Coffee Data Science
Moisture Added for Green Coffee for a Week
Wait and see
Adding moisture to green coffee improves flavor in coffee roasting, and I was curious how long can the coffee with more moisture sit before it affects flavor. I made three roasts, starting with adding 6% moisture to all three:
- Waiting 24 hours
- Waiting 72 hours
- Waiting 168 hours (1 week)
I froze each roast after the wait time so I could roast all of them at the same time on the Roest.
Post-Roast Metrics
All three roasts had similar roast metrics.
There was a slight deviation of color for 72 hours, so we have to be careful.
Metrics of Performance
I used two sets of metrics for evaluating the differences between techniques: Final Score and Coffee Extraction.
Final score is the average of a scorecard of 7 metrics (Sharp, Rich, Syrup, Sweet, Sour, Bitter, and Aftertaste). These scores were subjective, of course, but they were calibrated to my tastes and helped me improve my shots. There is some variation in the scores. My aim was to be consistent for each metric, but some times the granularity was difficult.
Total Dissolved Solids (TDS) is measured using a refractometer, and this number combined with the output weight of the shot and the input weight of the coffee is used to determine the percentage of coffee extracted into the cup, called Extraction Yield (EY).
Data
I pulled 4 shot pairs, and I found the 72 H and 168 H performed close to the baseline (24 H) or worse.
EY was not affected.
This data suggests a longer rest time post-moisturization is not ideal for taste. I forgot to measure water activity because that might have been an interesting indicator.
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Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
