Friday, August 31, 2012

Hot Process Soap Making- Oven Method

When I first made soap, I was terrified. Lye was some magical and deadly substance that I feared more than being dirty. But I gathered my courage and my supplies, researched all I could find on the subject, and jumped in. After my first batch, I wondered what all the fuss was about. I hadn't died. I hadn't been disemboweled. My family wasn't a bunch of mutants blinded by the lye. And I can still pick my nose with all ten fingers, though the thumbs still give me fits. 

All kidding aside, lye should be respected as a chemical that can cause severe burns,etc. But when first making soap, relax and enjoy the experience. Follow whatever instructions you've found to use with care, but not fear.  You can do this. It's not difficult.

For those of you who have never made soap, there are two main types of soap making- cold process and hot process. The difference is this. In cold process, the lye mixture and fats/oils must be of similar temperature when combined. Then they are poured into the mold and left to cure for several weeks. If you use the "soap" during this time it will burn your skin as the lye has not turned the fats/oils into soap (saponification) and so is still very caustic. This process makes very creamy bars but takes weeks until it can be used. I like instant gratification.


I use the hot process method. This method cooks the lye/oils/fats together until the fats saponify. Once this is accomplished the soap is done and ready to use. I have tried several methods for this- crock pot and oven.  The oven, for me, is the easiest and quickest with the most consistent results.

Gather your equipment and ingredients. At the end of this tutorial, I will give you a basic recipe using basic ingredients, so you can give this a try without going into debt. Of course, feel free to go into debt buying all the cool fats and oils, scents and colorants. But it's not necessary to make a nice soap.

Things you'll need:
1. ingredients
3. a mold of some sort
4. glass measuring cups
5. wooden spoons
6. goggles and gloves
7. a stick blender
8.dishes to measure your ingredients into

Now let's begin. 

Measure out your fats (oils, butters).

Mix your measured lye into your water. Don't add the water to your lye or you will see your very own molten volcano. Stir until the lye is dissolved. Watch out for the fumes. I just reach my arm over to stir that way my face is not above the liquid.

Add the lye solution to the melted fats.

Use your stick blender to mix until it reaches trace.

Trace is when you lift your spoon or mixer up and the drops drip down and remain on the surface. It's hard to see in this photo, but the drips are staying on top.

Make sure your pot is only half full or transfer to a larger pot. This is because the stuff will expand and overflow if you don't have enough room.

Stick in a pre-heated oven at the lowest temp. Mine is 170 degrees. Set your timer for 30 minutes. Stir at 30 minutes. Set for another 15 minutes. Stir and check. Keep doing this until your mixture looks like applesauce.

Remove from the oven and stir to cool a bit. It should now look like mashed potatoes.

Now is the time to add your scents, colorants, and any other items--exfoliants, herbs, etc.

After everything is thoroughly mixed in, pour it into your mold. Smooth the top and roughly tap your mold onto the counter to settle everything in. Now leave it to cool overnight or until solid.

When it's dry, unmold your soap loaf.

Now it's time to cut your bars.

If you're doing this for personal use, make your bars any size you like. I sell mine, so I cut them to be around 4oz.

And here they are. I made the larger two on the right for our use. I'm lazy and hate running downstairs to get another bar, so I like mine big.

I also cut a bar or two into four smaller bars so I can give them away as samples. They are also a nice size for taking on vacation. Once you use such a luxurious soap, you may never go back to using the shore-bought stuff. Especially in the winter!

Soap making is a fun project. It may not be cheaper than store-bought unless you figure in the amount of money spent on lotions and moisturizers in addition to your soap.

In the above tutorial I was actually making our shampoo bars. Below is the simple recipe I promised for soap.

15.2oz/431grms      water
5.6oz/159grms           lye  
16oz/455grms          crisco 
10oz/283grms         olive oil 
14oz/397grms    palm kernel oil 

There are loads of recipes on the internet. Pick a simple one and give it a try.  


