Monday, May 30, 2016

One ingredient, five products: Stearic acid - foot scrub bars

With summer sandal season looming on the horizon in the northern hemisphere, a lot of attention is paid to our feet. Check out this recipe for a foot scrub bar containing stearic acid. (Which can be paired nicely with the thicker foot cream with stearic acid we made last week...)

A lot of the ingredients are the same as they were for the body scrub on Friday, but we're using them in slightly different amounts and adding a few others to make the product more moisturizing for our lovely feet! (Take a peek at that post if the ingredient that interests you isn't explained in detail here.)

We've upped the amount of stearic acid to make this bar hard and resilent when used with our feet. It'll still be lovely and moisturizing, but we want it to be able to scrub a lot harder than the body scrub bar without breaking. I'm reducing the hard butter to make up for that change.

As an aside, I wouldn't use kokum in this bar as it will be very very hard and won't glide over your feet well. I include it as an option as some people might like that feeling, but I certainly didn't. I definitely suggest cocoa or mango butter! 

I'm adding wax to this bar to make it stay on our feet longer. I have found that 4% beeswax with 10% stearic acid can be a bit draggy, but it definitely makes the moisturizing oils and butters feel like they're on my feet longer, so I include them. If you really hate the feeling of wax, leave it out and include more oil. (If you want to use a different wax, please see the notes beside the beeswax entry.)

I'm using shea, coconut, or babassu oil for my slightly greasier, less stiff oils at 20%. You could use all cocoa, kokum or mango butter here and have a really hard bar, or include the shea or coconut oil and make it a slightly softer bar. I really don't suggest using a harder butter for that 20% as the bar will be really draggy and unpleasant on your skin.

As an aside, I really didn't notice a difference in skin feel when I used babassu in these bars, so I suggest leaving it out and using the less expensive coconut or shea butter instead.

When it comes to oils, I recommend thick, greasy feeling ones to increase the feeling of moisturization. You can choose any ones you like, but this is where I like to use olive oil for all those moisturizing and softening fatty acids.

We're using pumice and baking soda as the scrubbies in this bar. You can use any physical exfoliants you wish, but this is my favourite combination. I use it at 100% of the bar, so I make 100 grams of the bar base, then add 80 grams of pumice and 20 grams of baking soda, mix well, and glop into the molds.

46.5% cocoa, mango, or kokum butter
20% shea, coconut, or babassu oil
12% oils - heavier oils like avocado, castor, or olive oil are great here
10% stearic acid
5% emulsifier of some sort - Incroquat BTMS-50 or 25, Polawax, e-wax, etc.
4% beeswax or soy wax or 2% candellia or carnuaba wax
1% Phenonip or other heat tolerant preservative

1% fragrance or essential oil (I recommend peppermint) or 3% menthol crystals (not heat sensitive)
0.5% Vitamin E (if you are using oils with less than 6 months' shelf life)

(This recipe doesn't add up to 100% if you change the wax.)

Add up to 100% pumice (or 80% pumice, 20% baking soda)

Melt everything except the fragrance/essential oil and Vitamin E in a heat proof container in a double boiler until all the ingredients are well melted. Remove from the heat and add the fragrance/essential oil and Vitamin E (optional), and mix well. (Maybe 20 seconds.) Then add your exfoliant and mix well. Then pour into a mold and put in the fridge or freezer until set. Let sit for 24 hours before using, or it can fall apart. It can take up to 24 hours for stearic acid to completely harden.

What do I think of this recipe? I do love a foot scrub bar. I always make mine with pumice and baking soda, and I find this offers a nice scrubby feeling that doesn't feel too scrubby. I used menthol in this last batch, and it definitely adds a slight tingle at 3%. I used cocoa, shea, and olive oil in this version and I thought it was very moisturizing without making my feet feel slippery when I put shoes on about half an hour later.

Can you colour these bars? Yes, you can. You have to use an oil soluble colour, like those powdered ones you could find for chocolate making, not a water soluble one like food colouring or our LabColours. I've made them green before, but I stopped because I kinda like the colour it is now.

Other posts in this series:
One ingredient, five products: Stearic acid
One ingredient, five products: Stearic acid - a hand lotion
One ingredient, five products: Stearic acid - foot cream
One ingredient, five products: Stearic acid - body scrub bars

Join me tomorrow as we make shampoo bars with stearic acid!


