pH – Scale used to measure the acidity or alkalinity of a substance. The pH of a
substance can range from 0, for very acidic materials, to 14 for alkaline (or basic)
substances, with 7 being neutral.
pH Tongue Test – Quick test to determine pH level of soap.
Phenolphthalein – A reagent that can be used to detect high levels of pH. This
chemical is clear, and will turn pink if it comes into contact with a substance that has
a pH over 7; the darker the pink, the higher the pH.
Potassium Hydroxide – KOH; also called potash, caustic potash, potash lye, and
potassium hydrate. Commonly used to make liquid soaps.
Rebatching (Rebatch Process) – Method of soap-making in which previously made
soap is melted and remixed to form new bars.
Saponification – Refers to the chemical process in which lye and oils are combined,
and neutralize one another, forming soap.
Saponification Value (SAP value) – The number of milligrams of lye required to
completely saponify one gram of a specific fat.
Saturated Fats – Fats that are solid at room temperature. These fats make a very hard
bar of soap, and must be melted before use.
Seize – The phase of cold-process or hot-process soap-making when saponification is
complete, and the batter begins to solidify, and becomes too thick to mix or pour into
a mold. The soap must be molded before this phase.
Soap – Anionic surfactant. Technically a salt, produced via the chemical reaction
between lye and fat.
Sodium Hydroxide – NaOH; also called lye, ascarite, caustic soda, soda ash, soda lye,
sodium hydrate, and white caustic. Commonly used to make solid soaps.
Sodium Tallowate – Rendered beef tallow.
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