Ground vs Whole Bean Degassing

In this experiment, I roasted Costa Rica coffee to Full city. I dropped the roast at 450^oF. While I normally do not roast so dark, I knew from documentation this would result in more CO2 to be released.

I placed 100 grams of ground coffee in the the left flask, while 100 grams of whole beans were placed in the right flask. I loaded the ground coffee into the flask as quickly as possible, but the degassing speed surprised me. In one hour of capping the flask, 120 ml of CO2 was already released. This is much faster than whole bean degassing. In the previous whole bean experiment with a medium roast and twice the coffee it took 24 hours to release 120 ml.

Another change from the previous setup was to add eye droppers to the end of the tubes. This made it easier to see the bubbles form. Play the video to see how fast the ground coffee released CO₂.

Hours ml CO2 0 0 0.08 28 0.13 40 0.23 58 0.27 62 0.28 65 0.35 72 0.38 78 0.45 84 0.52 90 0.60 96 0.67 102 0.80 110 0.90 116 0.95 118 1.00 120 1.07 126 1.15 130 1.37 138 1.48 144 1.88 158 2.00 160 2.30 166 3.13 186 3.53 194 5.00 212 6.83 228 8.78 238 19.00 256 31.00 268

Roast profile from the Artisan tracking screen.

This shot image was captured with a Celestron digital microscope. The scale on the right is 1/16″. The beans were ground with a Macap MC4.