Cold Process Soap Making – Frequently Asked Questions - Wholesale Supplies Plus
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Cold Process Soap Making – Frequently Asked Questions

This article answers questions related to the cold process method of soap making.

CP (Cold Process) Soap Making – General Questions

What is CP Soap?
CP Soap is the short abbreviation for Cold Process Soap. This is soap that is handmade and produced, through the saponification process.

What is Saponification?
“Saponification” is the name given to the chemical reaction by which an alkali (usually sodium hydroxide - also called caustic soda or lye) reacts with fats and oils to make soap.

Does CP Soap Contain Glycerin?
Glycerin is a clear, slightly sticky chemical which is a byproduct of saponification therefore it exists naturally in CP Soap.

If CP Soap is made with lye, will it hurt my skin?
Soap is a result of a chemical reaction between lye, fat and water. In 24hrs, you no longer have lye, fat and water - you have soap! If you followed the recipe and proper soapmaking procedures, you won't have any lye at all in your finished soap.

Is CP Soap dangerous to make?
Making CP soap is a bit like driving a car, in that you are working with something powerful, and need to be safety-conscious in order to avoid injury. Make sure that you read up on appropriate safety procedures before starting to make soap, and that you work with appropriate safety equipment, including goggles, an apron, gloves, and something (like vinegar) to neutralize any spills. You should make sure that you are working uninteruppted, can concentrate on what you are doing, and don't have any pets/children around who might distract you or harm themselves or you.

What is a lye volcano?
You should also take care to always add LYE TO WATER rather than pouring water into lye which can result in a lye explosion…sometimes called a lye volcano!

Using a candy thermometer while soapmaking is helpful, too, both to get good results and avoid issues like false trace (explained later in this FAQ), and to ensure that you don't overheat the soap or lye water and create a dangerous mixture. Finally, you should make sure that you are working uninteruppted, can concentrate on what you are doing, and don't have any pets/children around who might distract you or harm themselves or you.

Who regulates CP Soap?
The FDA regulates cleansing agents. They have a very specific exemption for soap that meets certain criteria. The exemption applies to most cold process soap. Our video titled “Cosmetic, Drug or Soap?” addresses this issue. If a bar of soap meets the exemption criteria, the Consumer Product Safety Commission (CPSC) regulates the product.

What are the most common oils used in making CP Soap?
Many soapmakers start out using Crisco to make their first "beginner" soaps, as it is inexpensive, easily obtained and easy to work with. It produces a hard, white bar with stable, cleansing lather. 

In everyday soapmaking, many soapmakers use a lot of palm and coconut oils, as they saponify quickly, produce excellent lather and cleansing power when saponified. They both make a nice hard, white bar of soap. Castor oil is commonly used, as it produces great lather and is conditioning. Olive oil is a favorite because it is makes a conditioning bar of soap. It does not produce much lather, and is not as cleansing as palm/coconut oil when saponified – so, it is often combined in a recipe with palm and/or coconut oil. Some soapmakers choose to make castille soap, which is 100% olive oil soap.

What is trace?
Trace is the term given to the stage of soap making when the ingredients are fully mixed and ready for additives and pouring into molds. This is the goal you are working to achieve when blending your lye water and oils! At the end of the mixing process, you will notice that the ingredients begin to “come together” and resemble vanilla pudding. When it reaches this point and when it is thick enough that dripping some of the mixture across the top of the mixture leaves a trail of drips (and doesn't immediately sink back into the batch), you have reached trace! At this stage, you can start adding in your fragrances, essential oils, colours, and other ingredients which you have set aside to "add at trace", and then put the soap into your mold.

My CP Soap is hard after two weeks. Can I go ahead and use it now? 
It can be really tempting to use the soap at this point – but, it is best to wait!! While oils saponify at different speeds, even those which saponify the fastest (which are generally saturated oils which are solid at room temperature - such as coconut and palm oils) will not be fully saponified after two weeks. Those oils which saponify the most slowly – like olive oil – will still need another MONTH to saponify at that point – they can take up to six weeks to fully saponify. 

If you use the soap too early, it may still contain active lye in the soap. Active lye that has not been saponified is dangerous because it can burn or irritate the skin. If you use the soap too early, it won't have achieved its full moisturizing and cleansing potential. It will be softer than it will be when fully cured. So, you will waste a lot of it, as it will dissolve too readily in water and go down the drain.

