Coffee roasting is the all-important chemical process, where we take the dried "raw" green coffee beans and transform them into roasted coffee products. It gives the beans the personality you enjoy in your cup of joe. Once you learn how to roast coffee beans, you have the power to create your desired color, flavor and taste of coffee!
Read on to find out how to roast your own coffee beans.
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Attributes of roasted levels
Whether you want the best light roast coffee, medium or dark roast coffee, there are processes you must stick to! But before I go there, let me tell you something about their attributes on different roasted levels:
Light Roasts
Light roasts have a toasted grain taste and are high in acidity and caffeine. This will give you your milder coffee varieties. As the name suggests, coffee beans roasted at this level are light-brown in color.
Medium Roasts
This roast is often referred to as the American roast, as maximum portion of coffee consumers in the United States preferred this one. It is medium-brown in color with a much stronger flavor and more body than light roasts.
Medium-dark Roasts
Darker in color, the medium-dark roasts will provide a bitter-sweet aftertaste. The beans have some oil on the surface and the aromas become more noticeable.
Dark Roasts
Dark-roasted coffee beans are almost black and are so oily that you can sometimes see the droplets on the surface in your cup. They give a smoky, or even burnt taste and the level of caffeine gets much lower.
Both medium dark and dark roasts are preferred throughout most of Europe and are found in espresso, Italian and French roasts.
Roasting at Different Temperatures - What's the Outcome?
The above outcome and taste of your coffee beans depend on the different temperatures throughout your roasting process. Maintaining the correct temperature and timing will result in the perfect bean.
Here I provide a quick guide to what happens at each stage:
Stages: |
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This is where some of the moisture is taken out of the coffee beans and you'll see steam rising from the roaster. This stage gives off a strong "earthy" or "grassy" aroma and is where the bean loses the green hue it began with.  |
The color of the coffee bean begins to resemble what we actually think of as roasted coffee beans. This gives the coffee a smell similar to baked bread. |
A little bit like roasting popcorn, you'll hear the first crack at this stage at about 355 degree F. This will tell you that the real roasting process has begun. As the sugars caramelize, you can start to smell the fragrant steam. The coffee beans will begin to expand in size and will be an uneven color.  |
The beans are now medium-brown and this is where your personal preference comes into play. The first crack signified that the roast can now be considered complete at any time. At this stage, only about 50% of the sugars have been caramelized. The coffee would have a rich taste if brewed in this state. |
Now we're getting somewhere! At this stage, the roast becomes darker, the beans become bigger and are being caramelized in full swing. The second crack is on its way at 415-425 degrees F. The beans release some oil, giving them a sheen. The coffee beans are now a rich, brown color and would be full-bodied with a sweet taste and strong aroma. At this stage, you’ll hear the second crack at about 430–450 degrees F.  |
This process actually eclipses the origin characteristics of the roast. The beans are now a dark-brown shade with a caramel flavor. The acidity has been muted. Beware not to roast too far after the second crack, as it could break the beans up completely! |
The roast becomes even darker, the sugars burn completely and the bean structure breaks down. This occurs at the end of the second crack. The bean becomes woody with burnt undertones. They'll be mildly sweet in taste with a weak aroma.  |
Misconception among Dark, Medium and Light Roast Coffee
If you know how to roast coffee beans, you'll know the process gives you those aromatic, brown coffee beans you love. But does the color of your roasted coffee beans affect any other properties?
Well, actually, it's a common belief that darker coffee beans are a sign of a higher caffeine content. In fact, it's the light roasts that will give you more of that caffeine hit you may be looking for in the morning. To get the same amount, you would need four shots to equal one cup.
Should you Roast your own Green Coffee Beans?
To make the best tasting coffee possible, you need to have the perfect roast. It’s important to consider what all goes into roasting when you will do it at home. Most home roasters are electric and have a heat source, a fan, something to keep it moving and a control. Unfortunately, it’s not as easy as scaling down the big rotary drums. There are issues with space and heat transfer.
However, roasting beans at home does have strengths. Like many at-home solutions, it is much cheaper than purchasing pre-roasted beans. Green coffee beans have a much longer shelf life than their roasted counterparts. The aroma of coffee you love comes out in full strength when you home roast. You can truly enjoy the scents and the process. The only drawback is the smoke it produces, which may have your smoke detector shuttering at.
If the Maker doesn't know properly how to roast coffee beans?
Even if you know how to roast coffee beans, it can go wrong at many steps. To prevent the beans from overbaking or burning, beans need to be heated at a descending pace. The higher the temperature, the slower the heat grows. You need to make sure to start with a high heat which is best achieved by preheating the pan. If you let it rise too quickly, the beans get too hot and over-roast.
Try to roast again if it goes wrong.
The best solution if it goes wrong is to toss out the batch and try again. Even professional roasters have to throw out batches. Let the smoke clear out of the kitchen with a fan and try again. If you are determined to roast at home, you have to stay determined. It may take a couple tries, by when you get it right, it’s sweet. Roasting coffee is an acquired skill and it takes time. Perfecting any art requires you to try and fail.
The bottom line
As long as you don't go too far into that second crack in the process and obliterate your roasted coffee beans, you should be okay! Coffee Crossroads found that those on the West Coast of America have traditionally preferred darker roasts, compared to those on the East Coast.
Which side are you on?
Whether you enjoy your coffee to taste bitter, rich or grainy, you can create your perfect cup during the roasting process.
