Roasting Green Coffee Beans on the Grill

Most people that have thought of roasting their own Coffee Beans look at special roasters for doing that. I know because we did that for several years. Because we seemed to go through a roaster every year or so and we couldn’t justify paying several hundred dollar for a more commercial like roaster, we kept buying a new roaster. They would always go out right after the warranty period.

That changed when I got a new charcoal grill a few years ago. I saw someplace on the Internet about a guy roasting beans on his grill, (if I could find it again or remember where it was, I would give him credit for the idea), and thought it was worth a shot.

First to entertain the idea of roasting your coffee beans on a grill, you need to have certain characteristics on your grill to do it most effectively. First off your grill needs to be able to maintain a temperature of around 550 – 600 degrees Fahrenheit. In effect the grill must be capable of becoming an oven. I don’t want to go on and on about details and examples of what will work and not work because I think it would be more effective to talk about actually Roasting green coffee beans on the grill than provide a detailed tutorial.

What I roast the beans with is what has been called “Bubba Keg”, “The Big Steel Keg”, and “The Keg”. There will be pictures of it in this recipe but you can look it up on the Internet too. It is a Kamado style grill. There are many others out there that are that style but when I did my research, the one I have worked best for me. One of the key features that did it for me was that it was steel inside and out, with oven insulation in between the layers of steel. You can crank it up to 800 F and hold your hand on the outside of it. Several of the other makers the body is ceramic and therefore can crack. But back to roasting…

The detail steps are in the recipe but let me hit on some overall things that for me make the process simpler and more efficient. I found a Wok that fits perfectly inside the Keg and just has handles on the sides of it. With this as the roasting vessel I can preheat it in the Keg and keep the lid closed except for stirring. I also have a spatula for the Wok, you know it has a curved edge that fits the rounded angle of a Wok. That helps in a more efficient stirring as you want to stir as fast as possible and close the lid of the Keg again. You will lose 50 – 75 degrees in a quick stir.

I also have two oven gloves, as I like them better than mitts, I seem to have more control with gloves. These gloves are used both for the stirring process as well as the cooling process. I also have 2 fairly large wire colanders for cooling the beans.

With the oven gloves I can put one on, lift the lid and hold the edge of the Wok while I give it a quick stir, and then put the lid down again.

My target roasting temperature is 550, and when I get the Keg and the Wok up to 550 – 575 I put the green beans in to roast. When I stir the temperature will drop to 475 – 500 and will start heating back up after I close the lid of course. Then I wait until the temp is back up to 550 and maybe give it a quick stir again. You can roast a batch of beans, and for me that is about a pound of beans, in 15 – 20 minutes. You will start hearing the crack of the beans as you go and it will get to the point of sounding like pop corn. As the process goes you will also see more and more smoke – that is normal and it is no worry if you give your beans a good stir while roasting, so they won’t burn.

When I like the look of the roast I take it off the grill and set it on stone or concrete while I get ready to cool the beans. I use both oven gloves and the two colanders. I dump the beans into one colander and hold the other one in the other hand. I walk into the yard and pour the cooked beans back and forth between the two colanders. I keep a fair amount of space between the colanders so that the beans with catch the air and the chaff will drift out of the beans. These beans are still cooking when you take them off the grill and are about 500 degrees, so be very careful in handling them. But you need to cool them fairly quickly so the stop cooking.

After you have cooled the beans leave them in a colander on the counter for about 24 hours. The reason for that is they will emit gases for about that time, then you can put them in a container and start making coffee.

Here is a series of pictures from beginning to end of the roasting process:

Some random notes…
Green Coffee beans can be stored for up to 2 years in a cool dark place.
Roasted beans should be used in a week or maybe two weeks. I seem to roast once a week.
My opinion is that a lighter roast like say medium, can be done once you master the roasting process. But we prefer the dark roast.
You can order green beans on line from many sources and you will find that it is FAR cheaper and much better quality, and so much fresher than you can buy.
We don’t care to get fancy and mix various beans and make a blend. We just find a type of been we like and roast it. You can change the flavor just by changing the bean you are roasting.