La Jin's Voice: Part 2: Making Cold-Process Soap (by SpiceySuds)

These are general instructions and general information. Please see the links in this article and in the one I wrote previously for more.

When researching cold-process soap making, you will come across terms that will help if you understand them before making soap. I am going to cover several terms and a post a link to a thorough list.
Glossary of Soap Terms

Additives: Any ingredient added to soap that is not part of the soap itself is considered an additive. Therefore, any ingredient excluding lye, water, and oils/fats/butters are additives. Some examples of additives are colorants, fragrance materials, and preservatives. Additives may include herbs, micas, salt, grapefruit seed extract, excess oils/fats/butters that remain unsaponified, vitamins, clays, etc., (for those that only want to use “Natural” colorants here is a site to check out: Adding Color to Homemade Soap )

Colorants in tote.

Fragrance oils in tote.

-Lye: sodium hydroxide is used for cold process soap. Potassium hydroxide is used to make liquid soap. Lye is a caustic substance, and can and does cause horrible burns. CaseReports (Caution, there is a photo of a caustic burn on a hand at that link that may be disturbing to some people.)

-Saponify/Saponification: the chemical reaction between the lye and fats from the oils that results in glycerin and soap.

-Soap Making Process: Cold Process

Cold process (CP) soap making is the process where lye is dissolved in water to form a solution. The lye-water solution is then added to melted fats and oils and constantly stirred or mixed with a hand blender.

Mixing bowl w-blender, slightly mixed,
after pouring in lye solution.

After trace is detected, scents, herbs, and/or colorants may be added to the soap batter. After trace but before seize, the cold process soap batter is poured into molds.

Molds

More molds.

The molds are usually insulated with blankets or towels. Within 24 hours, the soap batter hardens sufficiently to be removed from the mold and to be sliced into bars. Fresh bars of cold process soap must cure on drying racks for four to six weeks to allow the lye to completely saponify the fats and oils into soap. After four to six weeks of cure, cold process soap should be ready for use and should not contain any lye. This process is referred to as "cold" process soap making because no heat from an external source is added to the soap batter.

-Soda Ash: Soda ash forms when unsaponified lye reacts with naturally occurring carbon dioxide in the air. Soda ash is a harmless, and it's most common on the surface of your cold process soaps, but sometimes soda ash can form throughout the middle of the bars. ... Temperature can also play a factor in soda ash formation.

Soapqueen.com - explaining and preventing soda ash

Soapjam.wordpress.com - removing soda ash efficiently

Trace

Term used to define the moment of cold process and hot process soap making when the soap batter thickens and becomes viscous due to the onset of saponification. Trace is determined when a spoonful of soap batter dribbled back into the soap pot leaves a "trace" and remains visible on the surface. Likewise, trace may be determined when a spoon moved through the soap batter leaves a "trace" or distinguishable trail on the surface of the soap batter.

Many of the soapers on youtube and those that have their own websites or eBooks give their own soap recipes - or you can use soap calculators/lye calculator sites that will help you formulate your own recipe.

On Soapcalc site, under Section 5 “soap qualities and fatty acids,” it lists a few qualities/properties the chosen oils will result in. Iodine is a quality that will show how hard/hardness the soap will be. When you hover the cursor over Iodine on the Soapcalc site, it will show you the numbers 41-70, and the closer you get to 70 the softer your bar will be, and it will dissolve quicker when used. Using a higher amount of coconut oil will get a harder bar, but also may be more drying on the skin. Using a slightly higher superfat percent may help it not be so drying, but it is best not to go above 9 or 10% superfat. Superfat is the percent of oils that will be unsaponified.

I will list three sites that help with formulating soap recipes. Brambleberry’s is the easiest for me when I want to “recalculate” a recipe because if I want to increase my 1lb recipe to a 2lb recipe, all I need to do is put in the figures for my 1lb recipe. At the bottom I use the recalculate to 2lbs, but it is added as 32oz for the oils. It will automatically recalculate the amount of oils as well as lye and water. Distilled water should be used or many, as well as myself, use Aloe Vera juice, though I did use distilled water for the first few months when I began.

Container I used for aloe juice
(which I added after I poured and stirred in the lye),

Soapcalc

Brambleberry

The Sage

To cover a bit more on the utensils that are needed:

An accurate digital scale that will measure in both grams and ounces.
A stick blender/emulsion blender.
Latex/rubber gloves & apron.
Mixing bowls/cups.
Rubber spoons/spatulas/whisks.
Soap mold(s). If you use wood molds you’ll need parchment paper or freezer paper to put in the mold unless you have a silicone liner.

Molds

Utensils in the tote where I store them.

More supplies

When mixing lye, no metal other than stainless steel should be used, and plastic should be strong enough that it won’t melt. I have used cottage cheese containers, or plastic containers from Lowes to mix paint in, or plastic laundry detergent containers. I use a plastic drinking cup to measure the lye into, then pour it into the liquid being used (in the cottage cheese container or other container) and mixed/stirred with a rubber spoon. I then rinse out the plastic cup with warm water. Since lye is a drain cleaner, I rinse the cup well with warm water and then let the water run in the sink/down the drain thoroughly.

Bucket I keep the lye in, sitting by my scale
with a cup I use to dip out the lye.

After choosing a recipe, you can measure your solid oils/butters into a container and your liquid oils in another container (this is what I do but not necessarily the way it must be done). I mix the lye solution first and wait for the temp to come down to around 100-110 degrees, and then I start to melt the hard oils/butters in the microwave.

Pre-measured hard oils and liquid oils.

It seems most soapers like to “soap” at “room” temp and I also like to soap at a lower temp- 90-100 degrees. It does seem to matter what oils you use, as well as how much blending is done. If FO or EO is used each can affect how quickly the batter will thicken.

One Recipe I use is: 32oz batch

Castor oil 2oz

Coconut oil 6oz Distilled water 10.6oz

Olive oil 14oz Lye 4.3oz

Rice Bran oil 5oz

Shea butter 2oz

Sunflower oil 3oz Fragrance oil 2oz

I usually wipe off the spatulas, blender, etc. I use and wipe out the mixing bowls/cups with paper towels and a wet washcloth. Throw away the paper towels. I put the wash cloths and any towels I use in a laundry basket, and wash the next day-it is good to wait a day to wash the dishes and cloths/towels.