Can using a stick blender hurt my CP soap? 
Stick blenders are a valuable tool, and many soapmakers consider their invention to be one of the best things ever to happen to the soapmaking process. However, it is best to use them with a bit of moderation - both to avoid "false trace" (discussed later in this FAQ) and to avoid burning out the stick blender. "Pulsing" the stick blender in short bursts (thirty seconds on, five seconds off, etc.) rather than running it continuously helps your stick blender to last longer, as it keeps the motor from overheating. Also, it helps to avoid false trace, as it keeps the soap from overheating and it gives you a chance to let it settle and observe how close it is to achieving trace. Some fragrances that tend to accelerate trace, will actually seize the soap when used with a stick blender.

What is seizing?
Seizing is when you incorporate additives into your mixture and the soap overreacts by immediately going to trace, becomes grainy and/or becomes hard. Most often it is the result of difficult fragrance oils…but there can be other reasons. Too high or too low temperature can cause the fragrance oil and/or essential oil to overreact, causing the soap to harden suddenly and unexpectedly. Heat produced from a stick blender can often push a difficult fragrance over the edge and cause a seize. It can also be caused by ingredients such as sugars, waxes, jojoba oil, stearic acid, and alcohols. Some base oils such as neem oil, shea butter and sometimes castor oil can also cause soap to seize if used at more than 5%. Additionally, some essential oils (especially cinnamon and clove) can accelerate trace or cause soap to seize. Many Soapmakers avoid seizing problems with fragrance oils by blending them into a small amount of warm oils, taken from your soap pot before you have added your lye solution, and add at early trace.

My soap seized. Is there any way to salvage the soap?
If this happens, first take a deep breath…all is not lost! Your basic soap should be fine to use, just not as pretty as you planned for it to be. Try scooping your soap into your mold and then press it down with the back of your spoon. 

If the seizing is really bad (where the soap has gone virtually solid in your pot) you can try to rebatch the soap by further heating it right away in a crock pot. In this case, most add a bit of added liquid like some milk or cream. 

In general, seized soap can still be used, but some seizes create such a reaction that they might compromise correct saponification.

Why do people talk about curing soap?
Soap is the result of a chemical interaction in which lye (in water) acts upon fat, oils, and nut butters to convert them into soap. This process takes time - the soap is only about half saponified when you have brought it to trace and put it into your mold. How much additional time it will take from that point until it is fully cured and ready to use depends on the oils used. More saturated oils (like coconut and palm oils which are solid at room temperature) tend to saponify more quickly than less saturated oils such as olive oil. Your soap can take anywhere from three to eight weeks to cure, and is only ready for use when it is fully cured.

I want to have a book on hand for CP soap. Is there one you would recommend?
The books by Susan Miller Cavitch are wonderful; many soapmakers swear by “The Soapmaker's Companion”. Also, Essentially Soap by Dr. Robert S. McDaniel is a great book, which gives a lot of technical information about soapmaking which other books do not contain.

My CP soap has this white stuff on the top. Is it the start of mold or something else?
That white powder is called soda ash. Soda ash frequently forms on the surface of the soap and is quite harmless. To get rid of it, scrape, cut or wash off the powder on the soap before use. It does not affect the quality of your cold process soap. 

Soda ash is more likely to appear on soaps that have been mixed and poured either too hot or cold, or not insulated properly after pouring, so that the temperature either drops or spikes to quickly during your gel phase. Soda ash is also more common in soaps containing milk or sugars.

I heard of a person that added chunks of MP soap base to their CP soap base. Can this really be done? Why did they do it?
Sure – and it can look absolutely gorgeous! The trick to doing this successfully is to get good adhesion, and spritzing the MP pieces with some rubbing alcohol immediately prior to adding them helps a LOT with good adhesion. Also, it's critical to not melt the MP soap base pieces, if you want them to stand out and look distinct from the CP around them. The best way to avoid melting the MP is to add it to the CP at trace – perhaps gently pushing the MP chunks into the very top surface of the CP in the mold, so that they are exposed to less heat than when fully surrounded by CP. Also, it helps to not insulate the finished soap during saponification.

