Roast coffee beans - how to do it

Tommy Winberg

Roasting coffee beans is a crucial step in bringing out their unique flavors and aromas. Roasting transforms raw coffee beans into the finished product we use to brew coffee. Each roast level contributes its own character and flavor profile. This guide will take you through everything from different roast levels to how you can roast coffee at home.

Coffee flavors & aromas

When coffee beans are roasted, their natural flavors and aromas are enhanced, and the roast level has the greatest impact on the taste. Light roast coffee often offers fruity and acidic notes, while dark roast highlights deeper, earthy, and chocolatey flavors. The aromas released during roasting depend on both the bean's origin and the roasting process, with each level contributing to a unique taste experience.

Roasting coffee at home

Roasting your own coffee at home gives you control over the flavor, and you can experiment with different roast levels to create your own perfect cup. Home roasting only requires raw coffee beans, a heat source, and some time to learn how to roast the coffee beans to perfection. By roasting it yourself, you can influence everything from the acidity levels to the body and aromas in the coffee.

Roasting in the oven

If you want to try roasting coffee at home, the oven is an easy option. By roasting the coffee in the oven, you can experiment with different roast levels and learn more about how they affect the coffee's flavors.

Here's how to do it:

Start by preheating the oven to 200–230°C
Spread the beans in an even layer on a baking sheet
Roast for about 10–15 minutes, depending on the desired roast level
Stir the beans a few times for an even color
When the beans start to crack and release aromas, they are ready
Let them cool and air out before brewing for the best flavor

Popcorn machine

A popcorn machine is an unexpected but effective tool for roasting coffee beans at home. The hot air technology roasts the beans quickly and evenly, making it ideal for small quantities of coffee.

Here are the steps for roasting coffee in a popcorn machine:

Choose a hot air popcorn machine
Preheat the machine for about 30 seconds before adding the beans
Add a small amount of raw coffee, about half a cup
The beans roast in about 5–10 minutes
Listen for the "first crack" and check if the beans start to expand
Pour the beans into a colander or onto a baking sheet as soon as they are finished
Remove the chaff, the thin skin that comes off the beans during roasting

Different roast levels

The roast level affects the coffee beans' flavor, aroma, and body. Listen for the crackling during roasting to achieve the type of coffee you want, from light to dark roast. Each step provides unique flavor characteristics.

First Crack - During the first crack, the beans expand and release their natural flavors. If you prefer a lighter roast, stop shortly after this step. Light roast often provides fruity, acidic flavors and a lighter body.
Second Crack - For a deeper, fuller flavor, the beans can be roasted further to the second crack. Here, the roast becomes darker with intense chocolatey, smoky notes and less acidity. However, be careful, as high heat can quickly lead to over-roasting.

After roasting, it is best to let the beans cool completely and then store them in an airtight container. For best results, it is recommended to let the beans rest for 12–24 hours before brewing, so that the aromas can mature and provide a rounder flavor in the cup.