Cold Process Method of Soap Making

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Cold Process Method of Soap Making

These are the molds that I am using for this tutorial. They were, at one time, a 10-foot downspout. I was able to cut 10 molds out of a $4.95 piece of downspout.

These are great for test batches. They each hold a 2-1/2 pound test batch. My molds are numbered because I typically make multiple batches during a soaping day. The mold number is entered on my batch data sheet so that I can keep track of the multiple batches that I make in a day.

To prepare the mold I tape a baggie onto the bottom of the mold with packaging tape that I buy in bulk from the warehouse store. The tape is carefully pressed into the ridges in the mold. If not the raw soap will find its way out of the mold (ask me how I know). I usually prepare my molds the night before so I don’t have to spend the time during my soaping day.

For added stability I set the mold on a towel in a shallow plastic container and tuck the towel around the mold tightly. This also helps keep the soap in as much as possible. Try to keep the towel flat on the bottom of the mold because the finished soap will take the shape of any folds or ridges on the bottom. I’m still searching for something flat to use on the bottom of the mold. Some soap makers insulate their molds, however, when I did the soap became really hot and expanded. When it cooled it contracted and left an empty cavity in the top of the soap.

The Process

Since you will be weighing liquid it is a good idea to protect your scale by placing it in a large baggie. Make sure the feet of the scale are on a solid surface and level.


Measure the distilled water. I chill my water because it prevents the lye/water from reaching 210 degrees. When chilled the temperature rises to only 170 degrees. If you use ¼ distilled water ice cubes the temperature rises to just 150 degrees. This cuts down on the waiting time considerably.


Note: I typically let the lye/water and oils lower to around 120 degrees before combining. Other soapmakers use the 80 degree mark as their mixing temp. and some use a higher mark. You need to find out what is right for you. Try to use the same temp each time you make soap. This eliminates one variable and enables you to produce more consistent batches.

Carefully measure the lye into the plastic bowl. If you pour too much in just spoon out enough until the correct amount remains.

Place the distilled water in the left sink to prevent any major disaster if it should spill. Slowly add the lye to the water and continue stirring until the water becomes clear. If you don’t stir long enough the lye will crystallize on the bottom of the glass measuring cup and will be difficult to remove. So just keep stirring until it becomes clear, it takes about a minute. Be careful not to breathe too deeply at this point. Toxic steam rises during the first couple seconds after the lye is added to the water. At this time I leave the whisk in the lye/water as a reminder.

While waiting for the lye to cool down I weigh out my solid oils. My scale has a tare feature so I can reset the scale to zero between oils. This way I can weigh all of the hard oils in the same container.

Don’t include your superfating nutrient oils at this time. They will be added after trace.

On days that I plan on making multiple test batches using the same base oils I will weigh all of them out in individual bowls at first. This can be done a day ahead and stored in plastic containers with lids. It really cuts down on time during my soaping day and enables me to make more batches on the few days that I am able to designate as soaping days. These are the days when the husband and kids are elsewhere.

There is no need to heat the liquid oils since they don’t need to be melted. They are added after the solid oils are melted and the pan has cooled down a bit. The addition of the liquid oils help lower the temperature of the oils. I haven’t chilled my olive oil yet, however, it might help cool down the oils quicker

The heat has been turned off. There is no need to bring the oils to a boil, as it might deteriorate the oils. You only need to heat them until they almost melted. At this time I place the pan in the right side of my sink to cool. The pan stays in the right sink until the mixture is ready to pour. The location eliminates the possibility of mishaps

The lye/water in the left sink is currently reading about 154 degrees.

Tip: When the can has been emptied using the spout there is still about ¼ cup of oil left in the can. In an attempt to get all the olive oil out of the can use a can opener to open just one corner and pour the remaining oil out of this corner.

Measure out the olive oil and set aside.

While you are waiting for the lye/water and oils to cool you can measure the items that you will be adding after slight trace.

Here I am measuring out shea butter and then I will melt it in the microwave.


To the melted shea butter I add fragrance oils (FO’s) and/or essential oils (EO’s). If my kitchen window is open this is usually the time that the bees start to arrive.

I recently purchased 25 fragrances in 2 ounce bottles so I could make small test batches and determine which ones to add to my line. The 2-ounce size is perfect for a 2-1/2 pound batch (the 2-1/2 pounds typically refers to the weight of the oils in the batch). And this size batch fills up my molds perfectly with only a small amount additional. You’ll see what I do with the excess later.

I prefer making test batches with 2 ounce fragrance oils (FO)/essential oils (EO). Since I purchase my oils over the internet I don’t have the chance to smell them first so I am going by word of mouth or just by the description on the vendor’s web-site (and you know that their descriptions of their products are all soooo enticing). Anyway, I have purchased some fragrances that I really dislike so this way I won’t have a large quantity of left over FO’s and EO’s. I have also discovered that my friends like some of the fragrances that I dislike so before I make a final decision I run the soaps by others to see what the general consensus is. Just because I don’t like the smell doesn’t mean they won’t be a hit.


I also add botanicals and clays to the shea, FO/EO mixture and other liquid nutrient oils such as castor oil or avocado oil.

Colorant is added to the base oils just before adding the lye/water because they will be incorporated during the stirring. The nutrient oils are stirred just enough to incorporate and the colorant wouldn’t be distributed enough. I have attempted to add the colorant to the lye/water, however the lye seems to diminish the color or eliminate it completely.

