Ever Felt Lost in the World of Lye, Saponification, or Trace?

Master the language of soap crafting! This A-Z glossary simplifies 50+ essential soap making terms — from trace and lye safety to superfatting and gel phase — with clear definitions and pro tips. Whether you’re troubleshooting false trace or experimenting with cold process (CP), this guide helps beginners and experts alike communicate like seasoned soap makers.

Why Terminology Matters

Whether you’re a beginner learning about trace or a seasoned maker troubleshooting seizing, using the correct jargon is essential to:

• Communicate clearly with other crafters.
• Understand recipes and tutorials accurately.
• Avoid costly mistakes (like false trace or lye-heavy soap).

*“Think of this glossary as your soap-making translator. Now, when a recipe says ‘superfat by 5%’ or ‘watch for medium trace,’ you’ll know exactly what to do!”*

How to Use This Guide

1. Browse the alphabetical index below to jump to any term.
2. Bookmark this page for quick reference mid-project.
3. Share with fellow crafters to spread the knowledge!

Alphabetical Index

A
Additive | Aromatic Oils (FO)

B
Base Oils

C
Caustic | Cold Process (CP) | Curing

D
Discount

E
Essential Oils (EO)

F
False Trace | Fixed Oils | Flash Point | Fragrance Oils (FO)

G
Gel Phase

H
Hot Process (HP)

L
Lye | Lye Heavy Soap

S
Saponification Value (SAP) | Seizing | Soap Batter | Superfat

T
Trace

V
Volcano Effect

Soap Making Terms Defined

Each term includes a definition, related concepts, and practical tips for flawless soap crafting.

Additive

Optional ingredient (e.g., fragrance, color, exfoliants) added at light trace to modify soap properties.
See also: Trace, Cold Process.
Tip: Avoid additives that accelerate trace (e.g., certain clays).

Aromatic Oils (Fragrance Oils, FO)

Synthetic scented oils blended with carrier oils (e.g., mineral oil).
See also: Essential Oils, Flash Point.
Tip: Check flash points to prevent evaporation during mixing.

Base Oils (Fixed Oils)

Non-volatile oils (e.g., olive, coconut) used as soap’s primary fats.
See also: Saponification Value.

Caustic

Substance (like lye) that burns organic tissue via chemical reaction.
See also: Lye, Safety Precautions.
⚠️ Warning: Always wear gloves/glasses when handling lye.

Cold Process (CP)

Method where lye + oils emulsify without external heat; requires 4–6 weeks curing.
See also: Trace, Gel Phase, Curing.
Tip: Insulate molds to encourage gel phase.

Curing

4–6 week drying period post-molding to complete saponification and harden bars.
See also: Cold Process, Water Discount.
Tip: Longer curing = harder, longer-lasting soap.

Discount

Reducing lye or water in a recipe (e.g., 5% lye discount = superfatting).
See also: Superfatting, Seize.
⚠️ Warning: Water discounts speed trace but risk seizing.

Essential Oils (EO)

Natural plant-extracted scents added to soap.
See also: Fragrance Oils, Flash Point.
Tip: Some EOs accelerate trace (e.g., cinnamon).

False Trace

Batter thickens due to cooling fats (e.g., tallow), not saponification.
See also: Trace, Hot Process.
⚠️ Warning: Keep batter warm to avoid false trace.

Fixed Oils

Non-volatile oils that withstand high temperatures without evaporating (e.g., olive, coconut, palm).
See also: Base Oils, Saponification Value.

Flash Point

Temperature at which oils vaporize and lose fragrance.
See also: Fragrance Oils, Hot Process.
*Tip: Add EOs/FOs below flash point (~120–200°F).*

Fragrance Oils (FO)

Synthetic scented oils blended with carrier oils (e.g., mineral oil). Also called Aromatic Oils.
See also: Essential Oils, Flash Point.
Tip: FOs often have higher flash points than EOs.

Gel Phase

Stage where soap becomes translucent and gel-like during saponification (optional in CP).
See also: Cold Process, Hot Process.
Tip: Gel phase intensifies colors but may overheat delicate additives.

Hot Process (HP)

Soap-making method using external heat to accelerate saponification; no curing needed.
See also: Cold Process, Gel Phase.
⚠️ Warning: HP soap has a rustic texture and may not work with low-flash-point EOs.

Lye (Sodium Hydroxide)

Caustic alkali that saponifies oils into soap. Essential for CP/HP but requires strict safety measures.
See also: Saponification, Safety Precautions.
⚠️ Warning: Always add lye to water (never reverse!).

Lye Heavy Soap

Soap with unreacted lye, causing skin irritation. Usually a recipe error.
See also: Saponification Value, Discount.
Tip: Use a lye calculator to avoid this.

Saponification Value (SAP)

Amount of lye needed to saponify 1g of oil. Varies by oil type.
See also: Lye Discount, Superfatting.
Tip: Oils high in stearic acid (e.g., tallow) require less lye.

Seizing

Sudden, irreversible thickening of soap batter, making it un-pourable.
See also: Trace, Water Discount.
⚠️ Common causes: Low water, high-stearic oils, or certain FOs/EOs.

Soap Batter

Emulsified mixture of lye, water, and oils before molding.
See also: Trace, Gel Phase.
Tip: Stir slowly to minimize air bubbles.

Superfat

An excess of un-saponified oils in soap for emolient quality (typically 5–8%).
See also: Lye Discount, SAP Value.
Tip: High superfat (>10%) can make soap greasy.

Trace

Pudding-like consistency indicating saponification is underway.
See also: False Trace, Seize.
Tip: Light trace = ideal for swirls; thick trace = rustic designs.

Volcano Effect

Dangerous eruption when water is poured into lye (instead of lye into water).
See also: Lye, Safety.
⚠️ Critical: Always add lye to water in a well-ventilated area.