Come along with me on this Dr. Bronner’s factory tour of the Pure-Castile Bar Soap production! Making quality bar soap on this large of a scale is tricky business. Liquid soap is a cinch in comparison. With liquid, you functionally throw all the ingredients in a pot and out comes the soap. Bar soap is more complicated. The ingredients all go in as a liquid, but they need to come out as a solid! That takes a lot more doing.
That’s one of the reasons I brought you my tour of our Liquid Soap Production first, years ago, but put off attempting to explain to you bar soap production until now. Honestly, it’s a bit nerdy, but I have full confidence that you will appreciate it just as much as I do. After all, chemistry is gorgeous.
The Chemistry of Bar Soap
Because bar soap production happens inside a closed system, I can’t show you the chemistry in action, so I’ll have to describe it for you. Inside the tubular reactor in the video (does “tubular” make anyone else think of the Ninja Turtles?), I want you to envision a collision between oils and alkali which blasts apart all the molecules so that they reorganize as soap, glycerin, and water, with nothing leftover. It’s so efficiently beautiful! A few more ingredients get mixed in to the liquid before it begins the process of drying out. First, most of the water content is extracted in a vacuum chamber as a vapor. The water vapor runs through the cyclone separator so that any soap content that got caught in it can be pulled out and the water can be treated for reuse. The remaining soap then gets cut into “noodles,” which you see in the video, and it continues to dry as it cures in the supersacks. Personally, I think the soap noodles look like cheese curds.
The essential oils don’t get added until the finishing line. When you buy essential oils for home use, they usually come in a 1-ounce bottle, or possibly smaller. We buy them in 55-gallon drums, which is equal to 7040 ounce bottles, and can cost over $20,000!
So sit back and enjoy! Be hypnotized by the honeycomb screens. Get mesmerized by the stamper. I hope you’ll agree with me that soapmaking is really nifty!
Want more soap chemistry? Check out my article “How Soap Works.”
Asking how the Bar Castile differs from the liquid? Read my article “Liquid vs. Bar in Dr. Bronner’s Castile Soap.”