January 05, 2005
pop-roasted coffee experiment
For the benefit of caffeine-geeks everywhere, these are the chronicles of a Saturday night engaged in the latest underground craze: roasting coffee in a popcorn machine.
Quality coffee will result --which quality, exactly, we cannot predict -- and we will doubtlessly drink it.
In the beginning: like popcorn, raw beans are smaller than cooked. Wow!
-200 g. green coffee beans (Colombian fair-trade organic shade yadda...)
-1 "corn popper" machine, 1/2 c. capacity, non-mesh interior (IMPORTANT: mesh-lined machines snag bean chaff which then catch fire!)
-1 large metal sieve
-1 9" square sheet of aluminum foil
-1 mortar and pestle
-1 stainless steel pot, 1.5 l. capacity
-1 hand coffee filter
-3 mugs and spoons
-cream and sugar
1. We divided our bounty of beans into 4 approximately equal mounds in order to maximally explore the subtleties of pop-roasting.
2. We pointed our "corn popper" towards the sink, plugged it in, and deposited the first batch of beans. They whirled around entertainingly.
3. Internet Wisdom claims that pop-roasting beans should emit "fragrant smoke" and a distinct snapping sound, known as "first crack", after 3 minutes. In fact, our machine only persuaded smoke and browning after 5 minutes. In the meantime, a lot of messy chaff poured directly into the sink, which made us feel clever.
4. We identified "first crack" at approximately 8.5 minutes, by what was less a distinct snapping and more of a light puttering. Forewarned of exponential heating past first crack, we dumped the searing hot, very light-medium roasted beans into our sieve and shook them around to finish cooking and to cool.
5. The first batch of beans darkened only slightly in the sieve, stabilizing at a light medium roast.
The first batch
6. Unmeasured minutes after the first batch was deposited onto a plate, we poured in the second batch. We followed the same process, but this time the preheated "corn popper" achieved first crack after only 6.5 minutes. As we desired a darker roast, we let the machine run for an additional 3 minutes, at which point the hood of the "corn popper" began to wilt and form tiny bubbles, and had to be removed.
Note the warped vents of the hood. We were better off without it.
7. We sieved the second batch at 9.5 minutes. It was only darker than the first if we squinted right.
8. The hood now replaced with a 9" square of aluminum foil, we aspired to pop-roast a third and final batch and really "give'er". Unfortunately, the "corn popper" was fatigued and first crack did not occur until... well, what with "givin'er" and all we didn't specifically notice -- it took longer than 6 minutes, anyway, and we just wanted coffee by this point -- but we left the beans whirling for approximately 14 minutes before sieving it this time.
9. The third and final batch of beans was a shade darker: an even medium roast; not ideal according to the tastes of our team of espresso fiends, but adequate.
The third batch.
10. We only ground the second and third batches. We only used a mortar and pestle because the electric grinder one of us owned was forgotten at home, which resulted in much effort and a large-grind size.
Addendum: as a fringe benefit, one of our parents heard about the mortar and pestle and gave us a coffee grinder as a Christmas gift. Science is fun!
11. The water went in the pot on high heat. The second and third batches were respectively brewed by hand-pouring boiling water through the grinds in our filter, and bringing three cups of water with the grinds to a boil thrice before filtering ("Turkish" method).
Mmmm. A transparent bit of the Turkish brewed third batch.
12. The second batch resulted in a light bodied tawny-amber coffee, with a mild flavour very reminiscent of suburban drip-machine product. The third batch was a light-medium bodied amber coffee with a more complex cocoa flavour. Both were judged good with cream and sugar by some members of the team, provoking a caffeine fostered second-wind of scientific debate on the subject of doctoring coffee. We doubtlessly drank it all.
Pop-roasting coffee beans is an entertaining way to spend a Saturday night, though no way to treat/produce stellar coffee. Since our experiment, we have heard rumours of more robust popcorn machines which do not lag/sag due to long runtime, and produce darker roasts.
For the sake of interest this is worth further inquiry, though recently, when while spontaneously toasting the last quarter of the beans in a small cast iron pan I heard a distinct snapping sound, I arrived at an ultimate conclusion: as the Ethiopians perfected pairing and preparing coffee and popcorn eons ago, any expectation of progress in this area is mere folly.
Posted by delire at January 5, 2005 02:15 PM