Hydrophilic – Attracted to water. Water, and substances that can be dissolved in it,
are hydrophilic.
Hydrophobic – Repelled by water. Oil, and substances that can be dissolved in it, are
hydrophobic.
Hygroscopic – An adjective used to describe a material that has a tendency to absorb
moisture from the air.
Immiscible – A substance into which a material cannot dissolve.
Lye – Sodium hydroxide (NaOH) or potassium hydroxide (KOH). Sodium hydroxide
makes hard soap; potassium hydroxide makes softer soap, and is typically used to
make liquid soap or shaving cream.
Lye discount – The process of withholding a percentage of the lye needed to saponify
the fats from the soap mixture. For example, a 5% lye discount means that only 95%
of the amount of lye necessary to neutralize all of the oils is actually used. Also
called superfat discounting.
Material Safety Data Sheet (MSDS) – Contains important handling and safety
information for the given material. Always review the MSDS before working with a
new material.
Melt-and-Pour Process – A method of soap-making in which premade soap base is
used to make soap. The soap-maker melts the soap base, adds his or her own
additives, and remolds the bars. Easy and safe, but little control over ingredient
quality, and can be expensive.
Micelles – Clusters of molecules that surround and suspend another. Soap molecules
form micelles to surround and suspend grease particles.
Oleochemicals – Chemicals derived from fats and oils.
Petrochemicals – Chemicals derived from fossil fuels.
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