Елена Литвин said...

Good day, Susan!

First of all, I`d like to say that I`m incredibly happy to find your blog through so much information on the internet with untested, useless and often ridiculous recipes. It is a great honor to me to be one of your biggest fans! I`ve been reading your posts for a while right now and have made a lot of products using your recipes and recommendations. Many of them I really like and think them to be the top of awesomeness and some of them made me want to reformulate a little. Being a cold process soap maker, I often regret that your blog is not about soap, your posts about hair chemistry and why CP soap is not good for hair blew my brain (if it can be sad so). With all those soap makers who insist on washing hair with CP soap I never understood why my hair felt so bad after it... Now I know they are WRONG, I thank you for that!

Anyway, I have some questions on different recipes, I know they are probably out of topic, I apologize for them, but I thought I would better write all in one message for now. May be some of them if not all are already answered and I did not do good search enough, I`m really sorry for that and ask you to guide me to the right direction on them. Thank you in advance!

1. My whipped butter (80% shea butter, 19% macadamia nut oil, 1% Vit E oil) was a disaster and complete frustration, after I whipped it, it solidified immediately (may be after 2-4 minutes) and when I wanted it to pipe it became crumbly and unmanageable. As for the process – first I heated it to incorporate everything well, then I put it in the freezer. I`ve never done this kind of butters before and maybe there is something I don`t understand about the process. Please help.

2. Second question will be about acids and toners (and more). I used one of your recipes to make a toner for my dry (rosacea prone type) skin. The recipe called for 2.5% sodium lactate and 2% niacinamide. When I tested the pH it was 2.1 and my face was on fire to say the least. Actually I first tried it on my face and then I checked the pH, I KNOW I had to do the opposite and it`s all my fault.... not blaming anyone!!! I just did not expect that from a toner with a tested recipe, sorry. I thought if you combine acids in “MAXED OUT TONER FOR DRY SKIN” from I can do that too. I know you ALWAYS say “KNOW YOUR INGREDIENTS!!!” but after that I started to think about 2 things: first, how to balance the pH when you combine acids, and second how to know for sure whether my honeyquat, germal plus and proteins are actually them (I cannot really rely on suppliers in my country as there are some that dilute ingredients with water, that I know!).

3. Have you ever thought about bad breath sprays? I have sometimes this problem but essential oils are not an option for me, may be there have to be some medical ingredients?

4. Solid scrub bars were thought to be a great stuff but when I tried one, it was toooooo GREASY and WAXY for my tastes, I could not even washed it off at first. Maybe it`s not my product but maybe there is a way to make more washable by adding more BTMS or another e-wax. What do you think?

5. And the last but the most important question to me. I make solid shampoo and conditioning bars a lot and still have some problems with adding the cool down phases. As far as I know CDP has to be added when the mixture comes to 45 degrees Celsius, but the mixtures of shampoo and conditioning bars solidify by that time and it is hard to pour it nicely in a mold (actually it`s impossible to pour, I use a spatula and my hands (with gloves) to put it a mold – and it pisses me off to tell the truth, because it`s not pretty when it`s done this way) – is there another way to make a pretty bar? Probably your answer would be – not to use silicones and panthenol, and pour it while they are hot, right?

Any answer would be appreciated! Thank you, Susan for your time, energy and experience!

Елена Литвин said...

Oh, and another thing! Almost forgot!

I`ve been trying to find a recipe for a bath bomb frosting that does not contain any cream of tartar or meringue powder, because I cannot find them locally, I saw your recipe with surfactants, but to my opinion there are too much of them, can we reformulate the recipe a little?

Say, using a little foam booster (SCI or SLSa - 10-15%, not more), powdered sugar, kaolin clay, corn starch, salt or baking soda in powders and butters&PS 80 (as a whipped base) and some DLS&Cocobetaine, glycerin &vodka in liquids (our country does not even know what witch hazel is, and of course I cannot find it anywhere, that is why I suppose vodka will do the job as well as Kathy said here – sorry for the link, it`s not an advertisement, really, please remove it when you see what I mean).

As far as I understand there have to be a lot of experimenting so the recipe could hold the shape and solidified not very fast and not very slowly, and a finished product could melt easily in warm water as fast as a bath bomb base itself.