  1. Thank you for these instructions! I've always done regular CP, but decided to give this a try. I left it in the oven at 170 for 30 minutes and it turned into a semi-solid mass! It was soft enough to stir and looked kind of like the mashed potatoes, so at that point I put it in the mold and then wrapped in a towel (habit). Hope it turns out! I will check it tomorrow. It wasn't ever at the applesauce stage for me.

    1. You'll probably see that your next batch is different yet.Did you do the zap taste test? That's my ultimate end test. If it doesn't zap your tongue, it's done, no matter what it looks like or what stages it went through. I have noticed that the heavier the trace you get to, the quicker it cooks up. I have also had batches take forever, like more than 2 hours, to cook. I started to worry, but kept at it and it finally passed the zap test. Thanks for stopping by. I hope your batch turns out perfectly for you!

  2. Aaaah, I left it in the mold, wrapped in a towel until 2pm (made it last night at 8pm). It's half gooey. Not sure what I did wrong. This has never happened to me, doing CP method. :(

    1. My guess would be that it needed to cook longer. Can you leave it in the mold? It will eventually cure like CP I think. I'm sorry it didn't work out this time. I hate it when I put time and effort into something new and it doesn't turn out. I hope you'll give it another try. If you want, you can email me at and I'll send my phone number and help go through it with you if you want to try again.

  3. I've left it in the mold. I checked it at 24 hours and it was firmer. No more gooey on the edges, but still soft in the middle. I will leave it longer. This is a very soft soap recipe anyway. I've made it before, but this time I tripled the batch. Thanks for your help. I'm going to try the CPOP method again with a different recipe of mine. :)

    1. When I unmold mine the next day (close to 24 hours), it is still somewhat soft, but firm enough to cut. It's just a bit sticky. I can still very easily push my finger into it. I leave the bars separated to dry/harden further. I'm glad yours hardened up a bit.

  4. I was able to unmold and cut my bars today after about 44 hours. I guess I don't see the point of oven process, if I still have to let my bars sit to harden/dry. This recipe is a pretty soft bar, so I might have to let it sit for a few weeks whether it's CP or CPOP. I still may try the OP for my Oatmeal Honey bars.

    1. The point is that you can use them right away versus having to leave them for weeks to cure. The cooking process causes the lye to turn the fats to soap more quickly than leaving it to cure slowly like in the CP method. The wait for CP is not to harden but to allow it to saponify. You can use your OP bars right away if you like. I usually take a bar or two right to the bathroom to use and let the rest harden. The harder/drier the bar, the longer it lasts. The same is true for CP bars, though. Even store-bought bars can harden further to make them last longer.

  5. Hi! I just found this post about hot process without a crock pot. I totally want to try it. Most HP tutorials use a crock pot but they are not very popular in Europe (I wouldn't even know where to buy one) so your tutorial sounds good :)
    One IMPORTANT question: You are talking about 170 degrees Fahrenheit, right?
    And can I ask about the recipe of the shampoo bar?

    1. Yes, Fahrenheit. :)
      Shampoo bar recipe
      382g coconut oil
      62g castor oil
      25g cocoa butter
      340g crisco
      408g olive oil
      123g rice bran oil

      Let me know what you think and how the process goes for you!

    2. Thank you so much!!! Yes, I'll let you know ;-) but only in March because I am currently on an exchange programme in Norway and only come back home in March. I'm just already planning the soaps I want to make after not being able to make soap for 7 months :)
      And one more question: Do you know how hard your water is? I read that hard water can effect the effectiveness of shampoo bars.. And I live with the hardest water you can get...

    3. I think our water is pretty hard. We don't soften it and I've not had any issues with my soaps. I'm not sure if you are talking about the water you use to make it or to use it, but you can use distilled, bottled water to make it.

  6. Hello, so happy to find this post! Did my first cold process soap today and just discovered it needs a month to cure I'm way too impatient, and I really don't want to invest in a crock pot again as I've just given ours away :( I can't wait to try this tomorrow!!!!! Thank you for sharing.

    1. I'm always impatient, too. That's the main reason I like this method. Good luck and let me know how it works for you!