Roasting coffee at home is really quite a simple concept however there is a huge margin for error. Whether you want cheaper or fresher coffee or perhaps the opportunity to experiment with different blends home roasting will most likely take some practice to perfect. Bear in mind, when you have developed your roasting skills a quality machine such as the Jura Capresso ENA 5 will still be needed if you want quality drinks.
The general premise for home roasting coffee in the oven is simple. You will need to be able to expose the beans evenly to air that is the temperature of at least 400 degrees for 5-10 minutes. You also must know the right moment to cool them. This might seem simple but it’s often hard to determine when to halt roasting also to prevent the coffee from unevenly roasting.
To start a new roast you will need a perforated surface that is oven proof such as a normal petal like vegetable steamer. Any type of pan with small holes in the bottom will do. The reason for using something perforated is so that the air currents can flow more evenly through the beans.
Layer a thin layer of green beans on the surface of your pan or steamer (if using a vegetable steamer you can fit a thin layer of approx. 3 oz. of beans). the green bean layer should be thin but can be 2 beans thick.
Your oven needs to be preheated to 425. Once your oven is up to temp place your green beans into the oven in a central location such as the middle of the middle rack. Go ahead and set a kitchen timer for 10 minutes. If you are trying to recreate a roast that you are fond of it would be helpful at this point to have a sample of that roast handy so you can use it as a color reference.
Shortly the coffee will start to release bound moisture because of the heat and you will start to hear crackling. After 1-2 min. of the crackling sound it is a good time to check on the shade of the beans.
Open the door of the oven and check the darkness of the beans, be careful not to take too long or your house will fill with stinky smoke. You need to check the color every couple of minutes until the color is slightly lighter than the shade that you are trying to achieve.
The reason you want to pull the beans before they are the final color is because they will continue to cook and darken while they cool. If you can place your beans in a protected area outside to cool so the smell doesn’t fill your entire house.
Don’t worry if your beans look a bit uneven or darker in spots than you were trying for. Your home roast will still taste better than any stale grocery store bought bean that is available.
Once a week I roast beans, let them cool and put them into my Jura Capresso ENA machine to use (I own the ena 5 cherry red… I love it).