Whether dark, light or medium, roast profiles have a significant impact on the flavour and characteristics of your coffee. Defined, simply, as a set of parameters used to determine the way in which a coffee is roasted, roast profiles are largely dependent on your control of the roasting machine, as well as the data you capture from it.
However, to achieve a desired roast profile, roasters must also take into account a number of different factors concerning the coffee itself, from density and processing to variety and hardness.
To find out more about roast profiles, and how an understanding of them can benefit specialty coffee roasters, I spoke with Rafael Silva from Entre Cerros Coffee Roasters in El Salvador.
What Is A Roast Profile?
A roast profile is a set of parameters that define how a coffee should be, or has been, roasted.
Most roasters are fitted with a probe to measure the temperature of the beans in the drum, a probe to measure the exhaust gas, and an adjustable heat input. Specialty coffee roasters can use these three data points, along with time, to build a reliable roast profile.
Roast profile logging software, such as Cropster, is used to capture the data and display it on a graph in real time, which allows roasters to make necessary adjustments.
According to coffee roasting expert Scott Rao, a typical roast profile generally follows an “S” curve in which bean temperature drops for 70 to 90 seconds, bottoms out, and then rapidly increases.
Before starting the roast, it’s important to work out a starting point for your roast profile by analysing various aspects of the beans. Factors such as bean density, hardness, moisture content, screen size, and batch weight can all have a profound influence on the final roast profile.
Rafael Silva works for Entre Cerros Coffee Roasters in El Salvador. He tells me that knowing this information will help roasters understand how their coffee will develop during the roast, how much heat and airflow will be needed to control the roast, and what the initial temperature, or charge temperature, should be before the beans are dropped into the drum.
“It’s vital we know the density of the beans before roasting,” Rafael explains. “Coffees with a low density and hardness will need a lower initial charge temperature, as they can easily become overroasted.
“Higher density coffees need a higher initial temperature to dry out the coffee faster and experience better development.”
He also says that variety plays a crucial role in how the coffee is roasted.
“All varieties are of different densities, no matter the altitude and location of the farm,” he says. “Some varieties are rounded shapes which makes them easier to roast, while others are elongated or pointed. These are extremely difficult to roast as we need to be careful not to burn the tips of the beans.”
As well as density and variety, processing methods can have a significant effect on the roast profile.
Natural (dry) processed coffees and carbonic maceration methods both leave a lot of residual sugar in the beans, which, if not treated accordingly, can easily take on too much heat and burn the coffee.
Measuring Roast Profiles
Before the appearance of roasting software, roasters would have to rely on certain physical changes within a bean to determine how much heat was needed for their coffee to reach full development.
However, technological advancements mean that roasters are now able to put together exact timings and temperature points along with a bean’s physical markers.
Depending on the style of a roast, you will want these physical markers to happen at different times to either eliminate or highlight certain flavours from the bean.
Daily Coffee News states that a good place to start with profile translation analysis is to examine ranges that are marked by easily observable physical changes.
Examples of ranges include the start of the roast through to the start of the colour change from green to yellow and yellow to brown, and from the start of first crack (when the temperature reaches around 196°C) to either the end of the roast or to the start of second crack.
Other important, measurable elements that make up a roast profile are the turning point, rate of rise, and end roast weight loss.
Using roast profile logging software, roasters can track and measure results within these ranges and markers, and make changes accordingly. Essentially, the more data you can capture during the roasting process, the more accurate and consistent your roast profile will be.
The physical changes that happen inside a bean during the roast are complex, and understanding what’s happening at different stages can require a lot of trial and error. However, knowing at what temperature certain chemical reactions happen and how they affect the outcome of a roast is crucial when refining a roast profile.
Using Roast Profiles To Develop Flavour
Through small adjustments made during the roasting process, each roaster can craft their own distinct flavour of coffee.
Whether it’s body, acidity or sweetness, they must decide which characteristics they want to highlight, and which they want to hide. However, with more than 300 flavour components in every green bean, achieving a desired profile is a complex process that requires lots of testing and dialling in.
“You can roast to enhance acidity, to improve sweetness, to hide bad flavours, or just go as dark as you like,” Rafael explains.
Rafael says that when sampling coffees, he goes in search of specific characteristics that he knows will appeal to his customer base. However, he warns that even if using the same batch of coffee, it’s important to constantly assess the outcome of the roasts to ensure the best results.
“You need to be carefully watching over your roasts each time because coffee is constantly changing. It can gain or lose humidity, it can start fading off or degrading.
“I would advise cupping your roasts all the time to see how the coffees are developing over time, and whether you need to make any adjustments.”
Roast profiles can take a while to get right; but with reliable software and a firm understanding of the various factors at play during roasting, you should be able to develop an initial roast profile quickly, providing you with a good base from which to refine how you roast a coffee over time.
At MTPak Coffee, we offer a range of sustainable packaging options that can reflect the distinct roast profiles, flavours, and characteristics of a broad variety of specialty coffees.
You can choose from a variety of features, from degassing valves to resealable zippers, to ensure that once you have achieved your desired roast profile, you can preserve the freshness of your coffee right up until it arrives at the consumer.
To discuss packaging options for specialty coffee, contact our team.
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