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Basic Soapmaking Terms

These are the terms and definitions that a person taking the HSCG Basic Certification exam would be expected to know and understand. Both CP/HP and MP terms are included in the list.

General Soapmaking Knowledge

When an acid dissolves in water, the pH of the solution is less than 7. This solution is considered acidic.
Any ingredient added to soap that is not part of the soap molecule itself. Therefore, lye, water, and saponified oils/fats/butters are not considered additives. Examples of additives are colorants, fragrances, herbs, alcohol, silicon dioxide, and excess oils/fats/butters that remain unsaponified.
When an alkali dissolves in water, the pH of the solution is greater than 7. This solution is considered alkaline. Alkali is a synonym for base.
When a base dissolves in water, the pH of the solution is greater than 7. This solution is considered basic. Base is a synonym for alkali.
The corrosive effect of a chemical on another material or living tissue. Caustic can refer to an acid or a base but is typically used to describe the action of a base.
Cold Process Method (CP).
Soapmaking method where the starting ingredients of lye solution and a blend of oils/fats/butters are separately brought to desired temperatures, mixed together, and allowed to react without additional heat.
Gross Weight.
Total weight of the container and contents.
Hot Process Method (HP).
Soapmaking method where the soap is made as in cold process method but then further cooked using additional heat.
Melt and Pour Method (MP).
Soapmaking method where the MP base is commercially produced and the saponification process is complete. The MP base functional ingredient may be a true soap, a synthetic detergent, or a combination of both. This pre-made MP base is formulated to withstand re-melting so the MP base sets up immediately with no curing or drying time.
Net Weight.
Weight of the contents in a container, not counting the weight of the container or lid.
Refers to the acidity or basicity of a chemical typically dissolved in water. The measurement scale goes from 0 (strongly acidic) to 14 (strongly basic) with pH of 7 representing neutral condition. Alkaline water solutions have pH values higher than 7.0 and acidic water solutions have pH values lower than 7.0. Neutral water has a pH of 7.0.
Weight of an empty vessel or container. The tare weight is subtracted from the gross weight to get the net weight.


Essential Oil.
An undiluted volatile oil extracted from plant matter by distillation, expression, or solvent extraction.
Flash point.
The lowest temperature at which a liquid may be ignited. The ignition source might be a spark, flame, or hot surface.
Fragrance Oil.
A blend of aromatic chemicals, synthetic or natural, that may be diluted with a carrier such as propylene glycol, vegetable oil, or mineral oil.

Safety, Handling, and Environmental

An abbreviation for the Consumer Product Safety Commission (CPSC), an independent US Government agency that protects the public from unreasonable risks of serious injury or death from thousands of types of consumer products under its jurisdiction, including soap.
The abbreviation for the Food and Drug Administration. An agency of Health and Human services charged with the duty to inspect, test, approve, and set safety standards for foods and food additives, drugs, biologics, cosmetics, household and medical devices, veterinary products, tobacco products, and devices that emit radiation.
The abbreviation for the Federal Trade Commission, the US government agency responsible for enforcing the Fair Packaging and Labeling Act, including the “Made in the USA” slogan. The agency also accepts and investigates complaints of fraud in commerce, including non-receipt of items purchased online.
Net or Net Contents.
The amount of product not including the container, which may be required to be stated as weight or as volume, depending upon the product.
The acronym for the National Institute of Standards and Technology, a division of the US Department of Commerce responsible for enforcing laws and regulations regarding product labeling and net weight.
The abbreviation for Safety Data Sheet (previously called Material Safety Data Sheet or MSDS). The sheet contains up to 16 categories of information on the hazardous properties of the material, first aid measures, spill containment and cleanup procedures, disposal considerations, regulatory information, and other important information. The sheets are available from vendors who sell these materials. For each material used by the soapmaker, a SDS should be available for reference by the soapmaker, employees, or emergency responders.
The abbreviation for the United States Department of Agriculture, which regulates animal care products and organic products.
The abbreviation for the United States Department of Transportation, the regulatory agency responsible for enforcing laws regarding the transportation of hazardous chemicals on US interstate highways.

Cold Process and Hot Process Soapmaking

A stable, non-separating suspension of oil in water or water in oil.
A common name for a solution of sodium hydroxide or potassium hydroxide.
Lye Discount.
The amount of sodium hydroxide or potassium hydroxide omitted from a soap recipe in order to ensure an excess of fat or oil.
The process of converting waste animal tissue into stable fat or removing impurities in animal fats with the use of heat. Tallow is a rendered fat.
A chemical reaction between oils or fats and lye to produce glycerin and soap.
Saponification Value (SAP).
The number of milligrams of potassium hydroxide required to completely saponify one gram of fat or oil.
Condition where the soap suddenly becomes too thick to pour into a mold.
The practice of making soap with an excess of fat or oil.
The point at which the soap has become thick enough to pour into the mold without separating and when a spoonful of the mixture, poured back into the bowl, leaves a faint imprint or trail on the surface.

Melt and Pour Soapmaking

White crystals caused by the salt separating from the MP base and forming in or on MP base. Generally caused by improper storage.
Color Migration.
Condition where the colorant in the product bleeds from one layer into another.
Small, pre-crafted items that may be suspended in the MP base to create depth and design within the product.
Glycerin Dew.
Sweating caused when moisture from the air is attracted to the glycerin in the MP base and droplets of moisture appear on the surface of the MP base. It is commonly caused by overheating the MP base, high humidity, or improper soap storage.
Melt Point.
The temperature of the MP base at which it becomes completely liquid.

Updated April 18, 2017

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