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coffee beans, coffee blends, roasting, techniques - | Written by Lewis Spencer

Expert Roasting for the Best Coffee Beans

The key to enjoying the best coffees is to prepare your drinks by grinding the beans at home, using beans that have been roasted as recently as possible. The sooner you use your roasted beans, the better your coffee will taste. At Coffee-Direct we make sure that all our beans are roasted to order and quickly packaged for a fast delivery, allowing you to enjoy the fullest flavours and richest aromas in your favourite coffees.

When roasting coffee, there are a number of rules and recommendations to follow if you want to get the best flavours, aromas and colours from your beans.

You'll want to be sure that the roasting drum has been brought up to working temperature before you introduce the raw coffee. A good temperature to aim for is around 180°C; at this temperature the coffee will begin to roast straight away after being introduced to the drum, but has less chance of scorching. If the drum is too cold when you add the coffee then it will take too long to roast, which often results in a baked taste that should be avoided. If the drum is too hot then the outside of the beans will be scorched and won't cook evenly, leading to inferior flavours.

In order for the flavour within the coffee beans to be released, they have to be roasted to at least the 'first crack'. The first crack is the temperature threshold, normally around 200°C, that marks the beginning of light roasts in beans. The cracking and fracturing of the beans releases flavours and aromas, so if the coffee is roasted too lightly then the chemical reaction required to create these flavours will not have had enough time to take place. It's in this way that coffee roasting can be compared to microwave cooking; while the food may be "cooked" in a microwave, the true flavours haven't had time to be produced, just as beans that are roasted too quickly do not allow enough time for flavours to develop correctly.

The 'first crack' also acts as a useful measuring tool for determining how long to continue roasting the beans; once you've heard the cracking sound you'll be able to gauge how far into the roast the beans are, and for how long they'll need to remain roasting. After the first crack the beans will undergo increased pressure, which will continue up to the second 'crack'; darker roasts are taken up to higher temperatures and pressures that cause them to crack a second time.


Getting an even roast colour when using raw coffees can be tricky if they have very different moisture contents, partly because cracking occurs once the moisture has been evaporated, and therefore an uneven roast will be produced if the beans are cracking at different times during the roast. At Coffee-Direct we always slow the roasting process down slightly when we get near to the desired colour for a specific batch, which allows us to get an even roast colour across all of the beans.

It's essential that once the desired colour has been achieved the coffee is cooled down quickly to prevent over-roasting. Roasted beans can be cooled down rapidly with forced air, a process that reduces the risk of over-roasting and can be used to get an accurate colour and uniform flavours in the beans. When roasted beans aren't cooled down soon enough they also risking being baked, rather than roasted. Coffee beans that are baked lose their brightness and become flat in flavour and acidity, leading to inferior, insipid coffee.

Knowing what colour to roast a specific coffee to can be a difficult thing to gauge. A medium roast will give you the coffee's true origin flavour, but by roasting it longer you may create a more interesting and unique taste. This can only really be determined by trial and error, which is why we always sample roast to different colours and taste the results before deciding on the final roasting specification – a method that also allows us to experiment and discover great new roasts.

There are many different flavours and body types that can be created by experimenting with roasting times and colours. Light roasts are created shortly after the first crack in the roasting process and produce lighter bodied coffees that showcase the full origin characteristics of the bean, while medium roasts produce medium bodied coffees with some roasted flavours. The various degrees of roast and colours span a wide range of roast types, from the lighter Cinnamon and American roasts, to the dark, heavily roasted Viennese and French roasts that are created after the 'second crack' in the roasting process.

At Coffee-Direct we use a traditional gas fired drum roaster to roast our coffee beans, which utilises direct heat from the furnace onto the roasting drum. The coffee roasts in this drum, which constantly rotates to ensure even cooking and uniform colour, while also ensuring that blended batches get mixed thoroughly.

It's through these rules and methods that we're able to create uniformly roasted coffee beans, which are packed full of delicious flavours and rich, complex aromas, guaranteeing perfect coffees every time.