A “spin test” means finding the right batch size your Popper roaster. It can vary due to voltage and other factors.
Watching the green coffeeGreen coffee refers to the processed seed of the coffee tree fruit. Coffee is a flowering shrub that produces fruit. The seeds of the fruit are processed, roasted,... ...more spin when you start up your Popper roast is important. The coffee should rotate and slightly bubble, and you know you have the right batch size. Even a few grams of coffee could make the difference. But I have found it hard to tell people EXACTLY what you should be looking for. Perfect situation to communicate this in a video!
The fan in an air roaster needs to do 2 different things at the same time: transfer the heat to the coffee to roast it, and keep the coffee moving in a way that it won’t scorch. Too little air movement and the coffee on the bottom near the heating element will burn, resulting in a scorched skunkySkunky is a defect term related to improper roasting; tipping or scorching of coffee. It relates to a lack of sweetness, a presence of bitterness, and a particular... ...more roast tasteThe set of flavors that result from the degree-of-roast.: Roast Taste is a term we started to distinguish it from "Origin Flavor". We use the "roast taste" term... ...more, and an uneven batch. But too much air flow creates a different problem: the hot air blows by the coffee and out of the roaster, resulting in under-roasted coffee.
You want to find that perfect balanceSuggests a harmony and proportion of qualities, and implies mildness since no one quality dominates.: Balance is both an obvious and slippery taste term. It implies a harmony... ...more, and once you do, use a gram scale to use exactly the right amount of coffee to get consistent roasts. Besides the green coffee batch size, other factors come into play. The voltage level (and more importantly, voltage drop once you start the roaster) play a big role that I demonstrate a bit in the video. Other factors like ambient temperatureThe temperature in a given room or space: This term is used to describe the overall temperature in a given environment, and is an important variable in coffee... ...more and even altitude matter.
The information here can be applied to other coffee roasters that spin coffee, as well as those that don’t. Batch size and line voltage matter!
Hopefully this video guides you to understanding the variables with the Popper, or other air roasters. If there’s something I missed or left unclear, please comment so I can address it.
4 Responses
Can you expand a bit on how altitude affects the roast?
I live at about 5500 ft in a dry climate.
Thank you
Hi Robert, great question, and I’ll be honest that I need to do a little more research on this myself. I would expect that lower temperatures are needed to push the roast at higher altitudes due to lower air pressure than at sea level. Same with baking, or boiling water. For the popper, this may mean that having a little more movement in the bean mass isn’t such a bad thing since the coffee can be roasted with a little less heat. I’m sure it really depends on how high up you are. I would start with the baselines Tom laid out, and then adjust as needed. I wouldn’t expect needing any drastic changes to compensate.
-Dan
Great to consider- I recently roasted 90g of a Pacamara and the bean tumble got a bit challenged toward the end of the roast. Have shifted to 85g for that type of bean to give the bean expansion a bit more headroom.
Yes Pacamara definitely need special consideration!