How can I harden my bar of cp soap?
One of the best ways to create a hard bar of CP soap is to plan your recipe to incorporate oils which create a hard bar when saponified. For instance, coconut and palm oils contribute to producing a hard bar of soap – although they are best combined in a recipe with other oils such as olive, sweet almond, etc. which will boost the moisturizing properties of the soap. (A bar made of just coconut and palm oils will tend to be so hard that it borders on being brittle, and so cleansing that it can dry out your skin). 

There are also additives that can be used in CP to produce a harder bar - like stearic acid and sodium lactate. Make sure to follow the Wholesale Supplies Plus usage guidelines when adding these to your soap. You do not want to add too much or have poor incorporation of your additives!

Why do people add Sodium Lactate to CP soap?
Sodium lacatate is thought to harden cold process soap while minimizing shrinkage associated with curing.

When my soap is ready to use, what is the ideal pH of my soap?
Cold process soap is naturally alkaline. It is normal for soap to have a pH between 8 and 10.5. Industrial made soap has an average pH of 10.5, while the pH of quality handmade soap can be as low as 8.5.

How can I test the pH of my soap?
There are three ways to check the pH of your soap.
  1. pH strips. Special pH strips give you an immediate indication of the pH.
  2. Use testing. For this, you simply wash your hands with your soap. Soap with an acceptable pH will rinse clean and will leave your skin smooth and refreshed. If your lather instead feels slimy, difficult to rinse and leaves your hands with a reddened appearance (similar to doing dishes in hot water for too long) then your soap is most likely lye heavy and has not fully saponified. If your soap passes hand testing satisfactorily you may want to test further on more delicate skin such as the inside of your elbows before giving it the final approval.
  3. Tongue test. Some soapmakers also do “tongue testing” or “zap testing”. With this method, you touch the finished bar of soap with your tongue. If the soap causes the tongue to tingle a bit (like touching the tongue to a battery), then there is still active lye in it and it should not yet be used on the skin.

My soap is fully cured but still has a high pH. What can I do?
If your cold process soap has already completed its cure and is still lye heavy, it can generally be saved by rebatching it - perhaps with a high fat liquid such as heavy cream which will give any loose lye some fat to saponify. If your soap gives you a burning or itching feeling while hand testing chances are it is too caustic to be used on the skin, and will only be usable for laundry soap.

Help! My soap turned grainy and got hard when I added fragrance. Why?
Factors which can cause this include too high or too low a mixing temperature, as well as overreaction to your fragrance oil and/or essential oil. Your basic soap should be fine to use, but just not as pretty as it would otherwise be.

Help! My soap separated after I poured it into the mold? Why?
This is probably “false trace”. Sometimes, if your soap is too warm and you work too quickly, you achieve what is called “false trace”. False trace is where the soap looks like it is at trace, but it has not reacted enough to stay together when put in the mold. One way to avoid separation is to mix the soap at somewhat above room temperature and not work too rapidly to bring it to trace. If you take your time bringing the soap to trace and avoid high temperatures and excessive mixing (perhaps pulse your stick blender or hand stir, rather than running it constantly in the batch) you are much less likely to have false trace and soap separation. 

You can attempt to fix the separation by placing your cold process soap mixture back in your soap pot and reheating while stirring until it traces again. Next time you make this soap check your starting temperatures.


What are some exfoliants which can be used in CP?
Exfoliants are materials that remove dead skin cells when rubbed on the skin. Exfoliating materials are available is varying degrees of harshness, depending on your requirements. Some examples of exfoliants that are used in CP soap are: 

Rolled Oats, Oatmeal, Oat Bran, Oat Flour, or Corn Meal 
Apricot, Raspberry, Blueberry Crushed Seeds 
Calendula, Lavender, Rose Flower Petals 
Peppermint, Tea, Sea Kelp Crushed Leaves 
Jojoba Beads

What is the best way to add powdered goats milk to my CP soap?
Many soapmakers add the powdered goats milk to their CP soap at trace and thoroughly incorporate it at that stage, to avoid problems with their soap overheating (described below).

