Blue Aspen Originals

aspen leaf
Fine soaps hand crafted in small batches

Guide to Cold Process Soap making

I hope you find this tutorial helpful. It is currently a work in progress as I will be adding more photographs and explain some of the steps more clearly. It has taken me 3 batches of soap to get all the pictures I needed for this page so you will see different colors of soap in the pictures. Visit my page on swirling to learn the technique I used on these batches.

1. Once I decide on what kind of soap to make, my first step is to take out all my soap making utensils (scale, oils, lye, pyrex measuring cup, wooden or stainless steel spoons, stainless steel pot, mold, fragrance, recipe). I have several variations of the same recipe depending on what oils I intend to use with it, sometimes its my basic recipe with extra cocoa butter or extra hemp seed oil or shea. Each variation has been calculated out using Majestic Mountain Sage's Lye Calculator because each oil has a different saponification value (a saponification value is how much lye it will take to turn the oil to soap, it is different for each oil in the recipe. DO NOT adjust your recipe by doubling the ingredients, halving the ingredients, or change oils without recalculating the recipe! You could end up with lye heavy soap or soap that may go rancid because there is too much oil.) I keep all my recipes on individual index cards in a recipe box and take out only the one I intend to use. I use my kitchen as my soap making area so I have access to the stove and sink and lots of counter space to work with.

all my supplies My soap making supplies. Stainless steel pot, pyrex measuring cup, plastic spoon, stick blender, postal scale, Red Devil Lye, orange plastic container to measure lye in, gloves, safety glasses, mold and soap cutter (taping knife from hardware store).

2. I first measure out my lye, I use a plastic container tared (zeroed out) on my scale to measure lye into. I then measure out my water into the pyrex cup, I don't weigh my water, just use the markings on the side of the glass (water weights the same as its liquid volume) and it doesn't have to be exact. Just don't go over or under too much. I calculate my water 25-30% less than what Majestic Mountain Sage's Lye Calculator recommends to avoid making the soap too soft & having large amounts of bar shrinkage during the cure. I then place the pyrex of water into the sink and slowly pour in the lye as I stir. Always pour the lye into the water and not the water into the lye or it can cause a volcanic eruption! Please remember to wear gloves and glasses in case any lye water splashes up ( I had an accident when I was on a scientific cruise where I opened a bucket of Formaldehyde causing it splashed in my eyes, I was very lucky and learned a valuable lesson on stupidity that day. Don't push your luck when it comes to safety). Stir the water until all the lye has been dissolved, this mixture will heat up and give off strong fumes so be careful. Open windows and turn on the fan above your stove to help dissipate fumes from the lye. Once I am sure it has all been dissolved, I fill the sink with cold water halfway up the side of the pyrex to help cool the mixture down while I am measuring out my oils.

Adding lye to waterAlways, Always add your lye to the water! Wear your safety equipment!

3. In a stainless steel pot tared on my scale, I weigh out the hard oils (palm, coconut, palm kernel, shortening, stearic acid, beeswax, cocoa butter, etc.). I put the pot now containing the hard oils on my stove at low to medium heat to melt them all down. While the hard oils are melting, I measure out my liquid oils (olive, canola, soy, hemp seed, etc.) into a plastic bowl.

melting oilsOils melting on the stove. I save the liquid oils to add after the solid oils are melted to help cool it down.

4. While the hard fats are melting I line my mold. My favorite mold is from TLC Soaps & Sundries It is the easiest to line, I use a plastic grocery bag and the vinyl inserts and I am done! I also have a 8 1/2 x 9 x 5 inch wooden box that I constructed and line that mold with freezer paper (glossy side toward the soap). I use two overlapping sheets of freezer paper, arranged perpendicular to one another and creased into the corners of the mold. I tape the edges of the paper to the side of the box mold to hold it in place. My third mold is 2 1/2 inch PVC pipe, for round bars. I have a coffee can of canning wax I melt on the stove, spread shortening inside the PVC pipe and line the pipe with freezer paper. The shortening helps keep the freezer paper to the sides of the pipe. When its lined I place the PVC into the wax and let it cool to plug the bottom end. I also sometime have individual shaped molds ready incase I made a little too much for my mold and can pour the excess into these smaller molds. Usually the case when I add the whole MMS recommended amount of water.

