Coffee roasting: changes during the roasting process


What you see above is a log of visual changes during the coffee roasting process. The picture was taken with my phone and then cropped and edited on my desktop computer. Colors weren’t adjusted but brightness, exposure, and dimensions were altered.

From left to right are eight coffee samples lifted out of our coffee roaster. Elapsed time is shown at the top of the picture while recorded bean temperature is shown at the bottom of the picture. Samples were taken from one roast batch.

When we first receive coffee, the beans look most like the sample on the far left, green coffee. Depending on your tastes, when you receive coffee, the beans look most like one of the four samples toward the right.

While a change in color is obvious, take a look at the change in bean size during the roast process. As the bean is roasted, it is drying from a moisture content of 1