Recently I made 2 simple soap each with an interesting additive that would affect the way a soap lathers. These 2 are made with the exact formula and superfat percentage, one loaf made with one added organic egg (see blog post What Does Egg Contribute to Soap?), the other made with 3/4 tsb bentonite clay (Plain White Soap, Really?!). Now I'm going to talk about the different kind of lather these 2 produce.
The egg soap produces suds texture very close to what you get when you beat an egg white with high speed electrical beater like you are making whipped cream. The bubbles are very uniform in size. It starts big and fluffy, then slowly turns into denser foam. It feels really airy and weightless, like washing with cloud (I would imagine that's how it feels like if cloud is actually reachable!) Now that I think about it, it's almost like the same feeling I get when I use the bottle foamer to pump my liquid soap, uniform airy and weightless!
Then I tried the bentonite clay soap. It starts slow, then bubbles up consistently, but surprisingly not uniform in size. See the photos yourself! It creams up and produces slippery foam that feels dense and with weight.
I let the foam sit for few hours, in both cases. When I came back from dinner, the foam from egg soap already disappeared to nothing which is expected, but the foam from bentonite clay soap still there in tact! Except, it's all dried out, interesting isn't it?!