Home Roasting – Part 3

2010 July 8

We have tried the somewhat expensive but very flexible and controllable HotTop roaster. It is perhaps the ultimate home roaster and is able to produce coffee reliably at the same quality level as a good commercial drum roaster. What if all you have is a $20 bill in your pocket? Is home roasting a realistic option? The answer is “yes”. You’ll give up some control and ability to do profile roasting, but it is possible to achieve excellent results. The roaster for you is the humble hot air popcorn popper.

I chose the Cucina Bella available at Macy’s for $19.99. There are many others to choose from, but this particular model has some excellent features.

The best feature of this popper is the roasting chamber. It is the “swirl type” with slotted vents around the bottom of the chamber walls. This creates a swirling motion and helps blow chaff out of the roasting area. The other common style of popper has a central hole covered with screen, which I refer to as the “jet type”. It shoots a jet of hot air straight up through the green coffee beans and tumbles them. It is not quite as effective as the “swirl type” and, according to Sweet Maria’s, is much more likely to have a chaff fire. Another nice feature of the Bella Cucina is an ON/OFF switch, which is often absent in inexpensive poppers.

Before you begin roasting, it is important to gather the necessary tool. In addition to the popper, you will need a bowl to catch the chaff, a sheet pan for cooling the beans and a hot mitt or pot holder to remove the top of the popper. Set the chaff bowl under the spout of the popper.

You then measure out the correct amount of green coffee using the scoop provided. The popper uses the same volume of green coffee as popcorn kernels. This is about 1/3 of a cup or 75gr. Using the correct volume of beans is critical to obtaining a good roast. The fluidized bed is a balance of airflow and mass. Since the airflow of the Bella Cucina is fixed, the mass of the beans must be carefully standardized, as well. This sounds like a small amount of coffee (you will end up with about 60gr), but it is sufficient for a good pot of coffee or about 8 shots of espresso.

Dump the green coffee into the roasting chamber and put the clear grey air chute on top. It will direct the hot air into the chaff collecting bowl.

Turn the popper on. Immediately the beans will begin to swirl. This roaster is much faster than HotTop or a commercial shop-scale drum roaster. The roast time is 6 to 7 minutes versus up to 18 minutes, so you need to watch carefully. All of the sights, smells, and sounds we discussed in the previous post on the HotTop occur here, just much more quickly. Soon the beans are yellow, then cinnamon with the attending aromas.

Around first crack, the chaff blows off of the coffee and collects in the bowl. This occurs 3 to 4 minutes into the roasting process. After a period of the beans continuing to darken, second crack begins and the roasting process accelerates madly. Be prepared to end the roast and “cool” the beans!

Turn off the popper, take the top off  and dump the coffee onto the sheet pan. This is obviously a very crude way of ending a roast and cooling the coffee, but it works!

After a couple of minutes of shaking the roasted beans on the sheet pan, they are cool to the touch. As you can see, the popper did a good job of bean development and the consistency between beans is not bad. Once cooled, let the beans rest for a day before making brewed coffee and two or three days for espresso.

The next day, I tasted the Guatemala Finca San Diego Buena Vista that had been roasted in the popcorn popper. The cup quality was quite good. It was a bit brighter than the same coffee roasted in the HotTop and perhaps a bit less complex. Chanelle Richardson (the project photojournalist) also tasted it and thought it wonderful, as well.

So there it is! You can do a good job of home roasting with an investment of $20. Why not give it a try? In my final post on home roasting, next week, we will be doing a Roast Fest using four different home roasters with the help of a guest roastmaster.

4 Responses
  1. July 9, 2010


    I’ve really enjoyed reading this series. Thanks for all of the great posts.

    • July 9, 2010

      Thanks, Kyle. You are in a city with some of the best coffee roasters in the country. Even so, it is fun to roast at home. Thanks for reading the blog and feel free to comment at any time. Enjoy PDX, it’s 110F here today.

  2. Nicole Reeves permalink
    July 16, 2010

    Interesting project. I had never seen “green” coffee beans. The pictures are beautiful and really make the post come alive!! Thanks!

    • July 17, 2010

      Thanks, Nicole. Coffee is a very interesting product and photogenic. The coffee cherries themselves are probably the most visually stunning. I have enjoyed working with our photojournalist, chanelle richardson, as she has brought the project to life, visually.

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