Types of coffee roasts: What are the differences?

Different types of roasts bring out different characteristics of the beans. Whether you're a casual coffee drinker or a budding barista, understanding these nuances of coffee roasts will help you appreciate every cup even more.

Before the magic happens, one of the most important things after harvesting any type of coffee bean, is to keep them fresh and green for as long as possible. This locks in the quality and freshness. When it’s roasting time, the heat hardens the beans and ramps up their flavour as they darken. There are plenty of ways coffee beans can be roasted. In trendy specialty roasteries filled with burlap sacks and baristas, skilled roasters tend to use cast iron pans. But larger batches are usually roasted in industrial-sized roasters, although still carefully monitored for quality.

How coffee beans are roasted: the 5 steps

When coffee roasters describe the process, they focus on five steps:

1. Drying or yellowing - This first phase is where the roaster looks at the moisture level of the beans to decide the length and temperature of the roasting. The beans go yellow as they lose moisture.

2. Maillard reaction - Now the coffee bean starts to change into the brown colour we prize so much, as sugars break down and caramelise in the heat and the beans develop that familiar coffee flavour.

3. First crack - The first crack happens when the bean expands and releases steam, much like the pop of popcorn.

4. Second crack - Some roasts are removed after the first crack, but for darker roasts, they're pushed a bit further to a second crack. And now it’s all about getting the delicate balance just right.

5. Carbonisation - This final phase is always a risky one. Some might like to get really close to it for a very dark roast, but when the beans get carbonised they sometimes catch on fire and get burnt to a unpleasant crisp — an obvious no-no.

Why does it matter how coffee is roasted?

The temperature at which the coffee beans are roasted, and how much time they're roasted for, has a big effect on how the coffee will end up tasting in your cup. Think of what happens when you add sugar to a heated pan. With the right amount of heat and timing, that sugar turns into a yummy brown caramel. Leave it on the stove for too long, or at too high a temperature, and you’re left with a blackened crust you'll get a workout cleaning later on.

Coffee beans contain both water and sugar. As soon as the water evaporates during roasting, the sugar is very vulnerable to the heat. There’s a fine balance to strike at this point: between that pleasant hint of bitterness in a dark roast, and making it so harsh it’s undrinkable. A touch of caramel is great, but overly fruity and sweet coffee isn’t ideal either. Mastering that balance is key to crafting the perfect cup.

What does “strong coffee” really mean?

There’s a common myth that darker coffee is stronger coffee. Wrong! It's actually quite the opposite. Although darker roasts are more aromatic and might have more punch in the flavour department, the heating process lowers the amount of caffeine present and active. So if you're the type of coffee drinker simply looking for the kick early in the morning, try out a lighter roast next time. You might just be surprised.

The different coffee roast types

Coffee roasters are true artists, carefully tweaking the temperature and roasting time to get the roast they're aiming for. They have a few tricks of the trade up their sleeves to tell when their coffee roasts have arrived at their checkpoint:

Light roast coffee

Depending on where you are in the world, light roast can also be labelled Cinnamon, Light City, or New England Roast. It has a lighter body and is excellent for highlighting the flavours of single-origin beans.

Medium roast coffee

Again, the name for it differs from country to country as it can also be called a City, Half City, or Full City Roast. It has a fuller bodied flavour, thanks to a slightly longer roast.

Medium-dark roast coffee

Also known as High Roast or Continental Roast, these coffee beans have a little more depth and robustness to the flavour.

Dark roast coffee

Other names for this roast include Viennese, Italian and French Roast and these beans develop a deep, smoky flavour and colour.

What’s the perfect roast for espresso?

If you think of espresso, you might be forgiven for thinking it must be a special type of dark roast, but espresso is the result of the fast, high-pressure brewing method, not the roast type. Any type of coffee roast can be used to make an espresso, but preferably one that’s not too oily. The oil tends to build up in your espresso maker over time to leave you with terrible tasting coffee. So when picking out coffee for your home espresso machine, sticking with the lighter roasts is a good call.

Time to get grinding

After you’ve chosen the different types of coffee roasts that suit your tastes, there is one final step before you get to making that perfect cup. Grinding coffee beans is where many coffee lovers trip up when making coffee at home. The grind size really matters: a finer grind means the water passes through more slowly, while a coarser (bigger) grind lets it flow more quickly. This affects the extraction process and, ultimately, the taste of your coffee. Different brewing methods require different grind sizes — think coarse for French press, medium for drip coffee, and fine for espresso. A home espresso machine with an integrated grinder will make sure you get the grind exactly right, and fine enough for your espresso drink to have an exceptional taste.

TIP: Too bitter? over-extracted – try a coarser grind

Too watery? under-extracted – try a finer grind.