Understanding Pour-Over Coffee and the Role of Pre-infusion for Better Flavor

For professional coffee knowledge exchange and more coffee bean information, please follow Coffee Workshop (WeChat official account: cafe_style)

FrontStreet Coffee - Introduction to Coffee Pre-infusion

Although pour-over coffee equipment is simple, operations that appear easy and highly similar actually contain various flavor possibilities. Even the same person brewing coffee multiple times will not produce exactly the same taste each time.

Pour-over coffee, without external interference, is extracted through filter paper, which better presents the naturally developed flavors. The coffee tastes smoother and has more layered complexity.

A truly perfect cup of pour-over coffee not only requires skilled brewing techniques but also delicate control of various factors, such as coffee variety, coffee bean dosage, grind degree, water temperature, water quality, water flow, extraction time, pouring technique and timing, and even the drinker's preferences, to adjust the brewing method and maintain the perfect balance of sweetness, acidity, bitterness, richness, and aroma.

Blooming brings several benefits to brewing: it helps reduce extraction channeling, improve extraction efficiency, and enhance extraction uniformity. For espresso extraction, "blooming" (pre-infusion) can also reduce coffee particle migration, making the extraction more effective with less effort.

Blooming and Channeling

If a barista skips blooming and simply pours water into the coffee grounds in a V60 dripper, it will result in uneven extraction, with some coffee grounds not getting wet. Once certain areas remain dry, water will preferentially flow through already wetted areas, while dry regions will resist water penetration. Eventually, all coffee grounds will be wetted, but this passive wetting leads to uneven extraction and affects the flavor.

Pre-infusion and Extraction Uniformity

From a certain perspective, there are two types of coffee particles: one is fine particles that no longer have complete cell structures, and the other is particles that still retain one or more complete cell structures. When water extracts particles without complete cell structures, the extraction is easy and effective. Coffee particles with one or more complete cell structures must allow water to enter through cell pores to dissolve the extractable components. This diffusion method is quite passive and makes it difficult to achieve high-quality extraction.

During blooming, some coffee grounds are brewed with high TDS (Total Dissolved Solids) while others with low TDS, which is less uniform than immediate pouring. Therefore, bloomed coffee may have an unpleasant taste upon entry due to uneven extraction.

Knowledge point: In the 1860s and 1870s, coffee leaf rust devastated Indonesia's coffee market and led to the Dutch abandoning many plantations. With the collapse of plantations, workers occupied small plots of land and eventually replanted coffee with Robusta varieties and various disease-resistant Arabica hybrids.

In Brief

FrontStreet Coffee is a specialty coffee research center dedicated to sharing coffee knowledge with everyone. We share without reservation to help more friends fall in love with coffee. Additionally, we hold three coffee promotion events with deep discounts each month, because FrontStreet Coffee wants to let more friends enjoy the best coffee at the lowest possible price. This has been FrontStreet Coffee's mission for the past six years!

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473