How to Home-Roast Green Coffee Beans

Home roasting raw, green coffee beans is really not that difficult and, the end result is quite good, often the same as commercially roasted coffee.

What are Green Coffee Beans?
Raw, Unroasted Green Coffee BeansGreen coffee beans are raw, unroasted coffee beans. There are so many different types of sophisticated green coffee bean roasters on the market today which roast consistently, evenly and with little time and effort. If you're not sure about investing in a luxurious roaster right away, you can always try roasting green coffee beans in a skillet or a popcorn popper (which is what I tried before investing in i-Roast Coffee Bean Roaster). Whatever you use, skillet or popcorn popper, make sure your equipment is very clean otherwise your coffee will be "seasoned" with a either a buttery smell (yuck) or with whatever you last used the skillet for.

Interestingly, green coffee beans roasted lightly contain slightly more caffeine than darker roasts. However, the darker roasts don't have that acid taste of the lighter style. Needless to say, use high quality green coffee beans!

The green coffee beans should be heated between 460 and 500 degrees Fahrenheit (see table below), so don't be alarmed when it starts to smoke. Turn on your stove-top exhaust, or open the windows for cross ventilation, or a fan works too. If this is your first time home-roasting, be aware that in addition to the smoke, there will be also be an odor that happens with the roasting process so persuade family members to enjoy the outdoors for a bit while you air out the house.

Temperatures of Roasting in Fahrenheit and Celsius

Fahrenheit Celsius
Green Coffee, Unroasted, 75 23.88
Begins to Pale 270 132.22
Early Yellow 327 163.89
Yellow-Tan 345 173.89
Light Brown 370 187.78
Brown 393 200.55
1st Crack Starts 401 205
1st Crack Done 415 212.78
City Roast 426 218.89
City+ 435 223.89
Full City 446 230
Full City+ 454 234.44
Vienna (Light French) 465 240.56
Full French 474 245.56
Charcoal, dead 486 252.22
Fire risk 497 258.33
Visual Guide to the Roasting Process

Put the green coffee beans in the roaster and crank up the heat. It would be a good idea to disable your smoke alarms. Many roasting machines come with a built-in thermometer, which is very useful, but if you plan on using your skillet, purchase a thermometer made for making candy.

As you start the roasting process, your green coffee beans will first turn a pale, yellowish color and, then finally, some shade of brown. However, the shade of brown depends on how dark of a roast you prefer which is always on an individual preference.

While the green coffee beans being to heat, a combination of oil and water appears, which puts pressure on the surface of the bean and you may hear a loud crack. This is to be expected, perfectly normal, so do not panic. You will hear this sound sometime after four to seven minutes of the heating process. Make sure to stir constantly during this crucial time.

As the roasting progresses, the natural sugar inside the coffee bean will begin to caramelize. However, it's up to your individual taste buds to the extent of the caramelization. Make sure to check the color every thirty seconds.

If you plan to roast your beans long enough because you prefer the taste of darker roasts, then you typically hear a second loud cracking sound. By this time, the coffee beans will be very dark. Please keep in mind that roasting beyond the second loud crack is just burning the coffee, which doesn't add much to the flavor and usually makes it taste too harsh.

After you're done roasting, pour the beans into a colander to allow for cooling then agitate them. Along with the beans, you will see a thin, skin-like peel called the chaff. The chaff either needs to be removed during the roasting process or after it's done with a mesh cooking screen.

To discover what your taste buds prefer, experiment with different batches of different types of roasts with different types of green coffee beans. Please be aware that even though you've stopped the roasting process, the heat trapped in the bean will continue to cook it for awhile, so stop just a little before the desired roast. With some trial and error and lots of fun, you will be drinking the freshest, most delicious cup of coffee or cappuccino. Enjoy your freshly roasted coffee after 4-24 hours of resting, which enables the CO2 to de-gas. Also, see my post on storing freshly roasted green coffee beans. Good luck, enjoy and have fun!!


2 Responses to “How to Home-Roast Green Coffee Beans”

  1. Joseph on November 9th, 2010 1:01 pm

    Really informative, particularly the roasting chart, it takes the guesswork out of it.

  2. useful on January 5th, 2011 11:45 am

    Not long ago i had to cut down on my personal coffee / espresso consumption however this excellent page helps make me to prefer I had not!

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