What is the best way to add liquid goats milk to my CP soap?
Liquid goats milk can cause the saponification process to significantly heat up, which can cause the soap to seize, overflow from molds, and brown. In order to try to avoid these problems, many soapmakers chill their liquid goats milk until it is "slushy" and near freezing. Then they add their slushy goats milk to their lye water before combining with oils. Also, most soap makers that use liquid goats milk generally do not insulate the goats milk soaps….this is an attempt to offset the extra heating caused by using goats milk.

Is there anything special I need to do if I want to use honey in my soap?
Honey is similar to liquid goats milk. It can cause the saponification process to significantly heat up. Most soap makers avoid insulating soaps containing honey.

I want to add oatmeal to my cp soap. Can you tell me the best method?
This depends on the look and feel you are trying to achieve! If you want your soap to really show the oatmeal and be somewhat scrubby, you will want to leave the cut oats unground, and pour them across the very top of your traced soap in the mold. Push them down a bit to create depth in the bar. 

If you want the soap to be minimally scrubby and have oatmeal throughout, you will want to grind it in a coffee grinder (or buy colloidal oatmeal, which is VERY finely ground). At trace, incorporate the ground oatmeal into the soap mixture and then pour that in the mold.

What oils are used in a bar of castille soap?
Castille soap is traditionally 100% olive oil. You may find that some soapmakers use the term for soap made primarily of olive oil with some other oils, often coconut or palm oils that increase hardness and lather.

Which oils produce which properties in a bar of CP soap?
There is an excellent reference chart of oil properties when saponified in the WSP Learning Library. Click HERE to view the chart.


What is color "morphing", and what are the best colors to use when making cp soap? 
CP Soap has a very high pH while it undergoes saponification. This high pH can cause many colors to "morph" and change color. While some soapmakers enjoy the unpredictable nature of CP soap coloring, many others prefer to be able to accurately predict the final color of their soap. Colors such as ultramarines and oxides most often produce quite predictable final colors. Natural botanicals (such as alkanet root, beet juice, etc.) produce unpredictable shades which can even vary from batch to batch of the same soapmaking recipe. Synthetic colorants (like FD&C; colourants) are not used because the high pH turns the FD&C; colors brown.

I would like a list of the most common colors that morph into new colors in cp soap, and botanicals I can use as colorants?
Blue tends to be by far the most pH sensitive of the colorants and botanicals which produce shades of blue (such as alkanet root) tend to be quite pH sensitive as well. Other botanicals are more predictable - you might want to experiment with annatto seed, turmeric and calendula petals to produce shades of yellow and orange, liquid chlorophyll to produce shades of green, unsweetened cocoa for brown, madder root for pink/red, paprika for peach, and saffron for a beautiful bright yellow.

Can I use fabric dye to color cp soap?
It is highly recommended that you only use FDA approved cosmetic color additives in soap and cosmetics. Soap has an exemption from the FDA color additive rule but that does not mean you can use anything to color your soap. Soap meeting this definition and exemption, falls under the Consumer Product Safety Commission rules. In the event of a problem, the CPSC will likely say that the FDA has established safety guidelines for color additives in skincare products. It has been implied and frankly it makes sense that the CPSC allows GRAS (Generally Recognized As Safe) products to produce color. An example of GRAS color would be cocoa powder. Fabric dye does not fall into that category.

Mica can sparkle brilliantly, especially in a transparent soap medium like clear M&P.; In an opaque soap like CP, they tend to have a soft, frosted appearance. Some micas migrate while others do not. 

We have a great video that discusses each of these types of colors. Click Here to view Color Additives Video.

How are Iron Oxides, Pigments, Dyes, Lakes, and Mica Colors different?
Iron Oxides (sometimes called pigments) are generally considered to be all natural and will not migrate in soap. They tend to be very dull and earth like in color. The red tends to be more of a brick red and the yellow more of a mustard yellow. 

Dyes are water based colors. They are bright and vibrant. They look much like stained glass on a church window. They will always migrate in mp soap. They are the only color that allows a clear bar of soap to stay clear. 

Lakes are dyes that have been processed with aluminum, barium or calcium. They are bright colors that, when used in moderation, will not migrate in mp soap base. 

How do I know if I used too much color in my cp soap?
If your soap bubbles are the color of your soap, you have used too much color. Your soap bubbles should always be white.

Fragrance and Essential Oils

What does EO mean?
EO is a common abbreviation for Essential Oil.

