How do I Roast Coffee?

wiseGEEK Writer

A number of methods exist for people to roast coffee beans at home, and this practice is by no means new. Until the early 1900s, the idea of getting roasted beans from coffee suppliers wouldn’t have been particularly common. Instead most people bought green beans and roasted at home, but smart coffee dealers saw a market for providing this service. Now many people in the world buy their beans pre-roasted, and often pre-ground. However, home roasting is definitely coming back as an option for coffee lovers.

Ground coffee.
Ground coffee.

People can roast coffee in a number of ways that include oven roasting, stovetop cooking, or machine roasting. The oven roasting method often works best when people have a convection oven. Circulating air around the beans helps to ensure that they are roasted evenly and completely. However some people do use a simple gas oven. One proviso is that there needs to be a good working oven fan or vent in order to get rid of the smoke and steam that begins to rise from coffee beans cooked at high temperatures; the smell can be pretty overwhelming at first, too, though some people like it.

It's only after they're roasted that coffee beans turn brown and become usable for brewing.
It's only after they're roasted that coffee beans turn brown and become usable for brewing.

An additional recommendation for oven roasting is to buy flat pans that have multiple, small perforations in them. This allows for air to move through the pans during the roasting process. After roasting is finished, two perforated bowls like colanders can be used to quickly cool the coffee. Roast coffee will continue cooking when removed from the oven unless it is cooled.

Green coffee beans are ready to be roasted.
Green coffee beans are ready to be roasted.

Stovetop coffee roasting is an alternative method, best employed with gas burners. What is distinctly different is that the beans will burn if they aren’t moved constantly. Those who are very skilled with a skillet could pull off shaking the beans for the time it takes to cook them. Others recommend using a stovetop turning popcorn popper. The crank can be used on these to keep the beans in motion. This method takes less time than oven roasting but it is more labor intensive.

Lastly there are home roasting machines and many of these are considered excellent. Prices on machines can vary, but they can allow adjustments to different types of roasts so people can experiment. Of the three methods available the home roast machine is the easiest to use, though some purists suggest the pan roast method yields better coffee.

The main goal, when using green beans, is to roast coffee to a certain temperature, smell, and color, which may vary in time depending on roast method. Time to roast coffee is about 20 minutes at most in the oven and about five minutes on a stovetop. People can use thermometers to check roast coffee bean temperature.

There are also guidelines available on how to achieve different roasts and at what temperature these roasts should be. Color is another consideration that determines time length, since lighter coffee has a little less flavor and packs a more powerful caffeine punch, and dark roasts, have lower acid but strong flavor and less caffeine. The smell of the coffee is also important because as it shifts from green bean to brown or black bean, it begins to smell like recognizably roasted coffee.

Temperature settings for roasting coffee can vary. In the oven, they often exceed 500 degrees F (260 degrees C). On the stovetop, pan temperature may need to be just slightly under that. A coffee roast machine may allow people to set temperature or only set time, depending on its complexity.

Whole roasted coffee beans.
Whole roasted coffee beans.

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Discussion Comments


I had a friend who set up an actual gourmet roast coffee business in his basement. He formed a partnership with a local coffee importer who sold him large bags of green coffee beans from all over the world. He'd select one variety of coffee every morning and spend hours roasting that bag of green coffee beans. The finished product would be put into cans and shipped out to online customers that same day.

He told me there is a steep learning curve when it comes to coffee bean roasting at home. The difference between a light and medium roast coffee can be a matter of seconds. It was even harder to create a dark or Italian roast coffee without burning the beans. He said to listen for a cracking noise, which he called the "first crack". The trick for darker roasts was to wait for a "second crack" and immediately remove the roast coffee beans from the heat.

It was more art than science, he said, but it was a skill worth learning if you really enjoy fresh roasted coffee.


I've heard there's a way to roast green coffee beans in a modified hot air popcorn popper, but I don't know if the results are very reliable. I think you can get a light or medium roast coffee that way, but the beans won't get very dark. I think I'll just let other people do the coffee roasting for me.

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