tags: [] - coffee/roasting aliases: - Coffee roast profile - Roasting profile - Roast curve

Roast Profile¶

Tags: #coffee/roasting Aliases: Coffee roast profile, Roasting profile, Roast curve Related: Roasting Methods MOC | First & Second Crack | Maillard Reaction | Roast Development Ratio | Heat Transfer in Coffee Roasting Status: ✅ Complete

Overview¶

A roast profile is the complete record of temperature and time during a coffee roasting batch, describing how heat is applied to green coffee from charge (loading) to drop (end of roast). Roast profiles are tracked using the bean temperature curve (BT), the rate of rise (RoR — degrees per minute), and environmental temperature (ET) from a drum roaster or fluid-bed roaster. By controlling the shape of the profile, roasters manipulate the chemical reactions occurring in the bean — Maillard browning, caramelisation, organic acid breakdown, and volatile compound formation — to achieve a target flavour outcome.

Key Phases of a Roast Profile¶

Phase	Temperature range (BT)	Duration (typical)	What occurs
Charge and drying	Ambient → ~150°C	3–6 min	Moisture driven off; bean turns yellow; endothermic
Maillard / browning	~150°C → ~185°C	4–6 min	Amino acid + reducing sugar reactions; brown colour develops; complex aromatic compounds form
First crack	~185–200°C	1–2 min	Exothermic; audible cracking; CO₂ release; bean expands
Roast development	After first crack	1–5 min	Flavour development; Maillard continues; light roast drops here
Second crack	~220–230°C	—	Dark roast territory; oils released; carbons form

Rate of Rise (RoR)¶

Rate of rise is the rate at which bean temperature increases, measured in degrees per minute or degrees per 30 seconds. RoR management is central to profile control:

Declining RoR: A smooth, continuously declining RoR from charge to drop is widely considered the target profile shape — indicates controlled, even heat transfer without stalling or flicking
RoR crash / stall: Sudden drop in RoR; associated with underdevelopment and grassy flavours
RoR flick: Upturn in RoR near end of roast; associated with scorching, roasty, or ashy flavours
Flat / prolonged RoR: Extended time in one temperature range; can bake flavours into the coffee

Roast Development Time (RDT)¶

Roast Development Time is the time from first crack to the drop point. The Roast Development Ratio (RDR) expresses RDT as a percentage of total roast time:

RDR = RDT ÷ Total Roast Time × 100

Common targets: 20–25% RDR is a typical specialty coffee reference point, though this varies by roaster style, coffee, and equipment.

Profile Design Variables¶

Variable	Effect
Charge temperature	Affects early bean temperature trajectory
Heat input (gas, air)	Controls RoR; more heat = faster rise
Drum speed	Affects heat transfer consistency and airflow
Airflow	Controls convective heat; also vents moisture and gases
Batch size	Affects thermal mass and profile shape
Drop temperature	Determines roast level (light/medium/dark)

Key Facts¶

A roast profile records bean temperature and rate of rise from charge to drop; defines the thermal journey of green coffee through roasting
Key phases: drying → Maillard → first crack → development → (second crack for dark roast)
Declining rate of rise is the target profile shape; a stalling or flicking RoR indicates problems
Roast Development Ratio (RDR) measures post-first crack time as a percentage of total roast time; specialty coffee typically 20–25%
Profiling software (Cropster, Artisan) records and compares profiles, enabling repeatable roasting

References¶

Changelog¶

Date	Change
2026-04-28	Note created

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