Sunday, May 19, 2013

Weekend Wonderings: Troubleshooting solid scrub bars!

In this post on solid scrub bars, Julia asks: I love this scrub bar, but so far I have always made it without sodium lacate. Which is fine until it reaches about 27˚C, it starts getting soft and mushy. So I want to add the sodium lactate. Problem I've run into: It is 60% Salt to 40% Water (advertised as bacteriostatic). So if use this in my anhydrous scrub bar, will it even mix since it is part water? And then it raises the question if I should use an additional preservative due to the water. I haven't been able to find any 'pure' sodium lacate, they all seem to be mixed with water. What are your thoughts?

Sodium lactate really is a big part of the hardening of this bar. You can find sodium lactate crystals - find them at Lotioncrafter, for example - but how would you dissolve it? It's water soluble, so you'll have to use a bit of water anyway. And if you're adding 3% sodium lactate, you're okay without a preservative because the liquid version will have enough preservative in it to preserve the water, plus it's bacteriostatic, so less than 5% will be fine in this product.

Having said this, I use Phenonip in my bars these days, which will be enough to preserve the entire product (use it at 1% of the non-sugar or salt part of the recipe). (I'm in the process of updating my bar recipe posts with this information, but I haven't found all of them!)

Can I make a suggestion that might seem like I'm being sarcastic? Have you considered storing them in the fridge or freezer? I put a lot of my stuff to freeze over the summer months to keep them fresher - like oils and butters - or from melting - especially coconut oil.

As for adding a water soluble thing to this recipe, you'll notice it contains an emulsifier as it's an emulsified scrub bar. So the e-wax or Incroquat BTMS-50 or Ritamulse SCG or other emulsifier you use will be able to handle a bit of water soluble stuff.

In this same post, Irish Molly writes: I just wanted to let you know I tried the scrub recipe. I did not have sodium lactate so I added the 3% to the 2% wax (I used bees wax) totaling in 5% bees wax and since you were using sodium lactate as a hardener I also used 60% cocoa butter and 10% mango butter. Everything else stayed the same. The resulting scrub was amazing!! It was not oily, had this amazing glide on my skin and left a powdery soft feeling after. My only question is that it never hardened. Did I do something wrong? I heated and held, the oils I used were 4% coffee infused Olive Oil, 4% coconut oil, and 4% Camellia Seed Oil. I added the silicones, E and EO when it cooled down to 45C. For the exfoliants I added 55% out of the recipes total weight which was 100 grams. 55 grams of exfoliants were used in the form of 15g coco powder, 20g Baking soda, 20g of finely ground coffee. Did I do something that would cause the bar not to harden? It never did - it was almost like a soft body butter consistency - amazing but not what I expected. I cannot find the error unless it was omitting the sodium lactate?

Thank you for sharing as much information as you can, along with your process. This really helps me figure out what's going on!

When you say it won't harden, there are four things to consider: The Incroquat CR or BTMS, the sodium lactate, the amount and type of exfoliants, and the temperature.

The emulsifier in this recipe - Incroquat CR, Incroquat BTMS, e-wax, Ritamulse SCG, and so on - will help harden the bar. I know it's not a lot, but it's enough to make a difference. The sodium lactate really is an important feature in the product. It is amazing what 3% can do in a bar to harden it! And I wonder about the amount and type of exfoliant. I tend to use about 100% salt or pumice/baking soda in mine, and I wonder if using less salt or sugar or fine crystal type exfoliants might be making a difference? And I wonder about putting them in the freezer to solidify. I put mine in the freezer, then store them in the fridge in the summer.

As an aside: They will melt and might try to fall apart when you've used them in the shower or bath. That's kinda the point!

I make a foot scrub bar that is pretty much the same recipe as the body bar, except I use stearic acid and pumice/baking soda in that one. It is a very very hard bar - too hard for my tastes thanks to the stearic acid!

Having said all of this, I'm still confused. If we took the ingredients without the scrubbies, it's pretty much a lotion bar, which will solidify nicely. (Sometimes I make up a batch without the exfoliants and store it so I can melt it down later when I'm ready for more bars!) I've used black cocoa butter in mine for years, which is much softer than cocoa butter, and I still have a solid bar. I'm really not sure what is happening in either situation, except for the lack of sodium lactate.

Here are a few ideas...
  • Make sure you are using the sodium lactate. If you can't, then up the wax to 5% and up the emulsifier to 5%. (Remove 4% from the butter amount.) 
  • Consider upping the cetyl alcohol. Go with 10% cetyl alcohol and see how that works for you. Reduce the amount of butter - cocoa or other - by 7%. You can try another fatty alcohol  - cetearyl alcohol will make it a little waxier, so try 5% with 5% cetyl alcohol or just 5% alone, and behenyl alcohol will make it feel powdier (5% to 10% is fine). 
  • Consider adding stearic acid. It will make the bar harder, but it might be draggier. Add up to 5% in addition to the cetyl alcohol. 
  • Put it in the freezer to cool, then remove them and put them in the fridge. Leave them a few days before using for the first time. And store them in the fridge in the warmer months. 
Let us know what you do next and how it works!

If you're a newbie, join us on Tuesday, June 4th for the Newbie Tuesday post on making solid scrub bars! 

Related posts:
Road trip essentials - solid scrub bars (with explanation of ingredients)
Formulating with oils - solid scrub bars
Using cationic quaternary compounds in solid scrub bars


magicsoap said...

Hello, Susan!

I've got an idea about Molly's questions of her scrub bar. It had never hardened becase of cocoa butter. I've passed through it in my solid lotions bar. Bars with 60-80% of cocoa butter were soft like cream!
I went to wikipedia ( and discovered that crystals of the cocoa butter after heating became less stable and it melting point decrease from 36 degrees C to 23 and even 17!
quotation from wikipedia: "Cocoa butter displays polymorphism, having α, γ, β', and β crystals, with melting points of 17, 23, 26, and 35–37 °C respectively. The production of chocolate typically uses only the β crystal for its high melting point. A uniform crystal structure will result in smooth texture, sheen, and snap. Overheating cocoa butter converts the structure to a less stable form that melts below room temperature. Given time, it will naturally return to the most stable β crystal form."

The remedies which works fo me are:
1. Time
2. Cooling and Whipping (using mixer with beaters)

Thank you for your blog!

Leslie Dimond said...

Hi Susan,

All of the recipes for scrub bars include sodium lactate but none instruct to mix with water. I have been using sodium lactate crystals and have assumed that even though they did not melt, the bar would get the benefit of them being in there. Should I first be dissolving the Sodium lactate in a little water? I have been making these for quite sometime. They are a very popular gift!

Thanks! Leslie