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What is Coffee Roast Profile
This article will help you understand what a coffee roast profile is and why you need to select special coffee roast profile for each coffee variety.
The degree of roast is generally its color. But even with the same color of roast, coffee may taste completely different. The main reason for this – different coffee roast profiles which are much more complex part of the roasting process.
Generally, it is a kind of "recipe" according to which coffee is roasted, but roaster controls processes instead of ingredients. This article will help you understand in details what a coffee roast profile is and why you need to select special coffee roast profile for each coffee variety.
Generally, it is a kind of "recipe" according to which coffee is roasted, but roaster controls processes instead of ingredients. This article will help you understand in details what a coffee roast profile is and why you need to select special coffee roast profile for each coffee variety.
How coffee roasting works
During the roasting process, there are numerous chemical reactions that take place in it. Resulted complex volatile compounds form the flavor and aroma of coffee. Different compounds are formed at different temperatures and roasting stages. So, by controlling these stages, roaster can adjust the taste of coffee.
Roasters must see what is happening with the coffee beans, so they use two temperature sensors, each of which displays two curves on the screen: temperature and its rate of change. One of the sensors is installed so that it reads the temperature of the beans, and the second records only the temperature of the air that goes out of the drum.
This allows roasters to control the whole process with high accuracy. They can influence roasting by the amount of energy applied to the beans, by the speed of the air flow that removes heat from the drum, etc.
Roasters must see what is happening with the coffee beans, so they use two temperature sensors, each of which displays two curves on the screen: temperature and its rate of change. One of the sensors is installed so that it reads the temperature of the beans, and the second records only the temperature of the air that goes out of the drum.
This allows roasters to control the whole process with high accuracy. They can influence roasting by the amount of energy applied to the beans, by the speed of the air flow that removes heat from the drum, etc.
The roasting itself has several stages:
• Drying (up to 130 °C),
• Maillard reaction (from 130 °C),
• Caramelization (from 170 °C),
• Development time (from the moment of "crack" to the end of the roast).
Together, these steps add up to a total roasting time of 8 to 14 minutes. Inexpensive commercial varieties often roast longer, but good coffee isn’t usually roasted longer than 14 minutes.
• Drying (up to 130 °C),
• Maillard reaction (from 130 °C),
• Caramelization (from 170 °C),
• Development time (from the moment of "crack" to the end of the roast).
Together, these steps add up to a total roasting time of 8 to 14 minutes. Inexpensive commercial varieties often roast longer, but good coffee isn’t usually roasted longer than 14 minutes.
What is coffee taste made of?
Coffee taste is always a compromise between two parts. The first part (“enzymatic”) is what the bean got by genetics, processing, etc. It includes berry, fruit, flower and other descriptors. The second part belongs to the group of “caramelization of sugars” (formed from the moment of “crack” until the end of roasting). These are notes of chocolate, caramel, etc. It turns out that roasters can regulate in which direction to drag the taste more - into the “enzymatic” part or into “caramelization”.
What is the "development time" of coffee
During roasting, evaporating moisture and carbon dioxide, formed from ongoing reactions, try to get out of the bean, but partially rest against the cell walls. The pressure is increasing, and as a result, the bean cracks with a jerky sound. This moment is a "crack".
It is extremely important to fix its beginning on the chart. The time from the "crack" to the discharge of coffee is called the development time. In order for the coffee flavor to develop, the development time should be from 15% of the total roast time for a filter and from 20% for espresso.
There are two cracks during roasting process. The first one occurs at temperatures up to 200 °C, mainly due to evaporating moisture, the second one usually occurs after 220 °C, due to the burning of sugars and cell walls. Coffee roasted to the second crack is very dark with oil coming out on the surface.
It is extremely important to fix its beginning on the chart. The time from the "crack" to the discharge of coffee is called the development time. In order for the coffee flavor to develop, the development time should be from 15% of the total roast time for a filter and from 20% for espresso.
There are two cracks during roasting process. The first one occurs at temperatures up to 200 °C, mainly due to evaporating moisture, the second one usually occurs after 220 °C, due to the burning of sugars and cell walls. Coffee roasted to the second crack is very dark with oil coming out on the surface.
Use Heat and Airflow as Part of the Roast Profile
Read what each curve measures
A roast profile records how a batch progresses over time. Before comparing graphs, identify each temperature sensor and the machine, batch size and coffee used. A bean-temperature curve, an exhaust-temperature reading and a burner setting describe different things.
The Loring Roast Architect manual distinguishes temperature-based roast profiles from burner recipes in that system. Use the documentation for your own roaster when interpreting its curves and controls.
Record heat and airflow changes
Airflow moves hot air through the system and removes smoke and chaff. Its effect depends on the roaster and the heat settings used. Barista Hustle’s airflow lesson explains that raising airflow can change both heat transfer and heat loss. Record the adjustment and the resulting curve rather than assuming one fan setting will have the same effect on another machine.
Compare the finished result
Keep the coffee lot, roast log, colour measurement and tasting notes together. Use a repeatable brewing method when comparing batches, then change one part of the trial and record the next result.
For a finished coffee order, keep the approved sample reference with the roast description and quotation. The coffee wholesale RFQ worksheet helps collect the exact product, pack and order request.
A roast profile records how a batch progresses over time. Before comparing graphs, identify each temperature sensor and the machine, batch size and coffee used. A bean-temperature curve, an exhaust-temperature reading and a burner setting describe different things.
The Loring Roast Architect manual distinguishes temperature-based roast profiles from burner recipes in that system. Use the documentation for your own roaster when interpreting its curves and controls.
Record heat and airflow changes
Airflow moves hot air through the system and removes smoke and chaff. Its effect depends on the roaster and the heat settings used. Barista Hustle’s airflow lesson explains that raising airflow can change both heat transfer and heat loss. Record the adjustment and the resulting curve rather than assuming one fan setting will have the same effect on another machine.
Compare the finished result
Keep the coffee lot, roast log, colour measurement and tasting notes together. Use a repeatable brewing method when comparing batches, then change one part of the trial and record the next result.
For a finished coffee order, keep the approved sample reference with the roast description and quotation. The coffee wholesale RFQ worksheet helps collect the exact product, pack and order request.
27.08.2021