If you have some ideas on supposed recipe rates, please answer. Thank you again!

Danuta Kilar said...

Susan the foot scrub with pumice is such a brilliant idea. Thank you for that. I am going to make one for myself. Thank you so much for this post:))

Yekatherina Bruner said...

Hello Susan, thank you for all your invaluable knowledge and help you give us through this blog. It has made me a better formulator. My question to you today is....
Back in December 29, 2011 you posted about the Solid Foot Pumice Bars with a recipe that included sodium lactate. The one on this particular post does not include it and it adds more of the stearic acid. Is there a particular reason why you took out the sodium lactate (as in safety reasons) or does it have to do more with showcasing the stearic acid in this particular post.

Thank you so much!

Susan Barclay-Nichols said...

Hi Yekatherina! The short answer is that I wanted to showcase stearic acid in this recipe. There are no safety concerns about sodium lactate, except that we don't want to go over 3% in a product as it can be sun sensitizing. I don't generally worry about that in a foot product, though.

I'll have to get to the other comments on the weekend when I have more time.

cindy ladnier said...

Are these bars meant to be used in the tub and then washed off or do you use them out of the tub and then just brush it off? I've never used one before but it sounds like a great product that I would love to try as soon as possible since it's sandals weather. :) I love your blog so much and will participate in the Patreon page as well. Thank you for all you do and share.

Susan Barclay-Nichols said...

Hi Eneka. I only have time for a quick answer right now, but I wanted to address your thoughts on the toner. Almost all the ingredients are slightly acidic as our products should be, but nothing is a serious acid like an AHA that will drop the pH that far. Niacinamide has a pH of around 6 to 7, and sodium lactate is a base with a pH of 7.5 to 8-something. There's nothing in the recipe as I have written it that would bring a pH down that low. There's nothing I've ever written that should be that low! This recipe as written is around 5.5-ish, if I recall correctly.

There's something really wrong here, and I would ask you to write your complete recipe with percentages and exact ingredients (prefer INCI names, not generic ones, if possible) and post it in that toner recipe post - not here, please - and we can troubleshoot it. I can't help unless I know exactly what you've done with the product, so please write as soon as you can.

Елена Литвин said...

Hello Suzan!
Sorry for late reply, I have checked all of my ingredients and found that my sodium lactate was actually lactic acid! I wrote to the seller and apparently they found out that there must have been a mistake in labels. I remade my formulations and everything was ok!

I`m still worried about adding the cool dowm phase to solid conitioner bars and shampoo bars, as I wrote earlier. PLEASE HELP.....

..... I make solid shampoo and conditioning bars a lot and still have some problems with adding the cool down phases. As far as I know CDP has to be added when the mixture comes to 45 degrees Celsius, but the mixtures of shampoo and conditioning bars solidify by that time and it is hard to pour it nicely in a mold (actually it`s impossible to pour, I use a spatula and my hands (with gloves) to put it a mold – and it pisses me off to tell the truth, because it`s not pretty when it`s done this way) – is there another way to make a pretty bar? Probably your answer would be – not to use silicones and panthenol, and pour it while they are hot, right?

Thank you in advance!


Susan Barclay-Nichols said...

Hi Elena. What's CDP?

Елена Литвин said...

Hello Suzan!
CDP - Cool Down Phase.

Susan Barclay-Nichols said...

Hi Elena! I add the cool down phase when the product is melted, so I keep an eye on the temperature. You can get things melted at low temperatures to add panthenol and silicones.

Is there a chance you could pose this question on a more relevant post, like one on shampoo bars or conditioner bars? Actually, as a thought, I feel like I've address this issue before on those posts, so it seems like a great idea to find one of those posts and ask it again there!

michele eno said...

Hi Susan, With summer just around the corner ( wishful thinking !), I'd like to try these solid pumice scrub bars. What mold do you use ? Is there a better size, or just personal preference> There seems to be a lot to choose from out there.

michele eno said...

Hi Susan,
With summer just around the corner ( wishful thinking) I'd like to try these solid pumice foot bars. What mold do you use? Is there a better size, or is it simply personal preference? There seems to be a lot available. Also, are they a "one use" item, or can you dry them out and re-use? Would they need to be wrapped afterwards? Having never used one, I'm a little unsure!Thanks in advance; I can't wait to try it.