Glossary Of Common Soap Making Terms

If you ever find yourself in a bubbly conversation with fellow soap enthusiasts or need to troubleshoot your soap-making adventures, you'll want to have the right words at your sudsy fingertips. It's your passport to the world of safety and soap mastery. 



Alkali : 
A compound / base with a PH of greater than 7. Sodium Hydroxide (lye) Potassium Hydroxide are both considered alkali.

Anhydrous : 

A substance that doesn't contain water.

Antibacterial : 

A substance which can fight bacteria.

Antioxidant : 

In the case of soap making, adding an antioxidant will slow or prevent oxidation, in order to prevent spoilage. 

Antiseptic : 

Substances that reduce skin infection.



Base : 

The alkali used in soap making. Sodium Hydroxide and Potassium Hydroxide are both known as bases.



Carrier Oil :

Plant based oils which are used to dilute essential oils prior to use on skin.

Castile Soap : 

100% olive oil soap, named in honour of a region in Spain from where it originates.

Caustic Potash :

Also known as Potassium Hydroxide. It is the alkali / base used when making liquid soap.

Caustic Soda:

Also known as Sodium Hydroxide or lye. It is the alkali / base used when making bar soap.

Cold Process : 

A method of soap making that relies on heat to melt oils. There is no cooking involved. Fats react with lye water to form soap via a chemical process called saponfication. 

Cosmetic Grade : 

Ingredients approved for cosmetic use in products such as soap, bath and body products and make-up. 

CP : 

Acronym for 'cold process' soap making.


Acronym for 'crock pot hot process'. First the soap is brought to trace and then is cooked in a crock pot.


Acronym for 'cold process/oven process'. Soap is made in the same way as cold process soap making, however, it is then placed in the oven once moulded to force the gel stage.

Cure : 

The time period between making the soap and using it. While curing, new soap completes saponification and excess moisture evaporates out. This creates a harder soap which produces better lather, and is milder. Soap should be left for between four to six weeks before it is used. During this time soap becomes mild and the saponification process completes.



Detergent : 

A synthetic, liquid / water-soluble cleansing substance that acts similarly to soap but is made from chemical compounds, and not fats and lye.

Discount - Lye :

To reduce or to use less. If you are following a lye discounted recipe, you are using less lye than is needed to saponify the entire amount of oils. This ensures that the soap does not contain any free lye and also has extra oils to moisturise the skin. The usual amount of lye that is discounted tends to be around 5% - 10% but some recipes can go as high as 20%. 

Discount - Water : 

To reduce or use less. If the recipe calls for water discounting, you will use less water than the normal amount that is usually considered a safe amount. This safe amount of water is commonly between 36% - 38% percent of the amount of oils used in a recipe. Discounting water is used to produce a harder bar of soap faster, but can lead to seizing. As soap cures, the water evaporates. If you have less water, the soap will be harder at the end of 4 weeks.

DOS : 

Also known as Dreaded Orange Spot, and appears as small orange-beings spots. This phenomenon can occur in soaps with a high percentage of oils that can then later go rancid. 


Embeds : 

Pieces of soap that are embedded into the soap batter during the soap making process.

Emollient : 

A substance such as vegetable oils or glycerine which soften and smooth skin, and retain the skins moisture.

Exfoliant :

 Is a rough additive which when added to soap to remove dead skin cells and dirt from the skin.


Fatty Acids : 

Lauric acid, Myristic acid, Palmitic acid, Stearic acid, Oleic acid, Linoleic acid, Ricinoleic acid and Linolenic acid are all examples of fatty acids. They are compounds of carbon, oxygen and hydrogen found in fats and oils, which can be saturated or unsaturated. Fatty acids give soap a bubbly lather, hardness, stable lathers, cleansing and conditioning characteristics.



Gel Stage :

Once the soap maker has mixed the soap to trace and poured it into the mould it will heat up. The soap is then wrapped and allowed to heat up further to undergo a change. It will then become translucent, and look like vaseline. 

Glycerine : 

Glycerine is a clear, sweet, thick, sticky liquid which is a bi-product of the saponification process. It is natural emollient and humectant. Handmade cold process and hot process soaps retain the glycerine whereas large scale commercial soaps making often removes it for use and sale in cosmetics and replaces it with a cheaper, synthetic version. 

