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.
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!
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.
If you're a newbie, join us on Tuesday, June 4th for the Newbie Tuesday post on making solid scrub bars!
Road trip essentials - solid scrub bars (with explanation of ingredients)
Formulating with oils - solid scrub bars
Using cationic quaternary compounds in solid scrub bars