MASTER THE BASICS – SOAP TERMINOLOGY

There are hundreds of terms used in soap making, we have compiled an alphabetical list below to ease the understanding of some of the terms you will come across in our recipes and information. If there are any terms that is unclear, please do let us know.


K –

KOH: The molecular formula for Potassium Hydroxide.


L –

Lard:  Fat that has been rendered from pigs (hogs).

Litmus paper: A strip of paper containing a mixture of water-soluble dyes that is used to indicate the pH level of a substance.

Lye: Another name for Sodium Hydroxide.

Lye Discount: The word discount in this context means ‘to reduce or use less’.


M –


Milled Soap:  
A commercial process that removes the glycerine from the soap, forms it into pellets, adds fragrance, and presses the soap into shape. A home soap maker can hand mill (re-batch) soap by grating it up, adding a small amount of liquid and applying heat until it reaches a translucent stage at which time the fragrance is added and the soap is moulded.

MSDS: Material Safety Data Sheet. A form containing data regarding the properties of a particular substance and is intended to provide workers and emergency personnel with procedures for handling or working with that substance in a safe manner.

M & P:Refers to melt and pour soap bases. Pre-made soap that can easily be cut up and melted to create decorative soaps. Contains lye like all soaps do and is available in various

Melting Point:The temperature at which a solid substance (oil for soap making) melts.


N –

NaOH: The molecular formula for Sodium Hydroxide.

Natural: A material that does not contain any synthetic substances.

Nutrient: In soap making, a substance that contains properties that are beneficial for the skin.


O –

OHP: Acronym for ‘Oven hot process’. Hot process soap making that uses the oven as the heat source.

Organic: A substance that at one time was alive and has not had chemicals or synthetic materials introduced to it.


P –

pHpH 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.

Photosensitizers: Substances that can cause skin to be more prone to sunburn when exposed to sunlight.

Potassium Hydroxide: Potassium Hydroxide is another name for Caustic Potash. It is the alkali (base) used in liquid soap making.

Preservative: A preservative is a natural or synthetic chemical that is added to products to prevent decomposition by microbial growth.


R –

Rancidity: Having an unpleasant, stale smell, as through decomposition, especially of fats and oils.

Refined Oils: Fats and oils that have had impurities filtered out.o.

Rendered: Beef fat that has been heated and melted down to remove all impurities is said to have been ‘rendered’.

RTCP: Acronym for ‘room temperature cold process’ soap making. The fats and oils are at room temperature when the lye solution is added.

Ricing: Ricing occurs when a fragrance oil reacts with your base oils and produces little rice shaped grains in your soap batter. The soap batter will resemble rice pudding. When using a new fragrance, do not discount the water in your recipe and warm the fragrance oil (while still in its bottle) in a warm water bath before using it.

Re-batchingAlso referred to as hand milling. A home soap maker can hand mill (re-batch) soap by grating it up, adding a small amount of liquid and applying heat until it reaches a translucent stage at which time the fragrance is added and the soap is moulded.

Room Temperature Method: A soap making method similar to the cold process method. Instead of using heat to melt hard oils, the hot lye solution is used instead. No thermometers or external heat sources required.


S –

Separation: Separation in soap making can happen in a couple of ways. In your soap pot right after adding in a fragrance or essential oil. The soap is reacting to the fragrance or essential oil and the soap batter will resemble apple sauce. It can also happen in your soap mould if you pour the soap into the mould before it has reached a true trace. This will look like a layer of liquid oil on top of the soap.

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.

Sebum: The fatty substance secreted by the sebaceous glands of mammals that protects and lubricates the skin and hair.

Seize: A rapid solidifying of the soap while still in the soap pan. Usually caused by high amounts of stearic or palmitic acid, waxes or by some fragrance & essential oils.

Soap: The result of a chemical reaction between a lye solution (sodium hydroxide for bar soap or potassium hydroxide for liquid soap) and fats/oils. If it isn’t made with lye, it isn’t soap.

Soap on a stick: A really bad case of soap seizure while trying to stir!

Soda Ash: A powdery white residue that sometimes forms on the surface of soap. Can be drying to the skin but is easily wiped off of the bar of soap with a damp cloth..

Sodium Hydroxide: Sodium Hydroxide (lye) is another name for Caustic Soda. It is the alkali (base) used in bar soap making.

Solvent Extraction: The process used to separate botanical matter from essential oils using solvents.

Steam Distillation: The process used to separate botanical matter from essential oils using steam.

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.

Soluble: Capable of being dissolved or liquefied.

Synthetic: A substance made by an non-natural, or chemical, process.


T –

Tallow: The fatty tissue or suet of animals (horse, cow and sheep).

Tocopherols: Any of a group of closely related, fat-soluble alcohols that are types of vitamin E, especially alpha-tocopherol.

Trace: The point in soap making where the mixed lye and oils have combined to a thick pudding like substance. When drizzled on to itself, a trail is left.


U –

UnsaponifiablesThe portion of oils that do not participate in the saponification process and remain in their natural state in the finished product.


V –

Vegan: Not containing any animal parts or ingredients produced by animals.

Viscosity: The resistance of a substance to flow. Honey is more viscous than water.

Volatile Oils: Oils that evaporate rapidly.