Roast Genie

The Roast Genie is a controller and data management system I am building to improve the performance of my Gene Cafe coffee roaster, enable more detailed data logging, and in general to provide a better way to study and improve my roasts.

The system consists of five parts:

1) A modified Gene Cafe coffee roaster.

2) An Arduino-based micro-controller that provides real-time control of the roaster and a user interface.

3) A Raspberry Pi to manage the coffee data including pictures of the roasted beans and plots of the roasting data.

4) Scripting services and network storage.

5) A website to store and share roasting data and tasting notes.

The idea behind the Roast Genie is to make it very easy to collect data while roasting, present and share that data in a meaningful way, and add roasting and tasting notes in a centralized place at a later time — all with the purpose of improving roasting techniques.



  • Measures and records the temperature of the air stream entering the roast drum.
  • Measures and records the temperature of the air stream leaving the roast drum.
  • Provides smooth, continuous power control to the heater using a Triac and PID.
  • Records roast data including, coffee type, green and roasted weight, time and date of roast, as well as all of the roasting temperature data.
  • Permits control of drum speed and fan speed during the roasting process.
  • Provides automatic roast profiles with on-the-fly adjustment.
  • Prints roast data to a receipt that can be kept with the batch of roasted beans to identify the batch and important roast parameters.
  • Takes a picture of the roasted beans and automatically prepares a plot of the roast profile.
  • Connects through wifi to a network file server for data storage and subsequent post-process of data.
  • Automatically creates blog postings with plots of roast profiles where roasting and tasting notes can be added at a later time.

Second Generation Roast Genie

Overview Diagram


Overview Photo

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