My TLC mold with liners in place

My 3lb TLC mold with plastic liner bag (inside out so ink doesn't come off on soap) and acrylic liners holding it in.

5. When the hard oils are all melted I take the pot off the stove and pour in the liquid oils to help cool down the mixture. I put the pot into the sink with the pyrex of lye water to cool them both down. Sometimes I will put the pot of melted oils on my scale (with a hot pad between the pot and the scale) and just pour my liquid oils directly into the pot. By saving the liquid oils to add after the melting, it helps cool the mixture down faster.

adding liquid oilsHere I am adding the liquid oils directly to the melted solid oils. If you do not feel like you will measure accurately enough measure them into a bowl and then add them to the melted oils. This just saves me extra dishes to clean.

Lye solution and oils cooling in the sink.

My pyrex of lye solution cooling and my pot of oils cooling in a sink of water.

6. When the temperature of the fats is between 90- 110 degrees, and the lye water is close to that I prepare to mix them. I used a thermometer in the beginning of my soap making career but soon learned to feel the sides of the pot and pyrex to make sure they are cool enough and close to the same temperatures. Make sure to rinse the thermometer and stirring spoon of the lye water, then keep them in the sink to be washed later.

7. Gently pour the lye water into the pot of oils, careful not to splash. I sometimes have my spoon and slowly stir the water and oils together as I am pouring. When the pyrex is empty I put it in the sink and let it overrun with cold water. After stirring with the spoon for a minute I switch stirring with my stick blender. I put the stirring spoon in the pyrex to wait for cleanup. I run the stick blender for quick 15-25 second burst and stir with it turned off (as if it were a spoon, to not over heat the motor) in between running it. If I am coloring the whole batch or adding titanium dioxide to whiten the base I will add it now and use the stick blender to break up any globs and try to get the soap smooth.

pouring lye mixture into soapCarefully pour the lye/water solution into the oils.
Try not to splash.

soap being mixed

Here the lye water and oils have been mixed together. Notice the soap is not sticking to the stick blender or leaving a trail in the soap as I stir.

8. When the mixture starts to thicken slightly I lift the blender (turned off) out of the soap to see how well the soap puddles from the blender to the surface of the oils in the pot. Before the soap gets too thick (keep checking how well it puddles, now it should all melt quickly back into the oils in the pot, it will trace when the oils dripping from the stick blender onto the surface creates slight ridges like they would in pudding. Trace also can be explained when your stirring spoon or stick blender leaves trails in the soap that takes a second or so to incorporate back in.) Also, it gets thick enough to coat the mixing spoon or stick blender.

Soap at traceHere you can see the soap is coating the stick blender and has reached trace. You might be able to see the second arrow is pointing to the trails left on top of the surface from the dripping soap. Please notice the soap is darker, that is because I added my fragrance oil before I took this picture, its the only one that shows trace well. When I get a better picture of what trace is I will post it.

9. Once trace happens I add in the fragrance. If it is an essential oil I don't have to worry about it accelerating the trace as they usually do not have that tendancy. Some fragrance oils will behave well and some will speed things up. I pour the scent oils into the pot and quickly stir them in with the stick blender OFF, then I give it another quick burst by turning the blender on to make sure its stirred in well. When the soap is getting slightly thicker but not to the pudding stage, I add in my lavender buds, oatmeal, scraps of colored soap, etc. You do want it thick enough so they don't all settle down to the bottom of the soap but thin enough to pour easily into your mold without creating air bubbles.

Adding scentHere I have a measured amount of fragrance oil I am pouring into the soap mix.

10. When all my additives and swirl colors are in and the soap is pudding thick I pour it carefully into the mold. Use a spatula to clean off the stick blender, unplug it first, then put that in the sink to clean later. Then I use the spatula to scrape all the soap out of the pan into the mold. I knock the mold on the counter a few times to help release any air bubbles that might be trapped (usually the case in PVC molds).

Soap poured in the mold My soap with red swirl poured in the mold.

