Colombia Isabella (Pink Bourbon) Curve Fine-tuning Sharing!

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Pink Bourbon: A Rare Coffee Variety

Pink Bourbon was first cultivated in the Huila region. Initially, it was planted mixed with other Bourbon and Caturra varieties before being separately harvested and processed. When the coffee cherries mature, they display a romantic pink color, but maintaining this pink hue is exceptionally challenging. The final color of coffee beans is determined by recessive genes within the pollen grains. The hybridized pollen grains contain genes that trend toward both yellow Bourbon's yellow genes and red Bourbon's red genes, all of which are recessive and easily interfere with each other, making Pink Bourbon an extremely rare variety.

Flavor Characteristics

The rare Pink Bourbon also exhibits distinctive characteristics in the cup. Unlike the typically flat flavor profile of regular Bourbon varieties, Pink Bourbon possesses fresh floral aromatics, juicy sweetness reminiscent of blueberries and green grapes, cherry notes in the middle phase, and a brown sugar-like sweetness in the finish. In terms of acidity, it presents complex citrus and berry notes.

Roasting Optimization

Due to Pink Bourbon's unique flavor expression, we previously shared a detailed introduction about this bean: "FrontStreet Coffee's Bean Hunter's Journal: Rare Pink Bourbon from Colombia's La Minita Estate." To better unlock the flavor potential of this bean, FrontStreet Coffee's roaster has made fine adjustments to the previous roasting curve. Today, we'll share how this Pink Bourbon performs with the adjusted curve.

Before Curve Adjustment

Roasting Equipment: Yangjia 800N (batch size: 300g)

Preheat the roaster to 180°C, set the air damper to 3, and heat at 120 power. The turning point occurs at 1'42" with the temperature at 140°C, maintaining the same heat and opening the damper to 4. At this point, the bean surface turns yellow and grassy aromas completely disappear, entering the dehydration phase. At 176°C, reduce heat to 100, then to 70 at 180°C, keeping the damper unchanged.

At 8'17", ugly wrinkles and black spots appear on the bean surface, with toasted bread aromas clearly transitioning to coffee fragrance. This can be defined as the prelude to first crack. At this moment, listen carefully for the sound of first crack. First crack begins at 9'30", adjust the damper to 5 (be very careful when adjusting heat - don't reduce it so much that crackling stops), develop for 1'30" after first crack, and discharge at 191.5°C.

Agtron bean color value: 75.9 (above), Agtron ground color value: 82.5 (below), Roast Delta: 6.6.

Cupping Results: Citrus, floral, honey, berries, nuts, cream.

After Curve Adjustment

Curve One

Preheat the roaster to 180°C, set the air damper to 3, and heat at 100 power. The turning point occurs at 1'43" with the temperature at 140°C, maintaining the same heat and opening the damper to 4. At this point, the bean surface turns yellow and grassy aromas completely disappear, entering the dehydration phase. At 151°C, reduce heat to 80, then to 65 at 166°C, keeping the damper unchanged.

At 9'07", ugly wrinkles and black spots appear on the bean surface, with toasted bread aromas clearly transitioning to coffee fragrance. This can be defined as the prelude to first crack. At this moment, listen carefully for the sound of first crack. First crack begins at 10'55", adjust the damper to 5 (be very careful when adjusting heat - don't reduce it so much that crackling stops), develop for 1'35" after first crack, and discharge at 190.2°C.

Agtron bean color value: 79.1 (above), Agtron ground color value: 82.8 (below), Roast Delta: 3.7.

Cupping Results: Citrus, tea aromatics, honey, floral, berries, nuts.

Curve Two

Preheat the roaster to 180°C, set the air damper to 3, and heat at 100 power. The turning point occurs at 1'40" with the temperature at 140°C, maintaining the same heat and opening the damper to 4. At this point, the bean surface turns yellow and grassy aromas completely disappear, entering the dehydration phase. At 151°C, reduce heat to 80, then to 65 at 166°C, keeping the damper unchanged.

At 8'35", ugly wrinkles and black spots appear on the bean surface, with toasted bread aromas clearly transitioning to coffee fragrance. This can be defined as the prelude to first crack. At this moment, listen carefully for the sound of first crack. First crack begins at 9'58", adjust the damper to 5 (be very careful when adjusting heat - don't reduce it so much that crackling stops), develop for 1'28" after first crack, and discharge at 193°C.

Agtron bean color value: 75.1 (above), Agtron ground color value: 79.3 (below), Roast Delta: 4.2.

Cupping Results: Floral, caramel, lemon, honey, nuts, chocolate.

Curve Analysis

Both adjusted curves produce prominent floral aromatics, fruit acidity, and sweet-sour balance in cupping. Curve One initially shows weaker floral notes during slurping, but as temperature changes, the mid-palate sweet-sour sensations and flavor layers gradually become apparent. In the finish, distinct tea-like notes and honey sweetness can be clearly detected. However, the overall curve exhibits overly pronounced acidity throughout the cupping experience. Curve Two presents prominent floral aromatics and flavors from the initial slurp. As temperature changes, the mid-palate acidity softens while caramel sweetness emerges. In the finish, nut and cocoa aromas become more pronounced. Overall, it presents distinct flavor layers with a substantial, balanced mouthfeel.

Brewing Guide

After cupping, we found both curves performed well. We brewed separate batches using each curve to see if they would perform similarly in pour-over brewing.

Recommended Brewing Method: Pour-over

Dripper: Hario V60

Water Temperature: 90°C

Coffee Dose: 15g

Brew Ratio: 1:16

Grind Size: Medium-fine (BG 6k: 58% retention on China standard #20 sieve)

Brewing Technique: Pulsed extraction

Start with 34g of water for bloom for 40 seconds. Using a small water stream, pour in circles to 127g, then segment. When the water level drops to just before exposing the coffee bed, continue pouring to 240g and stop. When the water level drops to just before exposing the coffee bed again, remove the dripper. Extraction time from bloom start: 2'00".

Flavor Profile

Curve One: Entry reveals dark plum acidity and berry notes. As temperature changes, nutty aromatics, caramel, and cream emerge. The mouthfeel shows distinct citrus acidity.

Curve Two: Entry reveals citrus, berry, and cherry tomato notes. As temperature changes, caramel sweetness and subtle fermentation aromatics emerge. The finish features floral and nutty cream aromatics. The mouthfeel is smooth and clean.

Conclusion

Through both cupping and brewing, we found that the adjusted Curve Two better expresses the flavor profile of this Pink Bourbon. Of course, flavor descriptions vary by individual and are influenced by water temperature and brewing methods. This cupping report provides descriptions limited by the flavor wheel under identical brewing equipment and parameters, intended for reference purposes.