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The Color of Coffee Roast
It's very easy to distinguish a light coffee roast from a dark one. But these are two extremes. Often, the color of the roast differs by one or two tones and you can hardly see it visually. But the taste will be different. The degree of roast (or its color) is one of the main characteristics that affect the taste of coffee. In this article, you will learn what determines the color of the roast, what it affects, and how precisely to measure it.
How coffee roast color affects taste
How coffee roast color affects taste
The darker the roast, the less acidic and the more bitter coffee is. To ensure that the taste of our coffee is always stable, we carefully select and control the color of the roast. Taste descriptors such as berries, fruits and flowers are shifting towards others. Those are descriptors from the caramelization or dry distillation group: dark chocolate, nuts, caramel and smoke.
Let’s take as examples espresso and other types of coffee. Espresso is different from other brewing methods: its extraction takes 25-30 seconds, and the drink itself is more concentrated. In alternative methods, the extraction lasts 2-4 minutes, and the drink is less concentrated. In espresso, the ratio of coffee to water is most often 1/2, and the alternative is 1/16.
For espresso and alternative brewing methods, coffee cannot be roasted in the same way. It is because acids dissolve in water first, then light components, and at the very end, heavy ones. If the coffee is roasted for an alternative and brewed in espresso, it will have an unpleasant and pungent acidity in its taste. Because of the difference in the ratio of coffee and water, this effect will significantly increase. And if you roast coffee for espresso, and prepare it with an alternative method, the coffee will be too bitter.
That’s why coffee for espresso needs to be roasted longer. Especially during the second half of the roasting process (from 175 °C to 200 °C), so it will be darker and less acidic.
Let’s take as examples espresso and other types of coffee. Espresso is different from other brewing methods: its extraction takes 25-30 seconds, and the drink itself is more concentrated. In alternative methods, the extraction lasts 2-4 minutes, and the drink is less concentrated. In espresso, the ratio of coffee to water is most often 1/2, and the alternative is 1/16.
For espresso and alternative brewing methods, coffee cannot be roasted in the same way. It is because acids dissolve in water first, then light components, and at the very end, heavy ones. If the coffee is roasted for an alternative and brewed in espresso, it will have an unpleasant and pungent acidity in its taste. Because of the difference in the ratio of coffee and water, this effect will significantly increase. And if you roast coffee for espresso, and prepare it with an alternative method, the coffee will be too bitter.
That’s why coffee for espresso needs to be roasted longer. Especially during the second half of the roasting process (from 175 °C to 200 °C), so it will be darker and less acidic.
How is roast color controlled
How is roast color controlled
To be sure that the coffee roast is right, the color of the coffee is measured with laser colorimeters after each roast. They allow you to determine the color of coffee according to the ColorTrack scale.
This is how it happens: after each coffee roast, the color of beans and ground coffee is measured. And then roasters write down the values to compare them with the results of the next roasts. To do this, they use professional colorimeters, which control coffee roasting.
This is how it happens: after each coffee roast, the color of beans and ground coffee is measured. And then roasters write down the values to compare them with the results of the next roasts. To do this, they use professional colorimeters, which control coffee roasting.
To exclude the influence of ambient light, coffee is put into special cells which slide under the colorimeter laser
The higher the colorimeter value, the darker the coffee is roasted. Colorimeter for ground coffee typically values from 45 to 70 on the ColorTrack scale.
The correct degree of roast is always a very fine line. This is the line between fully revealing coffee and not getting the negative aspects of roasting: ash shades and viscosity. And this line is very easy to miss, because in the final stage of roasting every second counts and matters. That is why it is extremely important to carefully determine its color.
The correct degree of roast is always a very fine line. This is the line between fully revealing coffee and not getting the negative aspects of roasting: ash shades and viscosity. And this line is very easy to miss, because in the final stage of roasting every second counts and matters. That is why it is extremely important to carefully determine its color.
Track Roast Development Alongside Colour
What development time records
Roast logs commonly mark the development phase from the start of first crack to the end of the roast. First crack is an audible stage in the roasting process; record how you identify its start so you can compare batches consistently.
Development time ratio expresses that interval as a share of the whole roast. For example, first crack at eight minutes and a roast ending at ten minutes gives two minutes of development, or 20% of the total time. This is a calculation example, not a target for every coffee.
Barista Hustle’s guide to roast phases explains why the whole roast curve contributes to development. Keep the first-crack marker, end time, temperature readings and finished colour together when reviewing a batch.
Use colour and taste together
Colour describes one part of the result. Compare samples using the same colour-measurement method, then taste them using a repeatable preparation. This explanation of development and colour also distinguishes the outside of a bean from its interior. A single surface-colour reading does not describe the whole roast.
For a purchased product, keep the approved sample and exact coffee reference with the roast description. Use the coffee wholesale RFQ worksheet to record what you asked the supplier to quote.
Roast logs commonly mark the development phase from the start of first crack to the end of the roast. First crack is an audible stage in the roasting process; record how you identify its start so you can compare batches consistently.
Development time ratio expresses that interval as a share of the whole roast. For example, first crack at eight minutes and a roast ending at ten minutes gives two minutes of development, or 20% of the total time. This is a calculation example, not a target for every coffee.
Barista Hustle’s guide to roast phases explains why the whole roast curve contributes to development. Keep the first-crack marker, end time, temperature readings and finished colour together when reviewing a batch.
Use colour and taste together
Colour describes one part of the result. Compare samples using the same colour-measurement method, then taste them using a repeatable preparation. This explanation of development and colour also distinguishes the outside of a bean from its interior. A single surface-colour reading does not describe the whole roast.
For a purchased product, keep the approved sample and exact coffee reference with the roast description. Use the coffee wholesale RFQ worksheet to record what you asked the supplier to quote.