Coffee Data Science
How accurate are Acaia and Syncfo Scales for Coffee?
More tests for equipment
The Syncfo 4in1 has a scale to the 0.1g, but how accurate is it? I’m using this device for coffee measurements, and I need to know how well it can perform. I typically use a Acaia Pyxis scale (0.01g resolution, 0.03g accuracy), and I recently bought a Bonsoivin scientific scale that resolves to 0.001g.
For these tests, I saw the Pyxis on top of each of these scales, and using a container, added coffee beans slowly. I measured the weight and then calculated the weight changes between steps.
Note: Calibration testing should be done using calibration weights, but I wasn’t going to buy a calibration weight set. I have a calibration weight for each device, and they are calibrated. I was really interested in how they compared to one another.
I collected 30 samples for each sets of data.
Syncfo 4in1 vs Pyxis
I started comparing the Syncfo to the Pyxis. The readings were mostly the same, but there was a little offset at the beginning which later corrected.
The differences between samples were great, except for two points where the scales had an offset fixed in the next sample.
From a statistical standpoint, there is a small difference in absolute difference that is statistical, but the difference between samples is not statistically significant.
Pyxis vs High Precision
I then wanted to make sure my beloved Pyxis was accurate. I looked at the absolute weight, and the line went very well.
The difference between samples showed a similar trend.
There was a small difference (-0.0050) that was statistically significant, but that is lower than the smallest resolvable weight for the Pyxis. The difference between samples is minimal and not statistically significant.
Both of these of these tests showed me that the two scales work well, and I can trust the numbers from any of them. I’m actually planning on using the higher precision scale as much as possible.
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Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
