How Do You Design a Roast Curve for Yirgacheffe Beans?

Yirgacheffe beans carry floral and fruity notes that depend heavily on how the roast is built. The work starts with the green coffee's own character, then sets charge temperature, heat adjustments, and first crack timing around it. Rather than chasing one exact drop minute, the approach tests a hypothesis, samples at set points after first crack, and cups the results to confirm which interval fits the intended flavor.

In a documented case, samples of 11g were pulled 30, 50, and 60 seconds after first crack began, then at 25%, 50%, and 75% of the gap between first and second crack, and again as second crack started. Cupping those samples shows which part of the roasting process reliable matches expectations for a light, slow roast, and the same method transfers to other lots.

Yirgacheffe is renowned for its spectacular floral and fruity flavors, but to fully unlock this bean's potential, the design of the roasting curve is crucial. Starting from Front Street Yirgacheffe's actual roasting case, this article systematically sorts out the core logic of roast curve design—how to determine the optimal drop time through hypothesis, sampling, and cupping, and analyzes the key operational points of a light, slow roast in combination with green bean characteristics. The article also records in detail the complete roasting process from charge temperature and heat adjustment to first crack timing, as well as the parameter corrections and flavor comparisons across two rounds of V60 brewing, providing coffee enthusiasts with a Yirgacheffe roasting and brewing guide that combines theoretical basis with practical reference.

How is the roasting curve of Front Street Yirgacheffe coffee beans designed?

How do you confirm the optimal time point for roasted coffee beans?

This question is actually asking how to design a coffee bean roasting curve

In fact, the optimal time point is not the basis for making a final judgment either. It is not that dropping the beans at a precise minute and second can prove that the roast level or quality has reached a unified standard. This also involves many variables such as the characteristics of the green coffee beans themselves and the trend of the rate of rise throughout the roasting process. So for this question, if we simplify it to the greatest extent, setting aside other factors for now and discussing only how to judge the single roasting variable of drop time, you can operate as follows (this is a simplified version, on the premise that you already have a grasp of the green bean characteristics, the turning point is within the normal range, and conditions such as heat have already been fixed):

Step 1 Make a hypothesis

Based on your daily roasting experience, first make a rough prediction. For example, generally speaking, approximately:

At what time point does first crack begin?

How long will first crack last?

How long is the interval between first crack and second crack?

Step 2 Sampling

30 seconds, 50 seconds, and 60 seconds after first crack starts, at 25%/50%/75% of the interval from first crack to second crack, before second crack arrives, when second crack starts, and upon entering second crack

Take an 11g sample at each node

Step 3 Cupping

Cup the samples taken to determine which interval range best meets your expectations.

Then you can make a judgment!

Note: In actual operation, you may need to try repeatedly many times, pay attention to a large number of details, and possess rigorous recording habits and a spirit of exploration to truly achieve results.

Yirgacheffe itself is a local heirloom variety, small bean variety, relatively round in appearance, very small in bean size, mostly between 14-15 screen size

Yirgacheffe Cherry Red Grade 1 green beans are yellow-green in color, the typical color of natural-process coffee, with uniform and plump beans and few defective beans

04 | Roasting Analysis

A bean with such spectacular flavors is of course not suitable for a medium-dark roast, so this coffee is planned to use a light slow roast method, which best reflects its rounded and sweet characteristics with rich floral and fruity aromas.

This coffee's beans are relatively small, and its moisture content means it also absorbs a relatively large amount of heat during roasting, and the Maillard reaction process is also relatively fast.

In the first roast, I used a relatively high drop temperature and used 160 heat before the coffee beans dehydrated and turned yellow, to ensure there was enough heat to continue until first crack and develop directly to second crack, confirming the curve development

In the second, third, and fourth roasts, the same charge temperature of 200 and the same heat were used, and during the roasting process the heat was gradually reduced as needed.

This batch was a fast-roasted light roast:

Cupping:

Roast one: strawberry , raspberry, vanilla, honeydew, juicy

Roast curve 2: strawberry, raspberry, vanilla, honey, fruit juice

Roast two: manguo, black brin , , citrus juicy

Roast curve 3: mango, black plum, blueberry, citrus juice

Roast three : citrus juicy , cream

Roast curve 3: citrus juice, cream

Roaster Yangjia 600g semi-direct fire

Using fast-roast mode, charge when the roaster temperature reaches 200°C, set the damper to 3.5, adjust the heat to 160°C after 1 minute, keep the damper unchanged, adjust the heat once at 148°C, lower it to 130°C, roast until 5‘03”, at 151°C, when the bean surface turns yellow, the grassy smell completely disappears, and dehydration is complete, adjust the heat to 105°C, and open the damper to 4;

At the 8th minute, ugly wrinkles and dark spots appear on the bean surface, and the toast smell clearly turns into coffee aroma, which can be defined as the prelude to first crack. At this time, you must listen clearly for the sound of the first crack point. At 9’07”, first crack begins. Reduce the heat to 70°C, open the damper fully (adjust the heat very carefully, and do not reduce it so much that there is no crackling sound), and drop at 194°C.

The dry aroma of Front Street Yirgacheffe exudes an intense fruity fragrance, with a heavy dried-fruit note, and aromas of strawberry, mango, and apricot jam.

The wet aroma is like sweet syrup, like viscous apricot nectar wrapped in rustic honey or chocolate. On the palate it is not intense, with medium body, and the acidity is not obvious yet lively and bright, like fruity black tea.

04 | Brewing Analysis

The flavor of Front Street Yirgacheffe

Brewing method

As for the brewing method, pour-over and siphon are the best. When grinding the beans, you can already smell the striking natural-process fruity aroma, with obvious sweetness.

Gentle and elegant, sweet and lovely. Front Street Yirgacheffe exudes an extremely complex aroma and displays an extremely outstanding mouthfeel, making it difficult to describe.

First brew: V60 dripper, 15g grounds, water temperature 90°C, grind setting 4, water-to-coffee ratio close to 1:15

31g water for blooming, bloom time 29s

Stages: pour to 99ml and stop, then slowly pour to 230ml

That is, 31-99-100

Taste: strawberry acidity is obvious, with astringency in the finish and some off-flavors

Adjust grind setting from 4 to 3.5 (finer), lower the water temperature

Second brew (revised): V60 dripper, 15g grounds, water temperature 86°C, grind setting 3.5,

water-to-coffee ratio close to 1:15

27g water for blooming, bloom time 28s

Stages: 27-105-88, time 1:50 (timing starts at the beginning of blooming)

Taste: smooth, the flavor is much fuller, with layering, and the fermented berry sweetness is enhanced

The wet aroma of the finished cup, with ripe berry fermented fruit wine notes, makes it hard to believe this is Front Street Yirgacheffe, but personally I do not particularly like this wet aroma. However, from the extremely smooth entry to the delicate body, the surge of ripe fruit sweetness truly makes one feel amazed, and the sweetness exceeds that of any Yirgacheffe I have drunk before. The finish also performs quite well, truly deserving the title of “fruit bomb”; after drinking, it can basically be guaranteed that sweetness will still be felt in the mouth for half an hour.

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The above content is compiled by CoffeeHunters, a coffee news website.