Coffee Data Science
Coffee Roasting: RPM x Charge
Mixing variables
Previously, I looked at charge, and now I want to conflate the charge with drum RPM to see their combined impact on the roast.
Roasting
I used Scott Rao’s roast profile on the Roest that uses bean temperature as turning points for inlet temperature. This is my baseline profile.
Roast Data
Slower drum speed resulted in a longer roast as did a lower charge. There was some cross-over with 65 RPM at 50 C charge and 20 RPM at 300 C.
Rate of Rise (RoR) was pretty similar aside from the 50 C charge.
The number of cracks was similar across the two drum speeds with somewhat similar patterns.
Post-Roast Data
These roasts were very close in weight loss.
The same was true for bean moisture.
Bean color only had a slight downward trend at 20 RPM.
Similar for the other metrics, bean density is similar.
Drum RPM and Charge Temperature don’t seem to have a particular interaction from this small data collection. However, this data is just a smidge of data, so there is probably more nuance to these variables. My aim is to see if there is a major impact that would be clear to see from a small experiment before moving on to a larger experiment.
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Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
