Soap making terms can be confusing! Even the best dictionary won’t give you a clear answer. So we’ve made a list of many of those definitions to give you the inside scoop on professional soap terms.

Acid
This isn’t as scary as it sounds! Acid is just a scientific term to describe something with a pH level less than 7. For example, vinegar or citrus fruits are considered an acid, but some can be more harmful and damaging to the skin, like battery acid which is a 0. Also known as acidic.

Additive
Substances such as color, fragrance, or exfoliants that alter the appearance of the final product and are added after the saponification process is complete. In some cases, oils and butters can be used to create a more moisturizing bar.

Alkali-salts
Fatty acids that have been neutralized with an alkali base, like lye.

Base
The scientific term to describe something with a pH level greater than 7. Also known as alkali and basic.

Bloom
A white film that forms on the surface of melt and pour soap if it becomes too dry.

Chelating Agent
A compound that binds to dissolved metals. In soap, this is useful if you have hard water. This will keep the heavy metals from getting into skin and allow them to wash away easily.

Detergent
A synthetic cleansing agent, similar to soap, composed of surfactants that help remove dirt without creating “soap scum.”

Emulsifier
Used to help oil and water stay mixed. A helpful ingredient in soap because the oils pick up dirt and the water washes it away.

Exfoliation
The process of using an abrasive, such as oatmeal, to improve the removal of dead skin cells, creating smoother skin.

Fatty Acid
The building blocks of oil and fats. Common types are palmitic acid, stearic acid, oleic acid, or linoleic acid.

Humectant
A substance that helps pull water from the air to increase moisturizing properties. In soap, glycerine is most common.

Lift
Refers to the strength or weakness of fragrance in a finished bar of soap. Good lift indicates the strength is very good and lasts. Poor lift means the fragrance is either very subtle or does not last once the soap is complete.

Melt Point
The temperature at which a solid becomes a liquid.

Opaque
Light cannot pass through. For example, a wall.

pH Level
Based on a scale from 0 to 14, where 7 is considered neutral, meaning a liquid is neither an acid nor a base. Water is an example. The further away from 7 (up or down), the more irritating the substance can be to skin. The natural pH of healthy skin is around 5.5, which means it is slightly acidic. Good soap ranges from 8 to 9, so it is slightly basic. The more basic a soap is, the harsher it can be to the skin.

Pour Temperature
The temperature at which pouring soap into a mold produces optimal results. Testing should be performed to determine the optimal temperature for your application.

Saponification
The chemical reaction that takes place when fat (vegetable oils or animal fats) and sodium hydroxide (alkali) are mixed together. The result produces glycerine and salts of fatty acids.

Soap
A mixture of the alkali-salts of fatty acids. The alkali-salts of fatty acids act as surfactants and allow water to wash away oily dirt. In real life, a substance derived from vegetable oils and/or animal fats that have been "saponified" with lye. The resulting alkali-salt of fatty acids has cleansing properties, and no additional ingredients (like sulfates) have been added to improve the cleansing properties.

Sulfates
A powerful form of detergent made up of sulfur attached to a fatty acid, the most common being Sodium Lauryl Sulfate (SLS). They can attract both water and oil, which help lift dirt and wash it away more easily. People with sensitive skin can find this ingredient irritating, but there are milder options available.

Surface Tension
The elastic tendency of a fluid surface. For example, water droplets have a high surface tension so they hold together tightly. In soap making, products like isopropyl alcohol and various surfactants are used to reduce surface tension to produce different results.

Surfactant
A substance that works to reduce the surface tension between oils and water. Their structures contain a water-loving part and an oil-loving part. It can function as a detergent, wetting agent, emulsifier, foaming agent, or some combination of these.

Sweating
A common occurrence in melt and pour soaps, sweating happens when the soap is not wrapped tightly and the glycerin in the soap is pulling moisture from the air, forming beads of water on the surface.

Translucent
Light can pass through, but the object will appear cloudy or hazy. For example, frosted glass.

Transparent
Light can pass through and the object can visually be looked through easily. For example, a window.

Vanilla Stabilizer
Helps prevent or minimize discoloration in soap or bath and body products caused by a fragrance ingredient called vanillin, commonly known as vanilla.

Wetting Agent
Used to break the surface tension of a liquid so that it spreads easily. This is useful in soap so that water droplets take up more space on your skin to help soap do its job to pick up dirt and oil.