I believe many of you not only enjoy drinking coffee but have also become interested in coffee roasting. Front Street Coffee often sees people sharing their home coffee roasting process on social media while browsing online. However, we also notice that some people's roasted coffee beans end up uneven in color, with some lighter and some darker.

The roast level and uniformity of coffee beans determine the flavor expression of the coffee. Therefore, understanding the impact of roasting on coffee beans is extremely important. Before explaining the roast levels corresponding to coffee bean colors, Front Street Coffee will briefly share how to roast coffee beans at home.

Currently, there are many strange methods for home coffee roasting online, such as pan-frying, oven roasting, air frying, and so on. However, with these tools, we cannot ensure the coffee beans tumble fully and heat evenly at all times, so Front Street Coffee recommends purchasing a drum-shaped coffee roasting mesh.

When using a drum for roasting coffee beans, based on the personal experience of Front Street Coffee's baristas, two points need attention: use low heat for roasting, otherwise the coffee beans will very easily change color on the outside while still being raw inside; after turning on the heat and adjusting the flame size, place the drum on and start turning it immediately, at a speed of 60-65 revolutions per minute. Roasting with a drum takes more than twice as long as with a dedicated roaster. For example, when Front Street Coffee uses a Yangjia 800n to roast Red Bourbon coffee beans from the Cerrado region of Brazil, the time from first crack to discharge is 3:30, resulting in a medium-dark roast, with a total roasting time of 13 minutes.

This is the Brazilian Cerrado coffee beans roasted by Front Street Coffee using a professional machine.

When using a drum to roast to a similar level, the total roasting time is 31 minutes. During this, you also have to keep turning the drum continuously (60 revolutions per minute); if you stop or slow down, it easily scorches... it can be said to be quite hard on the hands.

This is the same type of coffee beans roasted by Front Street Coffee's barista at home using a drum.

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

This process is very therapeutic, and it also makes you understand that to roast coffee beans well, you need to have some knowledge of the beans themselves and learn how the roasting process development affects the flavor of the coffee beans, thereby cherishing every cup of coffee even more.

If the coffee beans sold on the market are simply categorized, basically sour ones are light roasts, bitter ones are dark roasts, and those with both sour and bitter are medium roasts. According to the color reference card provided by SCAA, the world's most authoritative specialty coffee association, coffee roast levels are divided into 8 types:

The lightestAgtronhas a color value of95, and the roast level is called Light Roast (Light Roast). The discharge time is around when first crack is密集 (the beans are still crackling as they come out), and the coffee's flavor generally shows bright acidity.

The left is medium-light roast, the right is medium-dark roast.

Agtronhas a color value of85, belonging to Cinnamon Roast (Cinnamon Roast). The discharge time is around the end of first crack (when the cracking sound has just stopped, or only sporadic cracks remain). Generally, coffee beans at this level exhibit mainly acidic notes with a sweet feel.

Agtronhas a color value of75, called Medium Roast (Medium Roast). The discharge time is approximately after first crack ends (when the cracking sound completely stops). Coffee at this level has a flavor dominated by sweetness with a slight fruity acidity.

Agtronhas a color value of65, called Dark Roast (High Roast). The discharge time is around after first crack ends and before second crack begins (about a 1-2 minute silent period). The flavor shows nutty and caramel notes, balanced, with no sourness.

Agtronhas a color value of55, called City Roast (City Roast). The discharge time is around when second crack begins (after a period of silence, one or two faint cracking sounds appear). At this point, the flavor is more bitter, with a heavier caramel aroma.

Agtronhas a color value of45, called Full City Roast (Full City Roast). The discharge time is around before second crack密集 (before you hear the crackling sound). At this point, the coffee is already quite dark, with a more burnt-bitter, rich aroma.

Agtronhas a color value of35, called French Roast (French Roast). The discharge time is around when second crack is密集 (when you hear the crackling again, though deeper than the first). At this point, the coffee beans have started to release oil.

Agtronhas a color value of25, called Italian Roast (Itatian Roast). The discharge time is around when second crack ends (after the密集 sounds). At this point, the coffee beans are pitch black and shiny, with oil already seeping out onto the bean surface.

According to Front Street Coffee's observations, whether machine-roasted or home-roasted, coffee beans are usually not roasted to a color value beyond 65, because at such deep roast levels, the coffee's flavor is already very rich and intense, without much flavor layering.

Without a certain understanding of drum roasting, it is not recommended to roast too light, because it is easy to fail to control the heat properly, resulting in the coffee bean surface reaching the color you want while the inside is not fully roasted, and the coffee may easily have a grassy/green and astringent taste~

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