What does FO mean?
FO is a common soap making abbreviation for Fragrance Oil.

Can all fragrances be used in soap making?
In most cases, fragrance oils can be used in soapmaking. If a fragrance contains a high percentage of alcohol, it will cause cold process soap to seize. Some fragrance oil ingredients may cause melt and pour soap to cloud. Above all, the fragrance oil ingredients need to be RIFM approved for skin contact.

What are Essential Oils and Fragrance Oils and how do they differ?
An essential oil is "natural" - it is derived from a fruit, leaf, root, stem and/or flower. It can be steam distilled or cold pressed. Some companies use solvents to extract their oils. An essential oil’s description will tell you the country of origin and the extraction process.

Fragrance Oils can be a mixture or combination of mixtures of natural and synthetic materials. Synthetic ingredients are manufactured through chemical process. They are "man made".

Are EO's safer than FO's?
Not necessarily. Since EO's are all natural and not chemically manipulated, they may not be as stable in some applications. You will also find that if someone has an allergy to a certain plant, the reaction may be exaggerated with the essential oil since it is a concentrated form of the plant material.

Are all fragrance oils water clear?
No, fragrances can vary greatly in color. They can be dark brown, amber, yellow, orange, green, clear. The color is related to the combined ingredients.

Can all fragrances be used in soap making?
In most cases, fragrance oils can be used in soapmaking. If a fragrance contains a high percentage of alcohol, it will cause cold process soap to seize. Some fragrance oil ingredients may cause melt and pour soap to cloud. Above all, you must follow the fragrance “maximum use level” as this will greatly decrease your liability in the event of a skin reaction.

Can any fragrance oil be used in any application?
You really want to use a fragrance that has been approved and formulated for your specific application. For example, oil based fragrances will float in a linen spray. Candle fragrances may contain ingredients that are not approved for skincare products. Following a particular fragrance oil’s guidelines will help protect you from liability claims.

Can I blend my own fragrance oils?
Yes! This is a great idea and allows you to have a scent that is 100% all your own. To blend your own scent, gather several plastic droppers and paper towels. Drop different fragrances next to each other on the paper towel. Allow the towel to sit for 1 hour. Take the towel to another room and this is how your blend will smell. Using this technique will save you money because it allows you to tweak your blend without using large amounts of fragrance oil.

How do trademarks pertain to fragrance names?
A trademark can protect words, names, symbols, or colors that distinguish goods and services from those manufactured or sold by others. Trademarks are granted and managed by the federal government. When an applicant applies for a trademark, they must specify a classification category or categories. For example, a fragrance name can be trademarked for a finished candle, lotion, soap, etc. When buying a "type" or "compared to" fragrance oil you are taking the responsibility to know if your final product will infringe on a trademark. You can search active trademarks by going to It is illegal to create consumer confusion by naming a product with a name previously trademarked. It is legal to compare your product to another product.

How much fragrance do I use in CP soap?
The amount of fragrance oil will vary from scent to scent. Each of our fragrance oils have a maximum use level assigned, which is listed under the fragrance's listing on the WSP Website. This is based on the ingredients in the fragrance. It is important that you follow this as it will decrease your liability in the event of an allergic reaction. Typically, most people use 6-9% fragrance in CP Soap (assuming the scent has a maximum use level of 6-9%).

I want to know the specific ingredients of my FO.
Fragrance oil formulas are proprietary. This means that the specific formula and ingredients are the property of the fragrance manufacturer and do not legally need to be disclosed to the public. Most companies will not disclose them because they do not want another manufacturer duplicating them.

What are "Extreme" fragrance oils?
There are many terms that have popped up over the last few years. They include, among others "Extreme Concentrates", "Manufacturers Grade", and "Perfumers Grade". These are terms not generally recognized by the flavor and fragrance industry. They are terms that have been utilized by on-line distributors in attempt to explain different fragrance dilution percentages and price structures.

What does flash point mean?
Every flammable liquid has a vapor pressure, which is a function of that liquid's temperature. As the vapor pressure increases, the concentration of evaporated flammable liquid in the air increases. The flash point is the minimum temperature at which there is enough evaporated fuel in the air to start combustion. The fire point of a liquid is the temperature at which it will continue to burn after ignition for at least 5 seconds.

