Hot Process (HP) Fluid Method (simple version)

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Techie Joe

Well-Known Member
Apr 1, 2018
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Hot Process (HP) Fluid Method (simple version)
.. From the video: Stick Blender Hot Process from start to finish
.. Expected duration: Under 30 minutes (not including preparation)
.. (video included below - 44 minutes)

. Large Pot (much bigger than your batch to allow for expansion)
. Stick Blender
. Stirrer / whisk
. Moulds
. Safety gear and thermometer

Ingredients (your own recipe):
. Oils
. Caustic Soda (Lye)
. Water (distilled or purified)
. Additives; essence, colours, clay, etc

Have additives and moulds ready before you begin

Heat the oils in the pot to 76-85 c (170-185 f)
Remove from heat source
Make the Caustic Soda solution and add to the Oils immediately

Stir and blend intermittently until light trace
Blend-in clay if desired
Keep blending and stirring past thick trace until the batter gets thinner (like applesauce)
No more blending from now on, only stirring

Watch for first volcano (expansion), then whisk / stir it down, its only bubbles
Use silicon stirrer to keep batter off the sides of the pot throughout (thru) the process

Stir occasionally but let it cook aswel, the mix should still be generating heat
(the more you stir the more water evaporates and the thicker your mix will be)
Watch for the second volcano

During second volcano, keep the mix stirred down to let bubbles escape, this should last for a minute or two
Once both volcano stages have stopped, the stirring sound will change to a sticky one as it is now the Gel stage
At this point your mix is 98% done, clean sides of pot and let the mix sit for a moment

Put your hot additives in and mix them, make sure the pot sides are clear of soap
If your mix is too thick you can add a little hot oil or something (suggestions welcome to suit your recipe)

Your mix is DONE and ready to pour into moulds or separate into jugs for colouring :)

Your soap should be ready to de-mould and cut after about 12 hours depending on thickness
You can use it straight away but its recommended to cure it for at least a few weeks so the moisture can fully evaporate

A lower oil temperature will make less volatile volcanoes

Test PH as you wish after the second volcano, but remember the mix is still very hot
Touch some mix onto your tongue (zap test), it may be several seconds before you can sense anything

The mixture should stay hot during the entire process
A temperature of at least 82 c (180 f) is needed to complete this process

Use only hot additives not cold, to prevent seizing of your batter

Mixing Caustic Soda, always wear long sleeves, gloves and safety glasses to fend-off splashes, vapours and what I like to call "microscopic caustic fireballs"

I would love to hear of tips and improvements to this method

Good luck ;)

(Edited to exclude "slow cooker" as it is too hard to control the heat with them. Also included "thermometer")
Last edited:
The main points (for writing on a post-it)
  • get everything hot and start the mixing / blending
  • blend until applesauce stage (after thick trace) then stop
  • stir occasionally until gel stage (after second volcano) then stop
  • add fragrance and pour
I think we talked about this before.
But IMO it is a waste of my time to sit and babysit that.

Also it is not any more fluid

Also I tried to do this, with heat still on and , yeah no. so not worth it.
You don't save any time, cure time, and it takes way too much work
I've never had hp that fluid if I'm honest. In the video comments he says that the oils were 16lb and the total weight was 26lbs. I'm wondering how much water was put in, if that is a bigger factor. But it does looks very good at the poring stage
I watched the video again as the 1st time was a while ago. Way to long a video and way too much talking
Of COURSE it is more fluid. He added a Super Fat, Milk and scent. If I did crockpot cook and then added all that at the end I would have something similar.
But yes we are not sure what his water percentage is so :smallshrug:
I await your postings of your experience with this method. Please post photos, too, if you can. I hope you don't start with such a large batch, though! Well, of course that's up to you, but I like starting with small batches for new methods and new recipes.