The Importance of Even Blooming in Pour-Over Coffee: Experimental Summary on Blooming Techniques

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The Art of Blooming in Pour-Over Coffee

The first step in pour-over coffee brewing is blooming.

Purpose of Blooming

The purpose of blooming: to release carbon dioxide, increase extraction rate, and reduce channeling effects.

Usually, there are not just one or two methods to achieve this effect. If you simply pour water in a circular motion to let it naturally release carbon dioxide, or if you pour water in a circular motion and then use external assistance. When we compare these two methods together, will there be significant differences in taste?

For this comparison, I used two different blooming methods and two different coffee beans.

Divided into two groups in total:

Except for different blooming methods, all other brewing conditions were consistent. (We tried our best to avoid the impact caused by manual pouring.)

Group One: FrontStreet Coffee Ethiopia Yirgacheffe Kochere Buna Nafaka

Processing method: Washed processing method

Variety: Local heirloom varieties

Altitude: 1900-2100 meters

Using the same coffee bean, compared with different blooming methods:

Method 1: Simple circular pouring to naturally release carbon dioxide

Flavor: Ginger flower, yellow lemon, fruit pulp, Earl Grey tea

With the sweet and sour aroma of ripe yellow lemon as the main tone, other flavors are quickly overwhelmed after a few more sips. The mouthfeel is very smooth, and it gradually becomes more singular as the temperature decreases.

Method 2: Circular pouring with external assistance (tilting at angles and pushing up, down, left, and right)

Flavor: Ginger flower, yellow lemon, orange peel, fruit pulp, Earl Grey tea

Compared to the previous cup, this one has more layers and overall better balance. As the temperature changes, the aftertaste sweetness lasts longer, and the mouthfeel is slightly more viscous.

Group Two: Kenya Thika ASALI

Processing method: Kenya double-washed processing method

Variety: SL28 SL34

Altitude: 1500-1700 meters

Method 1: Simple circular pouring to naturally release carbon dioxide

Acidity dominates, with complex flavors intertwined together

Method 2: Circular pouring with external assistance (tilting at angles and pushing up, down, left, and right)

Clearer, more balanced, and sweeter

Conclusion

Before brewing, I didn't set up which method would bring better results. If we look at this matter from a simple perspective, we'll find a significant difference. In both groups, the total extraction time was significantly extended when external assistance was used for blooming.

This makes me suspect that the two cups brewed without external assistance during blooming might have had some particles that weren't fully saturated with water. Because water's inertia follows the path of already-wetted areas, while unsaturated coffee particles, being dry, resist and cause channeling effects. This allows water to flow quickly through channels, resulting in lower extraction concentration for some parts, increasing extraction unevenness, leading to shorter total extraction time and incomplete extraction, making the coffee taste less balanced, more singular, and more acidic.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473