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Research Field Transformation of Coffee

Roasting, grinding, degassing, packaging, and coffee freshness

Lead: Dr. Samo Smrke

The research field "Transformation of Coffee" is responsible for projects involving coffee processes where green coffee beans are transformed into ground coffee ready for extraction. Studying these processes involves research about roasting, grinding, packaging and storage, aroma stability, coffee degassing, and capsule production.

Reference Projects

Coffee Roasting Intelligence

Project Name: Coffee Roasting Intelligence

Project Partner(s): Mikafi GmbH

Funding Partner: Innosuisse (35601.1)

Project Status: completed

In the Coffee Roasting Intelligence project we developed models for coffee roasting intelligence, so that coffee roast profiles can be chosen based on desired coffee flavour attributes. This was done by combining understanding of coffee chemical composition and sensory analysis of coffee. At the end of the project Mikafi launched their coffee roaster at HOST 2023.

Aroma Capture

Project Name: Aroma Recovery from Coffee Roasting

Project Partner(s): Jacobs Douwe Egberts (JDE)

Funding Partner: Third Party

Project Status: completed

We developed a novel sampling system for sampling aroma compounds above ground coffee or whole beans in a highly controlled way and analyze by PTR-ToF-MS. This enabled us to implement the PTR-MS capabilities of direct quantification of volatile organic compounds on the headspace and measure dynamics or aroma release from coffee. Deep understanding of aroma release and carbon dioxide degassing dynamics was obtained, as a function of grind size, roast level, roast time, green coffee type and moisture content. A publication describing the methodology and studies of fundamentals of aroma release from ground coffee is in preparation.

Lab equipment and measurements

Proton-Transfer Mass Spectrometry (PTR-MS)

  • Core technology of CEC for monitoring and quantification of volatile organic compound in dynamic processes (up to 1 s time resolution)
  • PTR-MS is coupled to an autosampler for rapid sample analysis by PTR-MS
  • We have extensive experience building sampling setups for PTR-MS sampling from a wide range of samples and experiments, for example:
    • Sampling high temperature, highly contaminated gas (e.g. coffee roaster exhaust)
    • Sampling VOCs from the flow of coffee from a coffee machine
    • Sampling from high pressure, up to 50 bar
    • Nose- and mouth-space analysis
    • Release or aroma after soluble coffee reconstitution
    • Customs setups for fundamental studies, such as VOC release dynamics and partitioning measurements (Henry Law constant determination)

The Coffee Excellence Center has capacity for precision laboratory coffee roasting using state of the art and traditional coffee sample roasters:

  • 2x Roest S100 sample roaster
  • Probat BRZ sample roaster
  • Probat SE sample roaster
  • 2x Ikawa 50g sample roaster

We have two shop roasters around the 1kg batch size:

  • Probat Probatino 1kg
  • Stronghold S7 (800 g)

For analysis of roasted coffee we have the standard equipment used in coffee roasting QC:

  • Probat Collorette 3B and 4
  • LAB colour meter
  • Coffee moisture and density meter based on capacitive measurements (Sinar)
  • Coffee moisture measurements by drying
  • Water activity meter

Reports, articles and media contributions