Home roasted coffee is a good argument for scratch-n-sniff photography.

For 10 minutes worth of work, you can have the best damn coffee you’ve ever put in your mouth. No, I’m not exaggerating. Coffee I used to rave over at the local cafe where they roast their own now tastes like swill since I’ve learned to roast my own. The main reason is that coffee begins to lose its flavor after it’s roasted; only seven days after roasting the taste is seriously deteriorated.

There are different methods to roast coffee. You can buy a home roaster, but those cost about $90 and are a waste of money in my book…use that dough to buy a lot of coffee. You can roast the beans in a popcorn popper, either an air-pop style or a stove-top model. I own neither but once you learn the physics behind roasting you’ll be able to adapt roasting to the popcorn popper easily. Here I’ll show you how to roast coffee in a skillet and in the oven (watch a video of this here). 

Green coffee can be purchased from different sources. I get mine from Camping Survival. Their organic green Costa Rican Monte Crisol coffee beans (available here) are canned so I can buy in bulk and they keep on a shelf until needed. After I open a can, I keep the green beans in the freezer until I’m ready to roast a batch, which I do twice a week or so. How often and how much you roast depends upon your own personal needs, but don’t roast less often than once a week or you’ll defeat the purpose of home roasting. One guy I talked to roasts his coffee every evening, ready to grind the next morning when he wakes up. Roasting only takes about 10 minutes, so this is the ideal scenario.

SKILLET ROASTING

A heavy skillet, be it cast iron or heavy stainless steel, is necessary since high heat is needed to roast coffee. And take note: roasting coffee is smoky business, especially if you like darker roasts. The longer and darker the roast, the smokier the process is because you are caramelizing the beans and burning off more and more sugars. Make sure you have your kitchen vent set to high. A window fan doesn’t hurt, either.

To roast in a skillet, place the skillet on the stove (or a hot grill outside) and heat on medium until it is hot. Do NOT put any oil or anything else in the pan; coffee is roasted dry. Dump the green coffee into the skillet and start stirring using a whisk. You’ll need to stir constantly to keep the beans moving for an even roast.

Stir until your desired level of roast is reached, turn off the heat, and immediately dump your beans into a colander. Shake the colander to cool the beans and remove the papery chaff from the beans. That’s it…your done. You can either grind all of the beans immediately, or just what you need each morning. It’s up to you.

OVEN ROASTING

This is easier in many respects, but I prefer the taste of stove top roasted coffee myself. Try it both ways and see which one works for you. For this method, just heat your oven to 500F. Place your green coffee on a heavy duty cookie sheet with plenty of space between beans. You’ll still only want to roast smaller quantities at a time even though your cookie sheet can hold much more; the more coffee you roast, the smokier it is.

After your oven is fully heated, pop the beans into the oven and wait. You’ll have to experiment a little bit with your oven and determine how long it takes for the beans to reach your desired roast. In my oven it takes about 15 minutes to get a very dark roast, which is what I aim for.

Once your desired roast is reached, remove the beans from the oven, dump them into a colander, and shake to remove the chaff and cool the beans. Then you’re done! As with stove-top roasting, you can either grind it all at once or grind each morning. It’s up to you.

THE PHYSICS OF ROASTING

Coffee roasts best between about 375F to 540F and there are several stages coffee goes through while it is being roasted. You’ll quickly learn what these stages are and be able to customize your own roast based upon what you hear, see, and smell.

“First crack” is the auditory signal that a very light roast has been reached.

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The “first crack” occurs at about 3 to 4 minutes. Here the sugars will start to caramelize causing some smoke to appear, and steam starts to escape. First crack indicates a very light roast, which is rarely brewed into coffee but it’s your coffee, so you get to decide on your own whether you like it.

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Second crack indicates that a Full Medium Brown or City Roast has been reached.

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The “second crack” can be heard at about 6 minutes, and is louder than first crack. At this stage you’ll also see the beans jumping around a little bit as the steam escapes; sometimes a bean will explode like popcorn. At second crack the coffee is considered a Full Medium Brown or City Roast. Still not dark enough for me but  this is a common roast for people to drink.

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The roast darkens after this and develops a wonderful oily sheen; at what stage you want to stop roasting the coffee depends upon how dark a roast you want. But be careful, over-roasting coffee can burn it, and then it tastes like charcoal.

I stop roasting at about 13 minutes using the skillet method, when the coffee is a dark roast and shiny. This would be a French or Espresso Roast. Or maybe the Rural Spin Roast. If you like a darker roast, try going a minute or two longer as the beans darken and get even shinier to see if you like that taste; this Dark French or Spanish roast is not readily available in the United States, but is in parts of Europe and elsewhere.

At about 13 minutes, the Rural Spin Roast has been reached…aka a dark or French roast.