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Coffee Roasting

Coffee roasting is the process all green coffee beans go through before they can be used to make coffee.

The roasting process itself changes the colour of the green coffee beans. First they turn yellow, then brown. The longer they roast the darker they become. The strongest roasts result in black beans. At the same time, the heat causes changes in the taste and smell of the beans, and aromatic oils are released that bring out the flavour of coffee.

The Science of Coffee Roasting

Roasting is a critical part of coffee production as it develops and brings out the full flavour and aroma of the bean. Proper roasting requires the right temperature and the right length of roasting time.

In the nineteenth century, people carefully roasted their coffee at home on their stoves or over open fires. Now, with the growth of the coffee industry, coffee roasting has become the job of commercial coffee roasters who use enormous ovens to roast the coffee in vast quantities.

It can take just a minute to achieve the ideal roast. Roast the coffee beans for too long and you get a roast that is too dark and too bitter. As a result, temperatures and time are monitored closely and carefully controlled – sometimes even by computer - as even just a few seconds can dramatically change the final flavour of the coffee.

In general, a light roast gives a mild taste; a medium roast produces a well– rounded, rich flavour and aroma, and a high roast gives a strong, distinctive flavour.

Different varieties of beans require different levels of roasting. For instance, in order to preserve the original characteristics of Arabica beans, they should not be roasted too dark.


Roastiness is one of the three basic properties of coffee commonly checked by coffee tasters during coffee production. The other two are acidity and coffeeness.

Roastiness refers to the degree of roasting applied to the coffee beans. If you call a coffee ‘roasty’ you’re saying it has a bittersweet or smoky taste from being roasted. Too much roastiness tastes burnt.

Different Kinds Of Roasts

There are many names for the different kinds of roast, but they generally fall under these four broad categories:

A light roast gives a mild taste. It is often used with the best quality beans because it respects the original taste. The lightest roast is called Light Cinnamon.

A typical medium roast will have more body and less acidity than a light roast. It is also known as American Roast. A City Roast is slightly darker.

Full City Roast is strong, but not as strong as Viennese Roast which is rich brown in color and slightly oily.

High roasts are stronger and their smoky-sweet flavour can also be bitter. French Roast beans are almost black. The so-called Italian Roast is another high roast. In this roast the bean is caramelized, black and oily.

The NESCAFÉ® Roasting Process

With over seventy years of accumulated knowledge in coffee making, NESCAFÉ® has long mastered the roasting process.

Our expert NESCAFÉ® roasters use computer-guided roasting machines to ensure consistency in the quality of the roasted beans. In fact, this important process is one of the most fundamental parts in producing the flavoursome taste and rich aroma of NESCAFÉ® coffees.

During roasting, the coffee beans expand and change in colour. They turn to yellow once they absorb heat and then to brown as the beans lose their water content.

The beans turn darker as they release their oils, giving the coffee its flavour.

Once roasted, the beans are ground and brewed. Then they are turned into soluble coffee and packed into jars and sachets for millions of coffee drinkers to enjoy.

One of our darkest roasts is NESCAFÉ® Gold Blend® Black. To give it its unique profile, we blend mainly Arabicas with Robustas to give intensity and then dark roast them to achieve the deep, full-bodied strength we’re aiming for. The intense taste has rich, toasted notes that are beautifully balanced with a rounded smoothness.