Making hard bars of soap..

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New Member
Jun 12, 2008
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I work for a biodiesel shop and we just started experimenting with hard soap production from the glycerin. Our recipe thus far is:

1 liter glycerin
250 mL H2O
38 g lye (sodium hydroxide)

Now we are trying to make our bars a little more hard. We hear coconut butter is a good hardener. What type of coconut oil are people usually using? Natural or refined? Is there a dramatic difference between the two?

Any information helps! Thanks!

-Dickinson College Biodiesel Crew
Coconut 76 or you can use 92

Palm makes soap hard.. so does Palm Kernel.. Babassu Oil. Cocoa Butter..
I use refined coconut oil 76 (liquid at 76 degrees F). Coconut makes a hard bar that is also very bubbly. Tallow makes a good hard bar, too, but it's not as bubbly on its own as coconut or palm kernel or babassu are (the 3 top bubbly lathering oils, which also make hard soap). I like to formulate a good hard, bubbly soap by mixing tallow with some of the more bubbly oils and a conditioning oil.

does your glycerine carry an odor through from the biodiesel process??? I ve heard some people say it does a friend that makes bio too. :)