Glycerine Soap : 

Transparent soaps that also has extra glycerine, alcohol and sugar added to it.



Hot Process : 

A method of soap making that requires external heat to speed up the process of saponification. The emphasis here is on the temperature at which saponification takes place. It also reduces the need for a long curing period.


Acronym for 'hot process' soap making.

Humectant : 
A substance that attracts and aids absorption of moisture into the skin.


INCI Name :
Short for the International Nomenclature of Cosmetic Ingredients,  ICNI is an international system of names for waxes, oils, pigments, chemicals, and other ingredients of soaps, and cosmetics, based on scientific names and other Latin and English words. This system enables consumers to identify ingredients that may have an adverse affect on their health.
Insoluble : 
A substance that is incapable of being dissolved. Fats and oils are insoluble in water.


KOH : 
The molecular formula for Potassium Hydroxide.

Litmus paper : 

A paper strip which contains water soluble dyes and is used to determine the pH level of a substance.



Lye : 

Also known as Sodium Hydroxide.

Lye Discount : 

To reduce or use less. In such a recipe, the soap maker uses less lye than is needed to saponify the oils in the recipe. This ensures that the final soap product does not contain any free lye and has extra oils to moisturise the skin.



M & P : 
Short for melt and pour soap bases. It is pre-made soap that can simply be cut up and melted to create soaps. 

Micas : 

a silicate material occuring naturally in certain geological formations that comes in a range of colours and is resistant to heat. 

Milled Soap : 

A commercial process that removes the glycerine from the soap, forms it into pellets, and presses the soap into shape. 

Milled soap is known to lather up better and have a finer consistency. 

Material Safety Data Sheet. Provided by manufacturers which supply raw materials. The sheet discusses data on physical, chemical, environmental characteristics, toxicity, risk and safety information. It is intended to provide workers and emergency personnel with procedures for handling or working with that substance in a safe manner.


NaOH : 

The molecular formula for Sodium Hydroxide.



OHP : 
Short for 'Oven hot process'. Hot process soap making that uses the oven as the heat source.


pH : 

pH is the measure of the acidity or alkalinity of a solution. A substance with a pH value greater than 7.0 (alkaline) are bases; less than 7.0 (acidic) are acids with 7.0 being neutral.

Potassium Hydroxide : 

Also known as Caustic Potash. It is the alkali / base used in liquid soap making.

Preservative :
 A natural or synthetic chemical that is added to prevent decomposition as a result of microbial growth.


Rancidity :
When fats and oils decompose (oxidation of fatty acids), this creates an unpleasant, stale smell.
Re-batching : 
Also known as hand milling. Already made cold process soap is grated, then melted down into a small amount of liquid is applied and with heat until it reaches a translucent stage whereby the  soap is moulded.

Ricing : 

When a fragrance reacts with base oils, it creates what looks like small rice shaped grains in soap batter, like a rice pudding. Warming fragrance oil prior to adding it to the soap base can reduce the chances of this, as well as not discounting water.

Room Temperature Method : 

Instead of using heat to melt hard oils, hot lye solution is used. No thermometers or external heat sources are used.




SAP Value : 
Represents the number of milligrams of potassium hydroxide or sodium hydroxide required to saponify 1 gram of fat.

Saponification : 

Saponification is the chemical reaction between an alkali (lye) and a fat or oil to form soap.

Seize :
This is where something has gone wrong during the soap making process. A rapid solidifying of the soap while still in the soap pan.  It goes from a smooth, liquid to a thick state.
Soda Ash : 
A powdery white residue that can form on the surface of soap. It occurs when un-saponified lye reacts with naturally-occurring carbon dioxide in the air. It is mainly a cosmetic issue, but still soap makers do not like dealing with it.
Sodium Hydroxide : 
Also known as Caustic Soda. It is the alkali / base used in bar soap making.
Soluble : 
Capable of being dissolved or liquefied.

Super-fatted : 

The excess oils left un-saponified in the finished soap. This excess oil contributes to the moisturising qualities of soap.

Surfactant : 

A substance (like soap) that, when dissolved in water, lowers the surface tension of the water and increases the solubility of organic compounds.



Trace : 
The point in soap making where the mixed lye and oils have combined to a thick substance. When drizzled lover the soap mix, a visible trail is left.


Unsaponifiables : 

Oils that do not participate in the saponification process and remain in their natural state in the finished product.