How to Operate the Stirring Method for Iced Pour-Over? What Water Temperature, Ratio, and Grind Size Does Japanese-Style Iced Coffee Use?

Introduction

Have you ever experienced when brewing coffee that the water in the filter drips very quickly into the lower pot? Or have you encountered filter cup blockage, with water accumulating in the coffee grounds? FrontStreet Coffee will explore today why these phenomena occur.

Grind Size

When encountering similar situations, we would first think of grind size issues. Indeed, overly coarse grinding leads to too fast water flow, while overly fine grinding results in slow water flow or even blockage. However, you should note one point: have you truly mastered coffee grind size? FrontStreet Coffee consistently uses sieve calibration instead of fixed scales because even with the same roast level, different coffee beans ground at the same setting produce inconsistent particle sizes.

For a simple example, FrontStreet Coffee calibrates using a #20 sieve with an 80% pass rate for light roast as the standard. For Yirgacheffe, the grind setting is EK43s #10, while for anaerobically processed Rose Valley and Hanayoru, it's EK43s #9.5. If you apply the grind setting for Yirgacheffe to coffee beans like Rose Valley and Hanayoru, the water flow will accelerate.

Besides the reason of coarseness, another important factor is the wear of the grinder burrs, which directly leads to increased fine particles and is also a major cause of coffee bed blockage.

Drip Coffee Brewers

Have you ever wondered why there are so many different types of coffee drip brewers on the market? Most drip brewers have a structure based on a predetermined shape (conical, trapezoidal, cupcake-shaped) with different flow ribs added to achieve the extraction results desired by the maker.

Some drip brewers have larger drip holes to allow faster water flow, while others have smaller holes to let water and coffee grounds steep for longer periods. The role of ribs is best exemplified by the contrast between V60 and Kono drip brewers.

V60 drip brewers have long ribs and short ribs. The long ribs have a structure spiraling counterclockwise from the bottom upward, while the short ribs share the same direction as the long ribs but start from 2/3 of the height and distribute outward. This feature allows water to flow through the guide ribs into the lower pot, avoiding blockage to some extent.

Kono drip brewers, on the other hand, have straight ribs extending from the bottom to 1/3 of the height, with the upper part having no flow ribs, being smooth and flat. This way, when water moistens the filter paper and it adheres to the brewer, the part without guide ribs forms a seal with the filter paper, making water flow slower. Meanwhile, the lower ribs provide guidance to avoid blockage in the final stage.

Therefore, drip brewers can also control the speed of water flow. Choosing a suitable drip brewer is twice the result with half the effort.

Pouring Technique

If you notice abnormal flow during brewing, you can also use pouring techniques to compensate. For example, if the grind is slightly too coarse, you can reduce the pouring speed to avoid raising the coffee bed. If blockage occurs, you can use a large water flow to stir and bring the fine particles accumulated at the bottom to the surface.

Important Notice :

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Tel:020 38364473