Coffee Data Science
Coffee Metrics Through Roast Development
Simple experiments to start
As part of my dive into more data for coffee roasting, I wanted some initial data to give me an idea how variables change during the roast. Specifically, I am using a Syncfo 4in1 to measure density, moisture, and color. I used a Roest to repeat a coffee roast a few times with some test coffee, and I looked how development affected the different metrics.
I looked at the First Crack (FC), and then 45s, 75s, and 105s after the FC in 100g batches to start, and then I looked at some 50g batches.
100g Batches
Previously, I have looked a roasted weight loss by dividing the roasted weight by the green weight. This is a similar and expected trend.
Density seems to bottom out, and I suspect this would change at the second crack, but I would rarely take a roast darker than FC 105s.
Moisture continues also bottoms out, and I don’t know if this is a limit to the measurement or if there is actually that much moisture there. I have other experiments to try to understand the moisture reader and how moisture presents in beans.
Color continues to decline, which is expected, but it does not seem quite linear.
We can also compare roast color to weight loss. For this simple experiment, there looks to be a clear connection to color.
Luckily, we have a lot more data from other roasts, which show a general trend but not quite a direct correlation.
50g Batches
I also did smaller batches of 50g, but it was not enough for the moisture or density metric. So I calculated density using a 80 mL tube.
During these tests, I had a few more data points to show the loss in weight.
Density certainly flattened out, but there was still a slight slope.
Color kept going down, and the FC+180s was the start of the second crack.
In plotting color and weight loss again, there is a seemingly linear trend.
These experiments have helped me level set on expectations for roasting experiments. I am curious how different modifications to the roasting process will affects these variables.
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Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
