Roasting Guide

This is a quick reference guide for steps to follow when preparing to roasting coffee for the first time, or simply to use as a reminder of things to do, and pay attention to.  This outline will not tell you answers on how to properly build a roast curve, when or why to apply airflow, or reduce heat at a certain time. On the other hand, it should inspire you to find answers to questions you may not have had prior to reading through this guide.


  • Are you qualified to roast on your own? (if not, stop here, register for a roasting class)
  • Fire suppression system nearby? Does it work? (water sprayer, fire extinguisher,etc. (See Section 6 for Emergency Procedures)
  • Unqualified people nearby, children, pets, or other unusual distractions?
  • Are you mentally focused, have green coffee and equipment ready to go?
    • Scale
    • Scoop
    • Green coffee
    • Notebook (computer or paper/pen)
    • Timer (computer or other)
    • Scheduled roasts, how many batches, which order?
  • First inspect chaff collector, clean if necessary, secure when complete
  • Inspect gas line (if closed, open)
  • Inspect electric power (check to ensure it is plugged in)
  • Inspect Airflow position: Check ventilation, HVAC system, and adjust exhaust/airflow to recommended positions.
  • For the Diedrich IR-12, there are (3) airflow positions 
    • Drum: Forward Position pulls air through the Drum, while also slows the cooling of coffee in the cooling tray if present.
    • Cooling Bin: Upward/Back position pulls air through the Cooling Tray, helping quickly cool the coffee resting in the cooling tray. at the same time, this position slows the speed of air through the drum, causing the drum to increase in heat retention. 
  • Ignite electric starter for gas by flipping the toggle switch on the board (need time for gas to fill lines)
  • Set gas dial to 3-7, with airflow through the cooling tray position.
  • Heat to recommended charge temperatures (350-400F) which depends similar to ventilation variables, along with green coffee conditions and intended roast profile.



Ensure ample time is given to season the drum with proper heat absorption. This may take 15 minutes or longer depending on the environmental conditions. While you are waiting, ensure your roasting plan and profiles are ready to go, and begin to weigh out your first batch of green coffee into a container and stage the coffee nearby to be ready to load into the hopper.


  • Set Cropster Profiles or manual logging system preparing the following for recording:
    • Time (30sec interval preferred)
    • Charge Temp
    • Air Flow setting
    • Gas setting



  • Green coffee
    • Density (bulk/actual)
    • Moisture (water activity, content)
    • Bean size (screen size 14-20)
    • Processing method (natural, pulped, washed)
  • Temperature:
    • source of energy: natural gas, propane, electric
    • Delivery of heat: fluid bed, radiant ceramic tile, indirect flame, direct flame, recirculation
    • % of type of heat transfer: convection, conduction, radiant/infrared
  • Human operator condition
    • Focus, preparation, scientific, craft, level of interest, bad day?
  • Environmental condition
    • Relative humidity, does the style of the roaster allow this to impact roast curve
    • Room temperature (winter/summer
  • Time
    • Amount of time applied to each variable to create profile
  • Mechanical conditions
    • Type of drum material
    • Design for heat transfer
      • Indirect Heat, Radiant Heat, Direct Flame, Fluid-Bed, Recirculated Heat,
    • Damper for airflow, drum speed regulation
    • Batch Capacity %
    • Charge Temperature needs for specific type of machine
  • Airflow
    • Type of airflow Recirculating, fluid bed, convection
    • Speed
    • volume
    • temperature
  • Agitation
    • drum speed, paddle, fluid bed



  • Once the roast profile is complete, open door to discharge roasted coffee into the cooling tray.
  • Industry standard suggests cooling coffee to room temperature within 4 minutes.
  • After final roast is complete, set gas to (0) position
  • Wait for temperature to reduce to 200F



If fire in the roasting drum…

  • Leave the roast coffee in the roasting drum, do not empty the drum!
  • Avoid the entry of air.
  • Close the gas tap.
  • Wait for the machine too cool down.

If fire on the cooling sieve…

  • Close the gas tap.
  • Switch off the main switch for the electrical supply.
  • Extinguish the roast coffee with water.

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