Coffee roasting is a magical process that transforms raw, green coffee beans into the brown, aromatic beans we know and love. In this article, we dive into the key stages of the roasting process and the different roast levels – light, medium, and dark – and how they affect the flavor.
Before roasting, the coffee beans are green, hard, and almost odorless – they smell more like grass or vegetables than coffee. They contain about 10-12% water and have none of the complex aromas we associate with brewed coffee.
Roasting typically takes place at temperatures from 180-250°C and lasts 10-20 minutes depending on the desired result. The process can be divided into these key phases:
The beans heat up, and the water evaporates. The color changes from green to yellowish/whitish. This phase often takes 4-8 minutes and is crucial for an even roast.
This is where the chemical reactions (Maillard reaction) begin, producing brown colors and aromas like bread or toast. The beans turn yellow to light brown.
An audible "pop" like popcorn! The pressure inside the bean causes it to expand – the size almost doubles. This is where most of the flavors develop. This often marks the end of light roasting.
After the first crack, the flavor continues to develop. The longer this phase lasts, the darker and more caramelized the coffee becomes.
A finer crackling – oils seep to the surface. This is the beginning of dark roasting. If you continue, you risk burnt notes.
After roasting, the beans are quickly cooled to stop the process.
The roast level is determined by how long the beans are exposed to heat after the first crack. The darker the roast, the more the coffee loses its original acidity, and roasting notes (caramel, chocolate, smoke) dominate.
Light roast
Stopped just after the first crack (approx. 180-205°C). Light brown color, no oil on the surface. Taste: High acidity, fruity and floral notes (citrus, berries). Best preserves the bean's original character. Best for: Filter coffee, pour-over – highlights nuances.
Medium roast
Developed further after the first crack (approx. 210-225°C). Medium brown color, little or no oil. Taste: Balanced – sweetness (caramel, nuts, chocolate) with still acidity and fruit. Best for: Most brewing methods, including espresso.
Dark roast
Into or after the second crack (approx. 225-240°C+). Dark brown to black, oily surface. Taste: Low acidity, bitterness, smoky and chocolatey notes (toast, smoke). Original flavors are overshadowed. Best for: Espresso, milk-based drinks.
At homeroast.dk you will find all the equipment for roasting with advanced roasters from Santoker. By roasting yourself, you can experiment with temperatures/curves and achieve fresher, more personalized coffee. Try it – it’s easier than you think!
Do you have questions about roasting? Write to us on chat or contact us at kontakt@homeroast.dk. Happy roasting! ☕
