wee bit of MCT and water yielded a much nicer texture. This morning it’s looking like I could have left out the water (see below), but the mixture was nicely pipe-able yesterday, is the perfect consistency for the silicone tube and does not feel at all waxy. I will update when I do the math to figure out the exact percentages in the final mix.
Given my uncertainty about the stability of my soap shred foot scrub, I decided to take just the tester with me to my gathering. I stuck it in an outdoor shower for general use, which means it was out in the heat and got some direct sun for a few days. Reviews were positive! As of this morning, the consistency had not changed in any noticeable way from what I posted above, and most importantly (to me), it did not revert to Silly Putty.
ETA: Based on some fast calculations, the sugar I added in the adjustment step brought the total sugar up to 200% of the combined wt of shreds, water, glycerin, stearic acid and oil (BW1) and the total pumice added was 14% of BW1. Interestingly, after being at cooler temps since this morning, the scrub is a bit stiffer than it was this morning, but still not waxy feeling. It makes just enough lather to have a nice feel in use. Given the circuitous path I took, I’m optimistic that I have a reasonable dup of the product I was aiming for.
ETA: Based on some fast calculations, the sugar I added in the adjustment step brought the total sugar up to 200% of the combined wt of shreds, water, glycerin, stearic acid and oil (BW1) and the total pumice added was 14% of BW1. Interestingly, after being at cooler temps since this morning, the scrub is a bit stiffer than it was this morning, but still not waxy feeling. It makes just enough lather to have a nice feel in use. Given the circuitous path I took, I’m optimistic that I have a reasonable dup of the product I was aiming for.
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@Mobjack Bay thank you for sharing your recipe and testing notes! A final recipe summary, if you are so inclined, would be amazing.
Now that I’m back from my trip, I was really anxious to get a rough idea of where I ended up, but I’m definitely going to need to check the calculations before I share them. If only the aliquot I adjusted had been 100 g instead of 75 g. What was I thinking…@Mobjack Bay thank you for sharing your recipe and testing notes! A final recipe summary, if you are so inclined, would be amazing.
My best estimate of the final percentages I used in the foot scrub are in the table below along with the percentages for the initial batch and adjusted percentages I want to try for a small next batch. As a reminder, the initial percentages resulted in a scrub that was still a bit waxy after 24 hrs. I used the modified scrub in the shower this morning and like it, but I think it can handle a wee bit more oil and exfoliants. The current version rinsed clean with no oily feeling left on the skin and my skin also didn't feel tight or dry. That was okay, but I want to see if more liquid oil, like MCT, will loosen the scrub a little. For the next attempt, I dropped the sugar a bit to compensate for increasing the pumice and ground apricot seeds and also rounded the recipe percentages a bit to make them easier to remember in use.
With so much sugar in the mix, the preservative level in the current batch is only 0.15%. Should the amount of preservative be calculated based on the weight before adding the sugar, or the final batch weight after the sugar is added?
As a reminder, I used relatively fresh tallow & lard-based soap (palmitic & stearic = 30%, approx 5% SF; 20% CO) that was made using 40% lye concentration. I don't know how much difference the initial fatty acid composition of the soap makes when this much sugar is involved, but prior to adding the sugar my initial batch had a bit of a Silly Putty/waxy texture and a hint of that texture at the 24 hr mark (see my previous posts).
With so much sugar in the mix, the preservative level in the current batch is only 0.15%. Should the amount of preservative be calculated based on the weight before adding the sugar, or the final batch weight after the sugar is added?
As a reminder, I used relatively fresh tallow & lard-based soap (palmitic & stearic = 30%, approx 5% SF; 20% CO) that was made using 40% lye concentration. I don't know how much difference the initial fatty acid composition of the soap makes when this much sugar is involved, but prior to adding the sugar my initial batch had a bit of a Silly Putty/waxy texture and a hint of that texture at the 24 hr mark (see my previous posts).
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Preservatives are always based on the total. Remember we cannot see bacteria until it’s overwhelming the product.
My understanding is that since sugar is self-preserving, that for products with a high percentage of sugar (like these scrubs), that you base the preservative on batch weight minus sugar weight.
By itself, yes, and so is honey. But adding sugar to a product is a completely different story, it’s adding bug food.
My understanding is based on the recommendation of at least one professional formulator (Susan Barclay of SwiftcraftyMonkey) who calculates the preservative on the pre-sugar weight if sugar is at least 50% or more of the total product weight. She has some interesting reading on the subject to explain the science behind this, i.e., the “water activity” of sugar. She also cautions that she is only confident that this works if one isn’t adding other strong bug food like ground botanicals, etc.
Another professional formulator, Sandra LaBossiere of DIY Bath & Body, also bases her preservative on the pre-sugar amount, but doesn’t explain why. I assume she is relying on the same science shared by Susan.
Another professional formulator, Sandra LaBossiere of DIY Bath & Body, also bases her preservative on the pre-sugar amount, but doesn’t explain why. I assume she is relying on the same science shared by Susan.
I have several of Susan’s ebooks as we as being a patreon. I still believe the amount of preservative is based on the total amount of product. I also have a masters degree in chemistry.
