More and more people are no longer satisfied with just brewing and tasting—they want to control the entire process from green beans to roasted beans. But after buying green beans and bringing them home, many people have no idea how exactly to roast them, what tools to use, or how to control the heat. This article draws on the practical experience of Front Street Coffee to lay out practical methods for roasting coffee beans at home: how to judge roasting progress by color and cracking sounds, what first crack and second crack each represent, how different roast levels affect flavor and mouthfeel, and the pros, cons, and precautions of three tools—the rotating drum, the frying pan, and the electric oven. After reading, you will at least understand when to adjust the heat, when you can stop the roast, and why roasting too dark is not worth recommending.

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Coffee has long been part of many people's daily lives, and knowledge about coffee on various video platforms has become increasingly rich and systematic. Beyond studying brewing techniques and flavor identification, some enthusiasts have already set their sights on an earlier stage—roasting coffee beans themselves.

But enthusiasm is one thing; many people only discover after buying green beans that they have no idea where to start. Next, let's draw on the practical experience of Front Street Coffee to talk about how ordinary people can roast coffee beans at home.

Differences in taste by coffee bean roast level

For home roasting, you must use low heat in the beginning, then gradually adjust according to the situation. No matter which device you choose, you must keep the coffee beans constantly moving while closely watching the color changes of the beans. If the color changes come very quickly and not evenly across the whole batch, that usually means the heat is too high, or your stirring frequency cannot keep up. If you feel your stirring rhythm is already on point and cannot go any faster, then the heat is indeed too strong. At this point you should immediately turn down the heat and move the pan off the stove so the temperature inside the pan drops as quickly as possible. After it cools, put it back on the stove with the heat already adjusted and continue roasting.

Conversely, if the beans' color does not change for a long time—three to five minutes, ten minutes, or even longer with no reaction—then the heat is too low and you need to increase it appropriately. When the beans' color changes slowly and evenly across the whole batch, that means the heat is just right. At this stage, besides observing color, you can also pay attention to the sounds made when the coffee beans crack.

As roasting progresses, the beans gradually turn from their initial light green to yellow, then brown, then darker brown, and finally black. During the transition from yellow to brown, a cracking occurs, but this process is extremely brief and sometimes not obvious—it may stop after only three to five cracks. This is what is called first crack.

Then, during the stage from brown to dark brown, there is another cracking that can last two to three minutes or even longer, with sounds as dense as firecrackers popping—this is second crack. Second crack is very easy to identify. Usually, if you turn off the heat right when second crack begins, that is, after hearing about ten cracks, you get beans at a medium roast to full-city roast.

The characteristics of this type of bean are: a dry surface, not yet oily or with only a trace of oil sheen, and tiny black spots distributed across the brown bean body. If second crack continues, the roast level deepens accordingly. By the time the sound completely disappears—that is, when second crack ends—the beans are basically black all the way through and quite severely carbonized.

Of course, this also counts as a roasting style, and there are plenty of people who prefer a burnt flavor. Overall, from the beans turning golden yellow to later turning black, all of it falls within the normal roasting range. You can stop the heat at any point in between, and the coffee you roast will still be drinkable. When to stop is entirely up to personal preference.

Generally speaking, the darker the roast level, the more prominent the bitterness, the worse the layering of the mouthfeel, and the lower the nutritional value. Fully carbonized beans do have a distinctive flavor, but they really cannot be said to have much nutrition, so it is not recommended that everyone roast to this degree!!

What tools should be used to roast coffee beans at home?

Recommended—a rotating drum specifically for roasting coffee beans

The reason the rotating drum is recommended is that it is closer to how coffee beans are heated in a coffee roaster. When roasting beans with a roaster, the coffee beans enter the drum, and the machine rotates at a fixed speed of 60 to 65 revolutions per minute (the speed can also be adjusted according to the condition of different beans), allowing the beans to be heated evenly inside the drum and thereby ensuring consistency in the final product.

According to the personal experience of Front Street Coffee's baristas, there are two things to watch out for when roasting beans with a rotating drum: first, you must roast over low heat, otherwise the beans can easily change color on the outside while still being underdeveloped inside; second, turn on the heat and adjust the flame level first, then place the rotating drum on it and start turning it immediately, keeping the speed at 60 to 65 revolutions per minute.

The time required to roast with a rotating drum is more than double that of a professional roaster. For example, when Front Street Coffee uses a Yangjia 800n roaster to roast red bourbon coffee beans from the Cerrado region of Brazil, the time from first crack to discharge is 3:30, which is a medium-dark roast, with a total roasting time of 13 minutes.

This is the Brazilian Cerrado coffee beans that Front Street Coffee roasts with professional machines and sells

If you switch to roasting with a rotating drum, reaching a similar level requires a total roasting time of 31 minutes. During this period you also have to keep turning the drum nonstop (60 revolutions per minute). Once you stop or slow down, it is very easy to scorch... It is fair to say this is quite hard on the hands.

This is the same kind of coffee bean that a Front Street Coffee barista roasted at home using a rotating drum

Although roasting beans at home is very tiring, you can feel very clearly and intuitively how the coffee beans slowly turn from green raw beans to yellow, giving off a sweet aroma similar to corn, then gradually turning cinnamon-colored, releasing a caramel scent, then slowly turning chocolate-colored, giving off the smell of roasted nuts.

2. The simplest and most primitive method—pan roasting

Almost every household has a frying pan used for everyday cooking. During the long years before professional roasting equipment existed, coffee roasting relied on pan roasting. Of course, the results of pan roasting cannot be compared with those of a professional coffee roaster.

The main problem is that during stirring, the beans cannot roll evenly in the pan, resulting in uneven heating. But the advantage is a strong sense of participation! While stirring, we can watch with our own eyes as the coffee beans change step by step from green to chocolate brown. No matter how the final coffee tastes, it is a great experience.

To roast coffee beans in a pan, first clean the pan used for roasting coffee thoroughly and remove the grease on it. A household pan used for cooking over a long period will inevitably retain a lot of grease, so before roasting coffee you must wash it thoroughly! The usual method is to wash the pan, then turn on the heat to dry the moisture, then add water and boil it for a bit, pour out the water, and turn on the heat again to dry it! Repeat this once or twice.

Heat it until the moisture on the pan surface is dried off and no obvious grease can be seen! Turn on the heat and wait until the pan surface is dry with no water vapor, then add the green coffee beans! The amount should not be too much; 100 to 200 grams is appropriate! Whether you use electricity, gas, or another heat source matters little; the key is to control the heat well! This can be compared to other roasted or fried foods—the whole process requires moderate, stable heat.

3. Not recommended, but worth trying—the electric oven

Quite a few people also consider an electric oven. Ovens usually cannot stir the beans inside at all times. In this case, it is recommended not to roast too many beans at once, and also not to overlap or stack the beans—that is, spread the beans flat on a tray in a single layer. Then, according to color changes, take them out periodically and stir them to ensure the coffee beans are heated evenly.

The above content is compiled by CoffeeHunters, a coffee news website.