tags: [] - coffee/roasting - coffee/equipment - coffee/education aliases: - Roasting Equipment module - Roast profiles course module

Module 4 — Roasting Equipment & Profiles¶

Tags: #coffee/roasting #coffee/equipment #coffee/education Aliases: Roasting Equipment module, Roast profiles course module Related: Roasting MOC | Roast Profile | Air roaster | Sample roasters | Heat Transfer in Coffee Roasting Status: ✅ Complete

Overview¶

Module 4 covers the equipment used for coffee roasting — from home air roasters through sample roasters to commercial drum roasters — and the principles of roast profile development: how roasters design, execute, and adjust temperature curves to achieve consistent and repeatable flavour outcomes. Understanding roasting equipment and profile management is essential for anyone operating a roastery or pursuing SCA Roasting Skills qualifications.

Module Content¶

4.1 — Roaster Types and Their Characteristics¶

Different roaster types balance heat transfer modes differently, producing distinct roast characters:

Roaster type	Primary heat mode	Typical use	Key article
Drum roaster	Conduction + convection	Home to commercial; most common type	Heat Transfer in Coffee Roasting
Fluid-bed (air) roaster	Convection dominant	Home; commercial (some); fast roast	Fluid-bed (air) roasters
Sample roaster	Conduction; small batch	Green coffee evaluation; QC	Sample roasters
Hybrid roaster	Adjustable conduction/convection ratio	Specialty commercial; profile flexibility	Roasting MOC

Home air roasters: Air roaster — accessible entry to home roasting; limited batch size; fast roast; good transparency of roast progress

Sample roasters: Sample roasters — used by green coffee buyers and roasters to evaluate small batches; 50–150 g capacity; rapid evaluation of lots

4.2 — Roast Profile Components¶

A roast profile is the complete temperature-time curve of a roast, typically recorded by roasting software:

Phase	Description
Charge	Beans loaded at charge temperature; drum pre-heated
Drying phase	Beans absorb heat; moisture evaporates; colour change begins
Maillard phase	Temperature rises; Maillard reactions begin; yellowing to light brown
First crack	Audible crack; light roast achieved; development phase begins
Development	Post-crack time where DTR controls final flavour
Drop	Beans released from drum; rapid cooling essential

See Roast Profile for the complete treatment.

4.3 — Rate of Rise (RoR) Management¶

The Rate of Rise (RoR) — bean temperature increase in °C per minute — is the primary active management variable during a roast:

Declining RoR profile: The standard approach; RoR steadily falls through the roast; avoids "RoR crashes" or "RoR spikes" that indicate inconsistent heat application
Stalling RoR: A sudden drop in RoR often indicates a problem (insufficient heat input); may produce baked flavours
Flick (RoR increase post-crack): A sharp RoR increase after first crack; generally undesirable; associated with under-development

Roasters monitor RoR through roasting software (Cropster, Artisan, RoasTime) connected to temperature probes in the drum.

4.4 — Development Time Ratio (DTR)¶

DTR is the percentage of total roast time spent between first crack and the drop:

Calculation: Development time ÷ total roast time × 100
Typical range: 20–25% for most specialty applications
Effect: Higher DTR increases sweetness and reduces acidity; lower DTR preserves acidity and origin character but risks under-development

See Roast Development Ratio.

4.5 — Consistency and Repeatability¶

A repeatable roast requires: - Consistent bean temperature at charge - Consistent batch size (within ±5% of rated capacity recommended) - Consistent gas pressure and airflow settings - Temperature logging and profile comparison across batches - Regular cleaning of drum and chaff collector

Roasting software (Cropster, Artisan, Aillio RoasTime) enables batch-to-batch comparison and profile replay.

Key Facts¶

Drum roasters are the most common type across home-to-commercial; primarily conduction and convection heat transfer
Fluid-bed (air) roasters are convection-dominant; faster roast; lighter, more transparent cup character
Sample roasters (50–150 g) are essential for green coffee quality evaluation in a roastery
Declining RoR profile is the standard specialty roasting target; stalls and crashes indicate heat transfer problems
DTR (Development Time Ratio) of 20–25% is a common specialty target; controls the balance between sweetness and acidity

References¶

Changelog¶

Date	Change
2026-04-29	Note created

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