Roasting coffee at home is an art that has been gaining popularity with coffee enthusiasts in the last decade. Because we have realized that roasting your coffee is a satisfying experience which gives us a better-tasting coffee –there’s nothing that can ever compare to brewing freshly roasted coffee, nothing– and it saves a lot of money for those people who consume obscene amounts of coffee. That’s you and me.
Before we begin our guide, I’m going to explain a few roasting-related terms first:
- Pungent-Pungency is the term used to describe the bitterness that is particular to the dark roasts of coffee. This is quality that is desirable in dark roasts but avoided in lighter ones.
- Baked-We use this word to refer to coffee that has been “overcooked”: if a roast is held for too long at inappropriate temperatures, the resulting coffee will be without any particular taste or aroma; flat, bland coffee.
- Bready-It’s used for coffee that was either not roasted long enough or wasn’t allowed to reach the appropriate temperature for all of the oils in the coffee bean to come out. The result is a bread-like taste.
The Roast in Four Acts
The first act is divided into two phases: During the first one –commonly referred to as the “drying” phase- nothing happens in terms of flavor and aroma: the beans are still building up heat, and only the surface reaches enough temperature for it to acquire a lightly roasted color. During the second phase, the magic starts to happen: sugars begin to break down, and the beans release steam and begin to expand, emitting pleasant aromas.
At the very end of this act, the chaff starts to come off the beans as the temperature rises, and we begin to see smoke. It is essential to ensure a good flow of air now to allow chaff and smoke to exit the machine properly.
The second act starts with the sound of the first crack. The beans will begin popping one by one and then be joined by the rest of the batch.
This chorus reaches a peak and eventually dies down, giving way to the third act: Bean oils are now migrating from the inside of the bean to its surface. With them comes another wave of carbon dioxide. Which is known as the second crack.
Fourth act: Development time. The last act of the roasting process is a bit tricky. Some people talk about development at any point after the first crack. This all depends on what result you’re after.
Development time is crucial for smokier, more abundant coffee flavors, but tends to be overdone and ruining the qualities found in lighter roasts; don’t extend the roast time for no reason or it will result in baked coffee.
By consensus the lighter of roasts, this roast gets its name from the resulting color of the coffee beans. To achieve the cinnamon roast, the beans are dropped (discharged from the roaster) very early after the first crack. Cinnamon roasts are usually described as having a particularly nutty flavor, with grassy aromas and very light body. Check out more light roasts in “What is the Best Light Roast Coffee?“.
The city roast is just slightly more roasted than the cinnamon roast, but the difference is immense. A very popular roast, city roasts are characterized by a sweet, winey taste with hints of caramel. Light bodied and acidic.
Full city roast
This is half-way between lighter roasts and darker roasts. It is the most well-balanced of all roasts, having qualities found at each end of the spectrum without taking any sides. To achieve full roast, beans must be discharged just before the second crack.
This roast offers a medium body with a slightly more pronounced caramel flavor than the city roast. Moderate acidity.
Now we begin to enter into darker territory. The Viennese roast is dropped sometime early after the second crack. In this roast, we find a bittersweet taste combined with nutty and caramel flavors. Heavy body.
The taste of actually roasted bean now makes its way into our cup: with coffee made from these roasts, we can start to perceive burnt, smoky flavors in our coffee. There are hints of caramel, and the body can be heavy or medium if roasted a little too long.
Want more info on the famous french roast? You’re in luck! Check out our piece on it called “What is French Roast Coffee?“.
This roast offers a pungent, bitter taste that only the darkest of souls can endure. It can be described as having a medium body and exceptionally oily. Sweetness is almost non-existent. For more on the Italian roast, check out “What is Italian Roast Coffee?“.
How Much Coffee Are You Going To Roast?
We’re almost ready. Now you’re going to have to plan your roast. How do we go about planning a batch?
Roasting machines usually advertise a specific maximum capacity. However, it is well-documented that these can be exaggerated: A good rule of thumb is to go for 50 to 70 percent of the maximum capacity of your machine. This will save you issues with overheating and minimize fire risks.
Air to Fuel Ratio
The flame of your roaster should look blue with orange streaks. Too little air results in a yellow-colored flame: You don’t want your flame to be deprived of air because it will produce more soot than it should. Allow for the flame to be on for a few minutes before you judge it by its appearance; it can take a moment to stabilize.
Refers to the temperature of your machine before you’ve loaded any coffee beans. These vary depending on what roasts you want to achieve, so it’s essential that if you’re going for a light roast to have a lower charge temperature than you would normally. Reasonable charge temperatures go from 193 to 227 degrees Celsius.
For charge temperature, it is essential to take into account batch size and bean density. If your batch is too big, adjust the charge temperature accordingly. And the same must be done if your green coffee beans are of higher density than usual (or lesser, although this is less common).
Have an approximate figure according to what roast degree you want to achieve. For classic drum roasters, the roast duration can go from ten to sixteen minutes so plan accordingly.
Planning makes all the difference when roasting. Remember that this is something you have to do with extreme care, you’re literally playing with fire. Plan your batches with care to avoid overheating or any other sort of problems; remember to clean your exhaust pipe regularly as well, so it doesn’t become clogged.
Now you’re ready to begin roasting: You’ve planned your batch, you know what roast degree you’re aiming for, and you’re ready to go. A couple of tips just before you jump into it. Warm up your machine for at least 20 minutes before every batch. This will keep your batches consistent and try always to roast the same amount of coffee beans, so you don’t have to adjust your machine to different settings every time. Remember that the key to good coffee is consistency.
Once you’ve roasted a few batches comes Cupping, my favorite part.
Cupping is the international standard for evaluating coffee. All the special equipment you need is a grinder and a scale. Apart from that, what you need can be found in your home: A kettle for boiling water, a few glasses, a spoon, a spitting bowl, and a timer.
This is how it goes:
- Boil water in the kettle.
- Grind 10 grams each coffee you want to try into a separate container each. The grind should be either fine or medium-fine.
- Now you take turns smelling each sample. Write down the differences between each of them; what you like and what you didn’t like. These notes will help you improve as a roaster.
- Once the water boils, let it sit for a minute and then start the timer before pouring the water. If you’re using a scale, pour approximately 170 grams of water.
- Once the bloom is stable, get close to it and smell again. This is when the aromas of your coffee peak. Write down every possible detail that you can think of.
- Do the same with all the containers. Let sit for 4 minutes.
- A crust will have formed at the surface: use a spoon to break it and stir very gently. Try smelling all the aromas again and then begin removing as much of the coffee grounds as you can from each container.
- After 9 minutes, you can start tasting each coffee with your spoon. Some people spit, some of them think that’s gross: it’s up to you.
I recommend letting your coffee cool enough so that your tongue is not distracted by the coffee being too hot, cold coffee is ideal for the discerning taste.
Don’t miss out on “Coffee Cupping for Beginners (Tasting Guide)“. A full guide to cupping for beginners.
After the first tasting, you should stop to take notes about each coffee. These notes are probably going to be scarce at first, but you’ll learn to express yourself as you gain experience. After about twenty minutes, you can perform a second tasting and revise your notes.
To make it even more fun, you can label the bottom of each bowl when you pour the coffee in and then shuffle them, so you don’t know which coffee you’re tasting until the end. This will keep you from playing favorites or being biased! Try it!
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We’ll brew ya later! ☕️