Indicator Information

• EC showing real-time concentration changes. Like roasting profile software, extraction profile software is also very useful.
• We measure real-time concentration because we believed that to analyze the extraction process, we need to understand when and how coffee compounds are extracted.
• EC (electrical conductivity meter) is used because flowing coffee concentration cannot be measured with a TDS refractometer. While EC and TDS are different by definition, It is sufficient for observing the shape of concentration changes during extraction.
• EC shows the actual extraction flow in detail. This is the information that baristas try to observe with bottomless portafilters.

Evaluate brew quality

• Evaluating Stability (channeling, etc.)

  

  Stable, slightly unstable, or severely unstable.

  • An unstable brew, even if it tasted good, would be hard to reproduce consistently.

• Evaluating Consistency

  

  Consistent, inconsistent.

  • Achieving perfect continuous brew consistency can be challenging, but you will be able to set QC standards more clearly by seeing what range of deviations will achieve satisfactory flavor consistency.

Types of log shape

• Initial EC
  • We estimate that the initial EC shows how evenly the brew water passed through the puck initially. Care must be taken in interpretation as EC may read low if there is too little flowing coffee to properly contact the EC probe.
• Early Delay
  • Generally, when this section is too long, extraction consistency tends to be poor.
• Mid-decline and Late Angle Changes
  • Many users evaluate that a flat line is better than a rebound, and a gradual decline is better than that.
• Types 1 and 2
  • These were generally observed in high-flow extractions.
  • Compared to other types, these are relatively easier to extract consistently, and baristas' extraction procedures appeared shorter.
• Types 6 and 7
  • These were generally observed in low-flow extractions.
  • Many users prefer an 'S-shaped' EC line with smooth gradient changes or a 'gentle linear' pattern with minimal gradient changes.
  • Compared to other types, these are relatively harder to extract consistently, and baristas appeared to perform more puck prep. actions.