Wednesday, March 3, 2010

Double Layer Cold Process Loaf

Happy Wednesday everyone! For this fun from-scratch project, grab your 2 pound wooden loaf mold and print out lining instructions here. We're going to make a simple and beautiful double layer cold process soap using the following basic recipe:

4 oz Canola oil (or olive oil)
4 oz Palm oil
4 oz Coconut oil
1.7 oz Sodium Hydroxide
4 oz Distilled water
0.7 oz Fragrance of your choice, I used English Rose for both layers
1/4 teaspoon color of your choice, I used coral mica for the bottom layer

3 Pyrex dishes, two medium and one small
Stick blender
Mug for portioning fragrance
digital scale
fork for stirring lye solution
2 pound wooden mold
freezer paper and tape (Scotch tape works okay, but masking is better)
color and fragrance of your choice
paper towels are very handy
oils, distilled water, sodium hydroxide

This recipe is for one layer. You will be making each layer separately instead of making one big batch and splitting it. By the time you have poured your first layer, washed your dishes and prepared the second batch, the first layer will have set up enough so that the second will sit on top of it instead of pouring right through. Below is an example of a lined mold with freezer paper, shiny side up.

Make sure you have read up on safety precautions when using sodium hydroxide before attempting to make soap from scratch. Sodium hydroxide, or lye, is a caustic chemical that must be handled with caution and in a well-ventilated space. This also means suiting up in rubber gloves and goggles (in addition to your glasses) and wearing long sleeves to protect your arms. Have everything you need set up before you start so that all you have to do is pour and mix.

Measure out your melted oils, the dry sodium hydroxide and fragrance. Use the little Pyrex dish to measure out the sodium hydroxide dry before adding it into the water. If you are weighing out the sodium hydroxide while pouring it into the water on the scale, you might just slip and pour too much or even pour out a big clump that could splash up the water. Always pour sodium hydroxide into the water to avoid a "volcano" situation, and mix while you pour to avoid lye clumping on the bottom of your dish. Above are the oils and below is the lye mixture doing it's thing. It's hard to see, but there's steam rising from the lye water and the temperature started at about 165 degrees F. and dropped fast, which is actually a bit cooler than the 4 pound batches we make in class that get up to about 180 degrees. Oils and water should combine to be about 200 degrees.

I like to mix my color in the oils before I add the lye because I don't have to worry about reaching trace and running out of time just when I'm doing the coloring part and haven't even put fragrance in yet. Below shows the colored oils with about a 1/4 tsp. of coral mica being blended with the lye solution and reaching trace.

When you reach trace, or the point where when you lift your stick blender above the soap, it is thick enough to leave a visible trail on the surface, you can now add your fragrance and keep mixing. Sometimes, the fragrance will thin out the trace a bit, or even speed it up. One you have thoroughly mixed in the fragrance (0.7 oz), pour into the mold and start washing dishes so you can do it all again-- it's worth it!

For a pretty contrast, I left the top layer the natural color, but feel free to mix and match any color in the rainbow. Below shows layer number two being mixed and poured. Don't forget to fragrance this layer, too (another 0.7 oz). It's also really fun to do a different scent in each layer to create a unique blend when smelled together. Well, you know, to an extent... not sure if wasabi and carrot cake would smell so hot ;-)

You can take the soap out of the mold the next day and cut off a piece, but remember to wait the full month before using it so the lye can neutralize. Hey, these might even make a pretty good Easter gift with a bow around the middle of the bar! Have fun, and please let me know if you have any questions.


  1. Hi Soap King!

    Those soaps look incredible :)
    How much time had lapsed from the first pour to the time you poured the 2nd layer?


  2. Lovely layers! I know I usually just split my batch and let about meh, 5 minutes elapse between the first two layers but it's not a precise science =)

  3. Hi Rose! It took me about 15 minutes between layers, but like A-M said, there's no exact amount of time. However, if you pour one right after another, they will blend together, which is perfect for swirling!

  4. Wow, these are really pretty soaps, thanks for sharing!!

    I am thinking about trying this recipe out, but I have a question about the colorant and FO - is it .7 oz of fragrance per layer (so 1.4 oz total) and then 1/4 tsp. colorant for the bottom layer? (I think you might have mixed up these two in your instructions) I just want to make sure before I start. Thanks again!!

  5. Good eye Denette! You are totally right, 1.4 oz fragrance total and roughly 1/4 teaspoon of color for the bottom layer. Thanks for the compliment!

  6. my layers came apart, what now use glue..


  7. Great layers!

    I had a problem with my layers separating in my soap as well. That's when I googled 'layering cold process soap' and this site came up.

    I'm wondering if certain recipes don't work as well for layering. My recipe had lard. I also use a lot of fragrance in my soaps so I'm wondering if that could have caused a problem.

    Anyone have any ideas for troubleshooting layers that separate?

  8. spray your first layer with a fine mist of rubbing alcohol just before you pour the second layer on top of it.