More than once, a person browsing my table at a market has said something to the effect of "handmade soaps are so neat, but they don't really lather that well, right?" Which has surprised me and also led me to believe that this might be a common misconception if more than one person believes it.
The thing is, no two soap recipes are identical and some ingredients suppress lather while other ingredients encourage it. So I wanted to share a little bit about soap ingredients, what they do and how it's possible to create a wonderful lather in a handmade soap.
Things That Increase Soap Lather
Let's start with ingredients that help improve lather.
Oils and butters all add different properties to a bar of soap. Some of them have a higher cleansing value (meaning they can strip the skin), others have a higher skin conditioning value (meaning they add moisture to the skin). Some add to the hardness or softness of the bar, and others contribute to lather.
- Coconut Oil - This is the number one soap making ingredient for creating lather with big, luxurious bubbles. But there is a fine line here. If you use too high of a percentage of coconut oil, the soap will dry your skin and leave it feeling tight and itchy. If I purchase from another maker, I'll never buy soaps where coconut oil is the first ingredient for this reason.
- Castor Oil - This is often used in a low percentage in soap recipes. It adds a creaminess and some smaller bubbles to the lather. Oddly, castor oil doesn't lather on it's own - but in combination with other oils it improves the lather quality.
- Sunflower Oil - This oil helps to stabilize the lather so it doesn't disappear right away.
Using the right additives can significantly increase the lather of soap. Anything with a high sugar content will help with this. I've used all of the following to boost the lather in my soaps.
- Aloe Vera - I use aloe in all of my soaps. It is a skin soother and is a natural saponin (meaning you can achieve a lather just by using the plant - similar to soap nuts).
- Beer - Hops are really great for the skin and the sugar content of the beer increases lather so much. It's not my favorite ingredient to use in soap, though, because adding lye to it can cause fizzy beer to volcano out of the mixing container. It takes a lot of extra care and it makes the house smell awful!
- Milk is also great for the skin and does wonders for lather.
- Juice or Puree from fruits or vegetables
- Clay (no sugar, but it still works)
To learn more about soap additives and lather, there was a really great lather experiment hosted by Kenna of Modern Soapmaking.
Things That Reduce Soap Lather
If you have encountered a handmade soap with poor lather, there are a few things that can cause this.
Single Oil or Single Fat Soaps
Some people like to make castile soap, which is made with 100% olive oil. While it's very gentle on sensitive skin, it tends to be a slimy bar with very little lather. And it has to cure for a full year before using, so by this time many fragrances will have faded away.
100% lard soaps make a hard bar that is creamy and conditioning when used; but again, very little lather. Most other oils, fats and butters can't be used in this way. The final bar just comes out gross.
Superfat is a term used in soapmaking that means a lye deficit. You use less lye than is needed to fully saponify the oils (saponify means turn into soap). Soap makers pad their recipes with a minimum of 5% superfat to ensure they don't accidentally create a harsh bar. I use 6-7%, others use 8% or more. Using a superfat allows some of the oils to remain behind on the skin for moisture. But the higher the superfat, the lower the lather.
Too Much Butter
While shea, cocoa and other butters are amazing ingredients for the skin, these ingredients are also known to kill lather.
If there is a lot of magnesium, calcium and/or iron in your water, these metallic ions interact with the soap molecules and reduce lather. The only way to get around this is to either soften your water or use a product with a harsher synthetic surfactant instead (like body wash - ugh, plastic waste).
As you can see, there are a lot of variables that contribute to lather quality in soap. So if the only handmade soap you have ever used had poor lather, please consider trying one from a different maker!