11. I cover the top of my molds with plastic wrap to help keep soda ash from forming. I then cover my log mold with a piece of cardboard or a thick towel to help insulate it for 24 hours. If the soap contains any honey or milk DO NOT insulate it as those ingredients will heat the soap up sufficiently for a nice gel stage. Gel is when the soap heats up and goes through the chemical reaction necessary to turn the oils and lye into soap (saponification). Do not worry if your soap doesn't go through gel, it will still be soap. The saponification process is slower and may take some more time to complete. It is usually the case for soaps poured into small molds that I don't insulate.

Soap covered with plastic

Soap covered with plastic to decrease chances of soda ash forming. In this case I have used some of the plastic bag lining the mold to cover the soap. On top of the plastic I have put a light towel.

soap insulated with a light towel

12. Now is time to clean up. I only wash my spoons, stick blender, pyrex and margarine container ( if its stained real bad from the oxides I will throw it away) at this time. I let my soap pot sit for a day so it will turn into soap. This way when I wash the pot I can see how well the soap lathers and looks by what was left in the pot. If you want you can wash it the same day you make soap, I just enjoy doing it the next day when its soap and not a bunch of oils.

Notice how thick the soap is

Notice how thick the soap is in the bottom of the pot. It's heavily traced like thick pudding. Not much to clean up if you save the soap pot until tomorrow to clean (so all the mess is soap and not a mixture of lye and oils). Usually I toss the plastic container I mixed the oxide in as well because it is a mess to clean.


13. After some time in the mold the soap will heat up and start to turn almost clear. This stage is called the gel stage. It is the lye and oils going through the saponification process to make soap molecules. Not every batch of soap will gel, it might just take that batch longer to cure and become mild.

Gel stageThe circle I drew shows where the center of the soap is starting to turn translucent and gel. It will get very soft at this stage. You want to keep as much heat in as possible to help the saponification process.

14. After 24 hours I unmold my soap. My log mold from TLC Soaps & Sundries is the easiest. I pull the plastic out and pull the acrylic inserts off the soap block (sometimes I have to cut it off with an 8 inch taping knife from the hardware store) If the soap is still soft ( I like to use castor oil in my recipe and that takes a little longer to harden up) I will let the block of soap sit and 'dry out' for another day before cutting. The TLC mold has a built in 'miter box' on one end that allows you to cut perfect bars of soap. I also use the log mold for cutting my PVC soaps because it works well cutting those bars straight. I also can not stand a bar of soap that is not beveled on the corners, not sure why that is. I use a regular 'Potato Peeler' and cut off the corners and edges of all my bars. ( I have gone a week once without beveling the corners and just couldn't stand it anymore, grabbed the peeler and 'fixed it'). I now use plastic stacking sorting bins that you can find at office supply stores (the typical "In" box, "Out" box space saver) that I use for curing/storage racks. They work great and I can get a lot of soap into less space to allow them to cure. Soap needs to cure for 3-4 weeks to loose most of the water used to make it. This makes the bars last longer. Also the saponification process needs to complete, this can take up to 2-3 weeks because no heat was added to the process to hurry the chemical reaction along such as using the Hot Process Method.

Removing acrylic liners Here is the soap about 24 hours later. I have removed it from the mold, pulled the plastic down the sides and start removing the acrylic liners with a taping knife.

Cutting Bars

Cutting bars using the built in measuring device on the TLC mold. All my bars are cut straight and the same size.

15. Packaging soap. I like to label my soaps with a 'Cigar band' style label. It wraps around the soap leaving 2 ends exposed and is quick and easy to do. I use any word processing software and can get 4 labels on one sheet if I have it set landscape. Currently I am using Microsoft Publisher to create my labels. I just have a template that I set up and when I need to make labels I customize the template for that particular batch (change ingredients, name of soap things like that) and print them off on nice paper. I also have found having generic labels ready saves in a pinch as well. I have a space on my generic labels to write in the soap scent and any additional ingredients that I added to my favorite soap recipe.

final results

Soaps that were made in this tutorial. Left to right: McIntosh Apple (Candle and Bath Supplies), Rebel (Tradewinds), Indian Summer (Tradewinds).


Labels give the finishing touch,
even though they hide the
beautiful swirls.