Stir and set aside covered with saran wrap.

Note: This dish now contains the ingredients that will be added at an early trace. Add the olive oil to the melted solid oils.

Add desired drops of liquid colorant.

I like to add it to my oils because when I use the stick blender it mixes very well.

Place the thermometer in the oils so you can keep track of the temperature. We are aiming for around 120 degrees.

At this time I add silk protein to my lye/water.

I have heard a lot about adding silk protein, but honestly, I don’t really notice that big of a difference. Someday I will make two identical batches except one will contain the silk protein. Then I will be able to determine if it makes a difference. So many other soapmakers are adamant that it is so much better that there must be something to it.

At this time the lye/water is near 120 degrees and the oils are near 120 degrees.

Slowly add the lye/water to the oils while mixing constantly with the whisk.

After all of the lye/water has been added I begin using my stick blender. As it blends you will notice it becoming lighter and lighter. A few bubbles will form on the top.

Keep blending until you reach a light trace, about 1 minute. The soap mixture will have the consistency of very runny pudding. When you lift the stick blender out of the soap mixture it will have a coating of the soap mixture on it.

My superfatting/FO/EO/additive ingredients are handy, and the mold is readily accessible. Next to the tall mold I have a small mold for the ounce or two that will not fit into mold number 2.

The light trace has been reached.

Now I add the superfat mixture of ingredients. Scrape down the sides of the bowl to get all the goodies in your soap.

At this time I incorporate the superfat mixture using the whisk. This process also brings the mixture to a more firm trace. This step also helps to minimize the amount of air bubbles that the stick blender seems to add to the soap

Here is an excellent picture of trace. You can see how the whisk left an impression on the top of the soap when removed.

At this time the soap will begin to firm up very quickly so you need to move fast. I usually stir with the whisk while lifting the pot up out of the sink to pour the mixture into the mold.


Carefully pour the soap into the mold.

Certain fragrance oils will tend to seize a batch. If the batch seizes it becomes difficult if not impossible to pour so it is also a good idea to have a flat box mold lined and available in the event that your batch seizes and you need to get it out as quickly as possible. A seized batch is still a good batch it just comes out looking a little rough. I have used seized batches for hand formed bars and was very pleased with the results. Seized soap can also be grated and added to other batches to make confetti soap. Sometimes you need to be creative in order to save a batch.


This bar of soap is my favorite. It includes a little bit from each batch. Just make sure the fragrances are complimentary. It is an excellent bath bar or kitchen sink bar. It is a good idea to have several of these molds ready. One for florals, one for herbals, etc. The wrong combination can really make for a stinky bar.

The additional soap is added to a small plastic mold. Scrape the sides down to get all the soap into the mold.

Cover the soap with saran wrap to prevent soda ash from forming.

Soda ash is a white powder that forms on the exposed surface of the soap when it cures. It is oxidation that is harmless, but can be sliced off if you are going to sell the bars. It washes off during the first couple uses.


Here are the batches that I made today. I ended up making 10 on this soaping day. You can see a small amount of expansion in mold number 8. As it recedes it leaves a concave top that needs to be sliced off to even it up.

The soap rests for 24 hours before I remove it from the molds and slice it. To remove the soap from the molds I first place it in the freezer for about 3 hours. Then I take it out of the freezer and let it sit for 5 minutes. The soap typically slides right out, however sometimes I need to use a little bit of force. If it does not come out easily I place the soap over an empty mold and push it through. Once it starts sliding into the empty mold I lift it off the empty mold and pull it out. I then let the soap warm to room temperature and dry off before cutting.

This is my soap cutter. I attended a local soapmaker gathering where a fellow soapmaker donated this cutter for one of the door prizes. I can’t believe how fortunate I was to win because I never win anything. It must weigh 40 pounds though. The wire that cuts the soap is a piano wire.

Since the cutter is so heavy I designed my soap cabinet with this in mind. I placed it in such a way that I can cut the soap while it’s in the cabinet.

This is one of my soap cabinets. The first shelf I added was the one for my soap cutter so it was at the ideal height for me. I left just enough room at the top so I could grasp the metal bar without scraping my knuckles. I never have to move it now except to clean up the soap crumbs that accumulate underneath it periodically.

I then decided what I wanted on the other shelves and spaced them accordingly. This unit is for my dry ingredients, packaging supplies and equipment. I have another smaller unit to the left of this one for oils and FO’s and EO’s. Plus I have stashed stuff in 5 other locations.


As I slice the soap I place it into my drying rack.

This is really a hot tip. I get these from the nursery. They are actually flats that the plants are sitting in. The nursery throws them away and I am able to take as many as I need. You just need to clean them really well. One of mine had a slug sleeping in it (I left him at the nursery though). They are a bit flimsy so you can double or triple up on them depending on how high you stack them.


This is what they look like all stacked up. I typically cover them with fabric so they don’t get dusty while they are curing.

The racks on the bottom need more strength than the ones on the top. Here the bottom racks are 3 flats each then the top racks are 2 flats each.


To finish my bars I wrap them with a band and attach the label with double-sided tape. The shape of these bars makes them difficult to wrap. I typically wrap them just before selling them because they continue to loose water and if I wrap them to soon the bands tend to slip off. The reverse of the label contains the ingredient information and my web-site address.

They are rustic looking, but perfectly sliced.




One thought on “Cold Process Method of Soap Making”

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