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Tuesday, July 29, 2014

Castile Bar Soap

Olive oil castile bar soap
Olive oil castile bar soap
Castile Bar Soap

While waiting such a long time for the liquid castile soap recipe to become translucent, I made my first set of castile bar soaps using the cold process method.  I have to say, I may prefer the cold process over the liquid process, because it seems to go so fast.  I found the recipe online, and tailored it to the amount of olive oil I had left over using the Brambleberry Soap Calculator.

There are two attractive aspects of this recipe.  First, because of the liquidity of olive oil, there isn't any rush and no seizing of the soap mix.  Second, it cures in at least four months rather than the traditional 12  plus months for most castile bar soap recipes. This is due to the significant reduction of water that directly reduces the evaporation and hardening time.

Olive oil for castile bar soap
Olive oil for castile bar soap


  • 567 grams (20 ounces, 80%) olive oil
  • 72 grams (2.546 ounces, 10%) Sodium Hydroxide (NaOH lye)
  • 72 grams (2.546 ounces, 10%) of water

Self labeled vinegar spray tottle
Self labeled vinegar
 spray tottle


  • Stick blender
  • Stainless steel pot
  • Stainless steel spoon
  • Pyrex measuring cups
  • Kitchen calculator
  • Vinegar in a spray bottle

The Process

Put on your long shirt and pants, grab the goggles and rubber gloves.  Walk the lye and water outside, or take everything outside (which is what I did).  
Equal parts water and lye
Equal parts water and lye
  1. I weighed the olive oil, and put it in the stainless steel pot.
  2. I weighed the water in a large pyrex measuring cup.
  3. I weighed the lye in a pyrex cruet.
  4. The lye was added to the water in the larger pyrex cup, and stirred up with a stainless steel spoon (it takes a bit longer for the lye mix to become clear due to the 50/50 ratio).
  5. The pyrex cruet was sprayed down with the handy vinegar sprayer while the lye was dissolving.
  6. The lye was slowly poured into the olive oil while the hand mixer was on low.
  7. After the oil became as thick as it could, the mixture was poured into one of my old soy milk cartons
    100% olive oil castile soap in milk carton mould
    100% olive oil castile soap in
    milk carton mould
    for curing (maybe someday if I'm serious about this I'll put together an actual soap mould).  I like the idea of square bars.  Then again, round soap from pvc pipe is super cute!  I didn't bother covering it for the gel process, as it has been indicated that the gel process isn't really a necessary part of the saponification process.
  8. Tools were sprayed down with vinegar, then filled with water to prepare for cleaning.
  9. I couldn't resist giving it a bit of a squeeze after 24 hours.  It felt pretty firm at the top and bottom ends, a bit of give in the center.  Not ready.
  10. In total, I waited 48 hours for the soap to harden enough for cutting.  The carton was peeled away from the soap, and the soap loaf laid on a long side to prepare for cutting.  The loaf is a bit odd shaped, and I wanted the
    Olive oil castile bar soap loaf
    Olive oil castile bar soap loaf
    bars to be about an inch thick.  I marked the loaf where the bars should be cut and used a large knife to complete the separations.  I wasn't happy with the way the soap cut.  It seemed a bit brittle, and the cuts weren't smooth.  This is typical when cutting with a knife.  
The center of the soap ended up with a dark ring.  This goes back to the gel phase, and insulating or not insulating to control or prevent the gel phase.  It's explained more in a reddit post.

Olive castile bar soap, after cutting
Olive castile bar soap, after cutting
Eventually, the darker spots won't look so different from the rest of the bar.  I think I'll be making more of these in the near future, but will look at other options for cutting the loaf.  These bars need to be set aside for four months at minimum to complete the curing process.

After curing, you can use the bar soaps to make some super creamy liquid castile soap, as described by frugalberry. This will result in opaque liquid soap.  For clear liquid castile soap, follow my earlier recipe, First Stab At DIY Liquid Castile Paste.

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