Spin Test – Green Coffee Rotation in Popper

To get even, quality roasts, you want to be sure the green coffee is rotating in the roast chamber! This quick video demonstrates how…

Overloading the Popper roast chamber will mean the coffee on the bottom will scorch and burn, while the coffee on top will be under-roasted.

To find the best batch size for you, you can test the rotation visually over the first 30 seconds of roast time. Here are examples of insufficient agitation, and very good agitation. Once you find the best batch size, weigh out your coffee on a gram scale for every roast! It’s the way to get consistent results. 

Spin test for green coffee rotation: A quick video demonstrating bad agitation and good agitation levels of green coffee in the Popper coffee roaster

Ideally, in an air roaster you will see coffee not only rotate, but also “bubble up” from top to bottom as the coffee loses mass, initially in the form of water content.

And by the way, this applies to all other air poppers and roasters that use centrifugal air movement.

#poppercoffeeroaster , #aircoffeeroaster, #homecoffeeroasting #popperisacoffeeroaster

4 Responses

  1. The coffee will get lighter as the roast proceeds. If the coffee isn’t spinning when you first start roasting you can stir it with a long-handled wooden spoon for the first minute or so to help prevent burning. Then when the coffee sheds some of its water weight it will start to spin on its own as the roast proceeds.

    1. Good advice Jim! I find that even a little movement at the start of the roast promises sufficient rotation about a minute in as the coffee loses water, like you said. I too love the coffee access your afforded by roasting with the lid off.


  2. I’ve been roasting in a popcorn popper for close to 10 years now and my favorite way to roast is just adding the beans in quickly till it just barely stops spinning. I help the beans along with a stick until enough steam escapes for them to rotate by themselves which is probably only 5 seconds in. Also, I allow the popcorn popper to run about a minute before adding beans. First crack can be weak if the popcorn popper isn’t warmed up, not good. In the past I used a scale like in the video but it seemed there was different variations in spinning based more on shape and size of bean over weight.

    1. All sound observations, and I usually opt for a simple “fill til it stops moving” method myself, rather than weighing!

      Thanks for sharing your experiences with the Popcorn Popper. It’s amazing how many different ways you can impact roast with such a simple machine.


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