Coffee Roasting


We have seen previously where the coffee beans come from, how they get treated and prepared before becoming the ones that we consumed by enjoying our favorite drinks.

Today we are going to have a better look into the process that takes place after the processing of the beans and will produce the final product: the coffee beans roasting.
There are many things about the roasting process that need to be considered, you may have heard of the different methods of roasting or the different levels used to roast the beans, but do you know what are the differences between them?

The first recorded roasting of the beans comes from the Ottoman empire in the 15th century, where the beans were roasted directly in metallic pans with long handles over braziers.

Since the early 20th century, roasting became less and less popular due to the rise of commercial coffee companies, but home roasting aficionados are being more and more popular, whether for passion or for a better control over the quality of the finalised product.


Why are the beans roasted?

The roasting of the beans is necessary to bring out the aroma and the flavors that are otherwise locked inside the green coffee beans. The chemical changes provoked by the high temperatures of the roasting process allow them to penetrate the whole bean

Green beans are soft and spongy with a smell very similar to the one of the grass, and the flavor and taste that we feel in the drinks is locked inside them while they are not roasted. That is the reason why they are stored while still being green, as once roasted the beans tend to lose their flavor bit by bit.

What are the different roasts?

The industry doesn’t have a fixed standardisation for the different roasts, but all producers agree on levels going from light roast to medium and dark roast.

  • Light roasts: defined by its light brown colour, the beans present a lack of oil at their surface due to the roasting not being long and strong enough to make them break through the surface. This roast is generally preferred for milder varieties of coffee
  • Medium roasts: They have a richer aroma than the light roasts and a darker colour, with some oil present on the surface. As drinks, they can have a slightly bitter aftertaste.
  • Dark roasts: The beans will have a shiny black colour with an oily surface. The more the beans are roasted, the more the beverage will then present a pronounced bitterness and a lack of acidity.

Within those three “main categories” of roasting, there are different degrees that all bear their own denominations: French roast, City roast, Espresso, Viennese, Italian… All those have their own specific recipes that can explain how to achieve them and bring out a particular flavor thanks to several characteristics (origins, variety, processing method of the beans…)

Finally, there are several indicators for during the roasting process, but the main ones are the colour (light brown, dark brown, black…), the smell and the sound. The latter is a good indicator for the temperature, as there is the possibility to hear two “cracks”: on at approximately 195°C, the “first crack”, that is an indicator for the beginning of the light roasts. Another crack is heard at around 225°C that alerts about the collapsing of the structure, which will lead to the carbonisation of the beans.

There is so much more to know about the roasting processes and all their characteristics, but I hope that this article gives you a better understanding already!

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