What is the Ideal Roast Level for Blue Mountain Coffee: Blue Mountain No.1 Coffee Bean Roasting Curve

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FrontStreet Coffee Jamaican Blue Mountain Coffee Roasting Curve

Bean Entry Temperature: 170°C

Roasting is the source of coffee flavor. The process of applying heat to green beans is called roasting, and green beans cannot be consumed without it. After roasting, coffee beans determine 80% of the coffee's taste. The roasting process is tricky: if the heat is too strong, the outside cooks while the inside stays raw; if the heat is too weak, the inside overcooks. The key to a consistent roast inside and out is controlling the heat properly.

Heat Level

The heat level directly affects the roast degree of the beans, their flavor, and the roasting time. Greater heat produces more flavors, but not all of them are desirable. Sufficient heat lets the beans release more flavor compounds, but it also highlights undesirable flavors inherent in the beans.

Temperature Recovery Point

When beans enter the roasting drum, they immediately absorb heat, causing the drum temperature to drop sharply. Then, at a certain point, the temperature begins to rise again. This equilibrium point is the temperature recovery point.

Yellowing Point

Green beans enter the heat absorption stage. To transfer heat to the interior of the beans, water conductivity is used. If the beans have low moisture content, they reach the yellowing point more quickly; if they have high moisture content, it takes longer. Water evaporates and becomes steam, so the internal steam pressure and temperature rise. The beans begin to expand in structure, chlorophyll breaks down, and they enter the yellowing point.

We also sampled beans during the roast to observe how these changes unfold.

Throughout the entire process, we coordinate the air damper to bring the beans' flavor to its optimal state while keeping the beans clean.

Proper caramelization gives coffee more complexity and layers, a fuller body, and brings caramel aromas, chocolate, and roasted flavors. Pyrolysis reactions break down the substances that contribute plant-based flavors.

First Crack

First crack refers to the obvious, strong sounds coffee beans emit during roasting, somewhat like popcorn popping or firewood crackling. When beans absorb heat until the pressure from water evaporating inside exceeds the strength of the bean itself, the cell walls crack because they cannot withstand the pressure from the expanding core. At that moment the beans emit first crack, releasing thermal and acoustic energy.

This is how first crack happens. Different flavor compounds are released (aromatic substances such as floral and fruit notes), and browning occurs - which is why coffee beans are brown. It is also when the beans develop significantly: discharging one second earlier or later can make a real flavor difference.

Temperature Rise

The temperature difference between two time points. For example, between the 2nd and 3rd minute in the diagram there is a temperature difference. Subtracting the former temperature (108.8°C) from the latter (122.4°C) gives a value of 13.6°C.

Taking the roasting of FrontStreet Coffee Jamaican Blue Mountain Coffee as an example, it is important to understand the beans' characteristics. FrontStreet Coffee Blue Mountain consists of NO.1 beans sized 17 screen or larger, with a defect rate below 3% and moisture content around 13%. The beans have medium density and suit a steady, gradual roast.

When designing roasting curves, my personal experience is that attention should be paid to the fact that FrontStreet Coffee Blue Mountain roasts suit a lower bean drop temperature. Because the beans are less dense, the temperature rise after first crack should not be too high - a rise below 6°C is better, extending the development time.

First, when the drum temperature reaches 170°C, add the beans with the air damper set to 3. After 1 minute, adjust the heat to 140°C, keeping the air damper unchanged. Roast until 5'10", when the temperature reaches 153°C, the bean surface turns yellow, grassy aromas disappear completely, and dehydration is complete. Adjust the heat to 115°C and change the air damper to 4.

At 8'00", ugly wrinkles and black spots appear on the bean surface, and the bread aroma clearly shifts to coffee aroma. This can be defined as the prelude to first crack. At this point listen carefully for the sound of first crack. At 8'12" first crack begins. Reduce the heat to 90°C and open the air damper fully - adjusting the heat requires extreme care, and it should not drop so low that the crackling sound disappears. Drop the beans at 201.3°C.

FrontStreet Coffee Recommendation

To taste the result of a curve like this, FrontStreet Jamaica Blue Mountain No.1 is the reference bean. Grown in Jamaica's Blue Mountain range and drawn from the historic Clifton Estate, its growing and processing area averages 4,300 feet (1310.64 meters) - enough altitude, gentle afternoon cloud, ample sunlight, and mineral-rich soil that slow the ripening of the cherries and build the coffee's even balance.

FrontStreet roasts it to a medium-dark level so the classic Blue Mountain character comes through fully: a very clean, complex, gentle cup with chocolate sweetness and strong body, where sweet, sour, and bitter are perfectly matched, with almost no bitterness and only a moderate, elegant acidity, plus a long fruity finish. Blue Mountain No.1 is the highest grade of Jamaican Blue Mountain, and FrontStreet ships every lot within 5 days of roasting.

For brewing, FrontStreet suggests a Kono dripper and 15 g of coffee rested 4-7 days from the roast date, a grind a little coarser than for a light roast (roughly granulated sugar), water at 87-88°C, and a 1:15 ratio. Pour in three stages: 30 g to bloom for 30 seconds, then to 120 g with a slow, vertical, small stream, then to 225 g with a slightly faster flow to avoid clogging the dripper and over-extracting.