Why is flashpoint significant?
The department of transportation requires that the flashpoint be listed on each bottle. It is important for employee and environmental safety. Any product with a flashpoint under 100º F cannot be transported by ground without a hazardous materials certificate. Any product with a flashpoint under 141º F cannot be transported by air without a hazardous materials certificate because of the change in air pressure involved with flying. Products with a flashpoint of 142º F and higher can be transported by ground and air. If you are working in a commercial facility, most fire departments will want to know the flashpoint of the products you are using. This helps them better be prepared in the event of a fire.

Does flashpoint impact a scent’s aroma?
Aromas with a lower flashpoint often smell stronger because they “lift” into the air faster. Scents with a lower flashpoint should be added to a product at the lowest possible temperature as this helps prevent evaporation. As soon as a scent combines with a base, the molecules in that base will naturally prevent the aroma from further evaporating….instead the scent will come out during the product use.

Who is RIFM?
RIFM stands for the Research Institute of Fragrance Materials. This agency performs independent testing to see if the ingredients that go into fragrance oil produce allergic reactions. They make recommendations on what levels these ingredients should be used in products. They list and "delist" ingredients each December based on their research. Manufacturers follow their studies closely.

Who is IFRA?
IFRA stands for the International Fragrance Association. They are the official representative body of the fragrance industry worldwide. Its main purpose is to ensure the safety of fragrance materials through a dedicated science program. This focus is on fragrance safety helps both the consumer and the environment. Reputable manufacturers follow their recommendations closely. They work hand in hand with RIFM.

Why are some fragrance oils so expensive?
A well formulated fragrance contains balanced top, middle and base notes. This balance provides a complexity and character to the scent. The depth and complexity of a fragrance affects the price of the oil. Sometimes a fragrance formula requires deep base notes that are actually essential oils. These are often more expensive. Substituting them for less expensive synthetic ingredients can produce a fake backdrop to the aroma. Oils can be formulated to different price points. Some oils on the market are “cost reduced” which often this means “diluting” the original formula. Wholesale Supplies Plus does not have expensive formulas diluted. Instead, we encourage customers to use a lesser amount of a good, more expensive oil.

Why are some fragrances stronger than others? 
A good fragrance has a blended aroma of top, middle and bottom notes. Fragrances can smell strong out of the bottle but not perform because they are "top heavy" and lack the depth that your nose cannot detect. On the other hand, a fragrance can smell less than impressive out of the bottle but perform wonderfully because it is well balanced.

Why do some fragrances discolor a product?
Fragrances have ingredients and some of those ingredients have a natural color.

Why do some fragrances turn brown?
Vanilla based fragrances will always turn color...the more vanilla, the more likely the soap will eventually turn dark brown. The color change can occur from days to weeks to months. It is most often associated with the vanilla level in the fragrance oil. It is an inherent property of the vanilla. We developed a product called Crafter's Choice Vanilla Color Stabilizer. This product is added to MP Soap and it will stop a vanilla fragrance from turning brown. It does not work in CP or HP Soap.

Package and Labeling

Do I have to wrap my CP Soap in an airtight wrap?
CP Soap needs to "breathe" and is best stored with exposure to air. Suggestions include a cigar band, breathable fabric, an organza bag or soap box, etc. Some soapmakers find that their soap can get handled a lot and look "shopworn" . In this case, they put plastic wrap around the soap and poke holes in the plastic wrap to allow air to get in.

What is a cigar band?
A cigar band is a strip of paper wrapped around the center of the soap bar both to protect the soap and to give a place for the front and back labels of the soap to be applied. Many soapmakers use home computer word processing programs to be a great way to make cigar bands for their soaps. They look great printed on natural kraft paper.

What is a soap box?
WSP sells some lovely soap boxes! Click Here to view. These are basically pre-folded cardboard boxes which allow the soapmaker to package their soap by putting it in the box and adding a label. The result is a professional looking package which protects their soap while still allowing air to circulate around it and which also allows the customer to smell the soap's scent.

How do I label my cp soap?
The Consumer Product Safety Commission requires:

1. Product name with the word “Soap”. 
2. Net weight of product 
3. Business name and address. 
4. Any applicable warning statements such as “For External Use Only”.

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