Air Roasts – Closeup on Roast Levels

Learning about the air roast process, like the Fresh Roast, Air Popper Roaster, or West Bend Popper, by looking closely at roasted coffee results

No matter how you look at it, roasted coffee is brown. Light roasts are a lighter brown and dark roasts are a darker brown but depending on a few factors, it can be hard to tell the difference between roast levels.

An air roast, meaning the coffee is moved around in a hot air stream and not physically turned in a drum, has a different set of issues, positives and negatives. Positive is that the roasts tend to be even, the heat transfer is uniform, and it is hard to scorch coffee. The down side is the possibility of not roast coffee evenly from the outside to the inside of the bean.

Since the surface of coffee beans absorbs light, the type of light you look at coffee with really matters. We like to look at coffee under daylight balanced LED.

Some things to look for are the texture of the beans, how much they have expanded during the roast, how rounded the flat side of the bean has become, how shiny or matte the surface is and how much the crease of the bean has opened up.

Note at 7:10 the subtitle mixes up Left and Right. Thanks for pointing this out Gary !

Also see: Using Sight to Determine Degree of Roast and Need a Visual Guide to Determine Coffee Roast Color?

6 Responses

  1. RE: Air Roasts: Closeup on Air Roast levels
    In your comments of close-up shots comparing left and right beans, I believe you have them switched – seems to be all of those pics- perhaps the images got flipped?
    The more roasted ones are on the right , bit you call them left and vice-versa.

    1. Thanks for pointing this out. I am looking for that in the video now and will correct it!

  2. I know this video is a few years old, but I’ve kept coming back to your info on air roasting since I recently transitioned to an air roaster after using a Behmor for nearly a decade. I know that air roasters are generally faster than drum roasts or other methods, but can you give any advice on how to deal with coffees that have some age on them, specifically in air roasters? I still have some Xinabajul Producers on hand that has been stored well, but it is really taking off around first crack. A batch intended to be a City roast ended up coming out at Full City! It still tastes great but I had trouble trying to rein it in. Appreciate the knowledge and insight you share with us!

    1. Hi Dustin, thanks for the comment, and glad to hear this article has been helpful!

      If your roaster has manual heat control and thermometry, I would try pulling back on heat before your normal 1st C temp. You might even start off at a slightly lower temperature to extend the overall development time, and keep the fracturing stage from being too violent, and getting away from you.

      What roaster do you have?

      Thanks again Dustin.


    2. Thanks for getting back with me, Dan. My roaster is a Kaffelogic. I was a backer for their Indiegogo campaign and have been learning the machine since receiving it a few weeks ago. I really like that it’s a “best of both worlds” kind of roaster–some well-designed built in roast profiles and repeatability, but also allowing me to make changes to just about everything in a roast (power, fan speed, etc.) within its software and the PID giving some real-time feedback during the roast.

      I’ve been using the Kaffelogic’s built-in “altitude” profiles to get a feel for the machine–these profiles determine things like fan speed, heat, etc. at various points in the roast based on the altitude range at which the coffee was grown. It’s not perfect, but it does give a general starting point to go off of. I used the 1500-2000m profile for my last batch of Xinabajul, but considering it has a bit of age on it, I may try the next altitude band down, which has an overall gentler start. I think that Kaffelogic profiles also allow adjustments to the amount of power at the beginning of the roast, so I may try that as well. Thanks again for getting back with me!

    3. You bet Dustin!

      I think your intuition about a gentler ramp is spot on given that is not a ‘fresh’ arrival. That said, it’s still cupping great (hope you agree!)


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