How Are Coffee Beans Roasted?

How Are Coffee Beans Roasted?

You’re sitting in your favorite coffee shop, sipping on your favorite select roast. Maybe your working on an assignment or maybe you’re enjoying some “me-time” and reading a book. One thing’s for certain– the aroma of your coffee is lingering in the air and it's making this moment just that much better. Because of the shop’s industrial coffee roasters, the aroma is strong and lasts a while, making ordering another cup tempting. This might make you think, how are coffee beans roasted? How do industrial coffee roasters make a brew so much different than drip coffee at home? Here we’ll explain how to roast coffee beans, and even how different coffee roast temperatures create different roasts of coffee. 

industrial coffee roasting

Industrial Coffee Roasters

Even though brewing drip coffee at home is quick and convenient, the taste and texture of cafe-roasted and -brewed coffee is unmatched, owing in large part to industrial coffee roasters. Coffee from freshly roasted beans in cafes is more favorable and definitely fresher than pre-ground commercial coffee. But how are industrial coffee roasters key in a memorable roast?

How It Works

Industrial coffee roasters take the raw coffee beans that are still green from harvest and then roast them under high temperatures and pressures to make select roasts. Industrial coffee roasters can roast a large number of coffee beans, which makes them ideal for high-volume cafes. The “drum” is the part of the roaster that holds the coffee beans, and needs to be preheated before roasting the coffee beans. Once the drum is preheated, the beans can be placed in for roasting. The point of coffee roasters is to dry, or roast, the raw green coffee bean to what we usually think of as coffee beans, which are the aromatic beans ready to be ground. But how are coffee beans roasted? We’ll go into that next!

coffee roasting process

How to Roast Coffee Beans

Coffee roasters pressurize and heat the coffee beans to make them ready to be grounded. The coffee roast temperature also determines what kind of roast the beans will be destined for: light, medium, medium-dark, or dark. The process of how to roast coffee is delicate, as over-pressurizing the coffee beans can make them crumble, and roasting them at too high a temperature can burn them. Learning how to roast coffee takes great attention to detail, especially when a target roast is in mind. Roasting the coffee beans for too short may leave them still raw, and leaving them at high temperatures for too long will sap the flavor and aroma. 

In the modern world, the typical coffee roaster will rotate the coffee beans in a cylinder over hot air to evenly roast all the beans. However, in the past, coffee beans were roasted over burning charcoal, among other methods. You can imagine that today’s coffee tastes a whole lot better! After the coffee beans are roasted, they are cooled very fast to stop further roasting. A rotating cylinder over hot air and under pressure, and cooling after roasting are the main components of how coffee beans are roasted. Next, let’s explore how different temperatures result in different types of roasts, each with its own flavor profile, acidity level, and caffeine content!

grades of coffee

Coffee Roast Temperatures and Different Roasts

Temperature is everything when learning how to roast coffee beans! There are four types of roasts, and they include light, medium, medium-dark, and dark. To achieve one of them, you have to bring the coffee beans to a specific range of coffee roast temperatures for your target blend. Let’s go through how each temperature creates a specific blend. 

Light Roasts

As the name suggests, light-roasted coffee beans are roasted for the shortest time and at the lowest temperature compared to the others. For this roast, the coffee beans are heated to about 356 to 401°F until the first “crack” is heard. A coffee bean cracking means that it’s starting to dry out under the heat. The coffee bean expands due to moisture evaporation and this pressure cracks the coffee beans open. Roasting over time causes the coffee beans to lose their caffeine and acidity. Because light roasts are roasted for the shortest time, they have a higher caffeine content and acidity. Light roasts are light in the body and have notes of lemon or citrus.

Medium Roasts

You can guess that medium roasts are roasted for a little bit longer, until the temperature reaches about 410 to 428°F. Here, the coffee beans are roasted until well after the first crack, but just before the second crack is heard. Medium roasts have less acidity and less caffeine than light roasts, and are the most common type of coffee served in America. The taste profile of medium roasts is well-balanced, which is why they make up the average cup of joe!

Medium-Dark Roasts

Next, we have medium-dark roasts. These coffee beans are roasted at temperatures of about 437 to 446°F to reach their second crack. Medium-dark roasts are fuller than the last two, less acidic, and have less caffeine. 

Dark Roasts

Finally, coffee beans destined to become dark roasts are roasted at temperatures between 464 to 482°F. Dark roasts have the least amount of caffeine, are the least acidic, and have more flavor than the other roasts. Dark roasts are often sweeter because the natural sugars inside the coffee beans caramelize at these higher temperatures. This type of roast is also more popular in Europe, such as with the French roast. The French roast is widely considered the darkest roast available, and it has a smoky flavor because the beans are roasted at the highest temperatures possible before they completely burn.

There’s a lot of care and precision involved in how coffee beans are roasted, so the right roast is reached! From pressurizing to gauging the right temperatures for roasting coffee beans, it’s not a simple process, which will make your next cup of coffee that much more special. Coffee roasted and ground in-shop goes above and beyond in taste, texture, and body compared to superstore blends because of the care taken. Industrial roasters help make cafe blends exceptional, as well as the talent and wealth of knowledge that goes into creating decadent blends!

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