I typically stick to cold process soap but I’ve been intrigued by the latest craze of fluid hot process soap (Fluid HP). I’ve been getting email after email asking questions, so I thought I’d give it a try and put together a tutorial on the process.

fluid hot process soap

The problem with standard hot process soap is that it can be to thick to color and swirl. At best, you can glop it into a mold, but certainly not swirl it. Soap makers have been experimenting with additives that make the soap looser and more easy to swirl. Here is my soap using this process! I am so excited about how it came out. It behaved perfectly and allowed me to swirl beautifully.

fluid hot process soap

How to Formulate a Fluid Hot Process Soap Recipe

The good news is you can use any cold process soap recipe as a hot process soap recipe. There are a few rules when making hot process soap. You want to use more water (if you normally discount) and you want to add additives that make your soap more fluid, such as yogurt, sodium lactate and sugar.

Here are some tips that I’ve come across when making fluid hot process soap.

  • Water – I’ve noticed many recipes call for you to use the standard 38% (water as percent of oils) that SoapCalc gives you. I personally used 2.5 times my lye and it worked great. The more you discount, the less fluid your soap will be. The more water you use, the more fluid your soap will be but you run the risk of shrinkage after the cure.
  • Sodium Lactate – Sodium lactate keeps soap fluid and also helps it to harden up. I use sodium lactate at 1 teaspoon per pound of oils. Using too much sodium lactate will give you a soap that is crumbly. The texture just gets weird. You can add sodium lactate to the lye when it has cooled off a bit or you can add it at the end when you add fragrance.
  • Sugar – Sugar helps with fluidity and it also boosts lather! I have no white sugar in my house so I used agave. You can also use maple syrup, brown sugar or honey. Use sugar at 1 teaspoon per pound of oils. Add it to the lye when it has cooled off a bit.
  • Yogurt – Yogurt helps keep the soap fluid. It has properties similar to sodium lactate. You can use yogurt at 1 teaspoon – 1 tablespoon per pound of oils. I used the high amount in the recipe below and used 1 tablespoon per pound of oils. Use plain yogurt.
  • Water Evaporation – During the cook you want the least amount of water to escape as possible. You can use press-and-seal or plastic wrap under the lid to help reduce evaporation. If lots of water evaporate then your soap won’t stay as fluid.
  • Don’t Stir Often – Stirring gives water time to evaporate, so minimize your stirring of your soap. During the cook, I only stirred once. Some soap makers don’t stir at all during the cook.

Using some of these rules, I created the fluid hot process soap recipe below. This recipes uses 32 oz. of oils and is palm-free. It soaped beautifully and I was able to color and swirl the soap. Check out this video that shows how fluid it is.

And as an added bonus, I was able to cut this soap after 4 hours! I am the world’s most impatient person when it comes to cutting soap so this was perfect for me. 🙂

Fluid Hot Process Soap Recipe

Coconut Oil – 10 oz. (31.25%)
Shea Butter – 6 oz. (18.75%)
Avocado Oil – 2 oz. (6.25%)
Olive Oil – 12 oz. (37.50%)
Rice Bran Oil – 2 oz. (6.25%)
Sodium Hydroxide – 4.42 oz.
Water – 11.3 oz.
Sodium Lactate – 2 teaspoons (added to lye water)
Agave (or sugar) – 2 teaspoons (added to lye water)
Yogurt – 2 tablespoons (added to cooked soap)
Essential Oil – 1 oz. (added to cooked soap)

Safety Warning – Gear up in your goggles and gloves before making soap.

Step 1 – Weigh your water into a container. Weigh your lye into another container.



Step 2 – Create your solution. Sprinkle the lye into the water while stirring, until completely dissolved. Be sure to mix in a well-ventilated area. Set aside to cool a bit.


Step 3 – Weigh out the coconut oil and shea butter and melt. You can let it melt in the crock pot but I’m too impatient for that. 🙂


Step 4 – While that is melting, weigh out your liquid oils into the crock pot.


Step 5 – Now that your lye solution has cooled down a bit, add the sodium lactate and sugar. I used agave and it turned my solution bright red!


Step 6 – Once your coconut and shea are melted, add them to the crock pot. Be sure to scrape every bit out.


Step 7 – Pour the lye solution into your oils and bring to trace. I don’t think temperatures matter very much. Heat will just make your soap trace faster, which is okay for HP.





Step 8 – Once you reach trace, cover your crock pot and set to cook. I put my crock pot on high. I used plastic wrap to help with water evaporation.


While the soap is cooking you can pre-mix your mica if you want. I just simply mixed 1/2 teaspoon of mica with about 1 teaspoon (maybe a bit more) of olive oil. I used some mica from Mad Oils – Snow White, 3 Olive Martini, Voodoo and Macy Gray.




You want the soap to gel and fully saponify. You’ll notice that it starts turning translucent. You can barely see in the photo below, but the edges start turning first. They get darker in color and turn gel-like.


After it had cooked for about 15 minutes I gave it a stir. You don’t have to stir it. You can just let it gel. I couldn’t help but stir.


You can tell it is not done because it hasn’t all gelled and it is still quite opaque and thick. Certainly not fluid. I covered it and cooked it for another 15 minutes.

After 30 minutes the soap was done. I zap tested it. To do that I stuck a wooden craft stick into the soap and coated it thinly. Then I blew on the soap to harden it a bit (you don’t want hot sticky soap stuck to your tongue). Then I touched it to my tongue. No zap! This means that the soap is cooked to neutral.

Step 9 – Once cooked, add the yogurt and essential oil and stir. You can let it cool down a bit. The more you let it cool, the more it will solidify, but it does stay fluid for awhile.




Step 10 – I divided the soap into four containers and colored each one. The soap stayed nice and fluid as I worked with it. It did solidify a bit on the top, but you can just stir it back in.




Step 11 – For the design, I decided to do a simple spoon swirl. I simply spooned the soap into the mold, rotating colors.




I used a wooden craft stick and swirled the inside. Fluid hot process soap tops won’t be as even and smooth as cold process soap tops. I used my spatula to smooth down the top a bit.

Step 12 – Let your soap fully harden and then cut! Mine took about 4 hours to fully harden (in the fridge). I was able to unmold and cut the same day that I made it.

hot process swirl

fluid hp soap

I do recommend that you cure your fluid hot process soap. Since it is fully saponified you can use it upon unmolding. But it will be a much better bar after some of the water evaporates during the curing process. I recommend a 2-3 week cure.

I hope you enjoyed this fluid hot process soap tutorial!

Happy Soaping!

-Amanda Gail