Coffee Data Science
Re-roasting Stale Coffee?
Could a second roast bring stale coffee back to life?
I was curious to find out if re-roasting coffee beans could bring new life from them, so I got a few coffees that were 3, 4, and 7 months old. I re-roasted them just to the first crack on the Roest, and then I tasted them.
Spoiler alert: they were still stale and gross.
After a second roast, the beans lost more weight from their starting point.
In terms of moisture and water activity, the water activity was already low which is probably telling of the roasts being stale to begin with. Re-roasting didn’t help.
In terms of coffee color, their agtron values went down so they got darker. The re-roast also became less dense. However, the oldest roast from 5/28/2024 gained. I suspect there was an error in measurement.
From smell alone, these coffees were going to be terrible. I brewed two espresso shots, and I didn’t even record the grades because I didn’t try but a tiny taste. I also spit that small amount of coffee out. I am curious if other processing could bring a stale coffee back to life. I also doubt it would work well, but I wanted to try for the sake of a simple experiment.
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Further readings of mine:
My Second Book: Advanced Espresso
My First Book: Engineering Better Espresso
