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The Impact of Blooming and Its Duration on Coffee Brewing (Part 1)

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, We've conducted numerous experiments sporadically in our shop, but never organized the results systematically. Over time, many of the theories and experimental findings we discovered have faded from memory. Therefore, FrontStreet Coffee's team decided to conduct rigorous experiments with minimized deviations, and organize the data and results to share with everyone, helping us remember better and allowing everyone to benefit together.

We have conducted numerous experiments sporadically in our shop, but we had never systematically organized the results. As time passed, many of the theories and experimental findings gradually faded from our memory. Therefore, FrontStreet Coffee's team decided to conduct a rigorous experiment with minimal deviation, organizing and sharing the data and results with everyone. This helps reinforce our own understanding while inviting collective discussion.

The Impact of Blooming and Its Duration on Coffee Brewing (Part 1)

Introduction to Blooming in Pour-Over Coffee

We decided to start our discussion with blooming in pour-over extraction—the crucial beginning of the pour-over process. How much does blooming actually affect coffee brewing? What happens if we don't bloom? How do short versus long blooming times reveal different flavor profiles? Beyond sensory aspects, how do they affect extraction rates? This experiment addresses two main questions: First, the difference between blooming and not blooming in coffee brewing; Second, the differences between 20-second, 40-second, and 60-second blooming times. We will organize the experimental results into a table below for clearer and more intuitive comparison.

Experimental Methodology

To minimize human factors, we first conducted a preliminary experiment using the Clever Dripper. This experiment primarily focuses on obtaining basic data. We designated this as the first group of experiments.

Preparation for the First Experiment:

Before conducting formal pour-over experiments, we utilized the more consistent Clever Dripper for preliminary preparation experiments to obtain reference data conclusions, enabling more accurate predictions for the formal experimental results.

Experimental Procedure:

1. Weigh 12g of coffee beans, grind using Fuji (ghost tooth) grinder setting 2.5# for use

2. Prepare sufficient 92°C hot water

3. We divided this experiment into four subgroups (A, B, C, D), using the same amount of water but with different blooming times.

Group A: Add 12g of coffee grounds to the Clever Dripper, pour 216g of hot water all at once, cover with lid and let stand, total brewing time 4min;

Group B: Add 12g of coffee grounds to the Clever Dripper, first pour 40g of hot water for 20-second bloom, then continue pouring to 216g, cover with lid and let stand, total brewing time 4min;

Group C: Add 12g of coffee grounds to the Clever Dripper, first pour 40g of hot water for 40-second bloom, then continue pouring to 216g, cover with lid and let stand, total brewing time 4min;

Group D: Add 12g of coffee grounds to the Clever Dripper, first pour 40g of hot water for 60-second bloom, then continue pouring to 216g, cover with lid and let stand, total brewing time 4min;

Experimental Results:

Results Analysis:

Based on the comprehensive experimental results above, as blooming time increases:

● Coffee concentration and extraction rates decrease accordingly. Analysis of reasons:

1. When total brewing time is fixed at 4min, as blooming time increases, the actual extraction phase time gradually decreases;

2. During blooming, the coffee grounds in the dripper inevitably experience temperature drop. The longer the blooming time, the greater the temperature decrease, and when water is added again, the water temperature in the kettle also decreases to some extent. Therefore, throughout the brewing process, the extraction temperatures in Groups A, B, C, and D of the Clever Dripper decrease sequentially.

● As blooming time increases, acidity decreases while sweetness and viscosity are enhanced. Overall flavor gradually shifts toward later notes and becomes more complex.

Conclusion and Future Plans

In this first experiment, we used the Clever Dripper to practice our pre-designed theme and obtained some basic data about blooming. However, everyone knows that while the Clever Dripper can reduce human factors and provide relatively objective experimental data, it more closely resembles immersion brewing. Therefore, in the next installment, we will conduct pour-over experiments using the HARIO v60 dripper and organize, compare, and review the data and sensory records just as we did in this experiment.

Additionally, while we conduct experiments and derive theories, we won't provide any final conclusions or tell everyone which method is best, because different brewing methods can showcase different flavor profiles. We hope everyone understands these data and uses them as reference when brewing coffee. Different beans, different techniques; different techniques, different flavors. Nothing in the coffee world is absolutely fixed—that's where the joy lies, isn't it?

During this period, if anyone has questions about the experiments, you can raise them through WeChat or Weibo. We will also edit and publish the next installment's data and text as soon as possible.