Coffee roasting is a magical process that transforms raw, green beans into the fragrant, brown beans we all love. In this article, we go through the key stages of roasting and explain how light, medium, and dark roasts affect the flavor.
Raw coffee beans are green, hard, and almost odorless – they smell more like grass than coffee. They contain 10–12% water and lack the complex aromas we associate with a good cup.
Roasting takes place at 180–250 °C and typically lasts 10–20 minutes. The process can be divided into these key phases:
The beans heat up, and the water evaporates. The color changes from green to yellowish. This phase takes 4–8 minutes and is crucial for an even roast.
This is where the chemical reactions begin, giving color and aroma. The beans turn yellow to light brown – the scent starts to resemble toasted bread.
An audible “pop” like popcorn. The beans expand, and most of the flavor compounds develop. This marks the end of a light roast.
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 marks the beginning of dark roasting. Going further risks burnt and bitter notes.
The beans are cooled quickly after roasting to stop the process.
Light roast (after first crack, 180–205 °C) Light brown color, no oil. High acidity, fruity and floral notes. Best preserves the bean's original character. Ideal for filter coffee and pour-over.
Medium roast (after first crack, 210–225 °C) Medium brown color, slight oil. Balanced flavor with sweetness, caramel, and nuts, along with some acidity. The most versatile roast – suitable for most brewing methods.
Dark roast (after second crack, 225–240 °C+) Dark brown to black, oily surface. Low acidity, full body, smoky and chocolatey notes. Original flavors are overshadowed. Classic for espresso and milk-based drinks.
When you roast your own beans, you gain full control over the flavor. You decide how much acidity, sweetness, and roast notes you want – and you always get the freshest coffee.
At BloomVik, we have all the equipment to get started – from compact Santoker roasters to professional solutions. It’s easier than you think, and the result is a whole new coffee experience.
Do you have questions about roasting or need help choosing the right roaster?
Write to us on the chat or email kontakt@bloomvik.dk – we’re happy to help you get started.
Happy roasting! ☕
