The Yirgacheffe Roasting Curve | Sharing the Ideal Roasting Profile for Washed Yirgacheffe

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Sharing FrontStreet Coffee's Washed Yirgacheffe Roasting Curve

The coffee being roasted is Ethiopian Yirgacheffe Red Cherry. After first crack, the beans are dropped when the temperature increases by about 10-12 degrees. The development time is controlled between 70-90 seconds, depending on the actual condition of the beans. However, unlike the washed process, the temperature rise curve after first crack has been flattened slightly to prevent it from dropping too early, ensuring a complete development period to achieve the aftertaste characteristic of natural process beans.

With a roasting approach in mind, it's time to start experimenting~ Using the same dropping temperature, I'll run both a heating curve and a cooling curve to try which roasting method is more suitable for this particular bean~~

Roasting Parameters:

Roaster: Sanheke R200
Roasting amount: 250 grams at full capacity
Drum rotation speed: 70 rpm
Indoor temperature on the day: 30°C
Humidity: 70%
Natural process Yirgacheffe Red Cherry: 250 grams, 2018 harvest season

Curve One:

The roasting method used is low heat dehydration in the early stage, with an initial damper setting of 30%. As roasting progresses, the heat gradually increases while the damper gradually opens. The damper is fully opened at the beginning of first crack.

Bean in temperature: 185°C

About Dropping Temperature

The dropping temperature primarily affects the degree of caramelization and pyrolysis reactions of sugars (mainly sucrose) in coffee. Both caramelization and pyrolysis require heat absorption to complete, so these reactions need continuous heat supply to proceed. Therefore, in coffee roasting, the degree of these reactions is directly proportional to the dropping temperature.

The higher the dropping temperature, the deeper the reaction degree. Lower dropping temperatures result in coffee with floral and fruity aromas and high sweetness because more sugars are retained without being pyrolyzed. As the dropping temperature increases, the floral and fruity aromas first develop toward maturity and then gradually decrease, while nutty, caramel, and chocolate flavors become more pronounced, increasing complexity, body, and layers.

Therefore, I usually choose a dropping temperature of 185°C for natural process beans and 190°C for washed process beans.

Yellowing point: 152°C at 4 minutes 40 seconds
First crack point: 193°C at 8 minutes 40 seconds

Originally planned to drop at 203°C. During roasting, sampling revealed a hint of citrus aroma that was fleeting, so I confirmed frequently until 204°C (when the citrus aroma was strongest) and realized I couldn't wait any longer. Quickly dropped the beans at 205°C!!

Dropping point: 205°C at 10 minutes 25 seconds

This batch of green beans: 250g → Roasted beans: 217.5g → Weight loss: 13%

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473