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Does Wetting or Not Wetting Coffee Filter Paper Affect Extraction? Which is Better: Natural or Bleached Filter Paper?

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, Professional coffee knowledge exchange. For more coffee bean information, please follow Coffee Workshop (WeChat public account: cafe_style). Introduction: With the continuous development of specialty coffee, in addition to the diverse coffee filter cups, filter papers have also been continuously innovated. From the size of filter papers to

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Introduction

As specialty coffee continues to evolve, not only have coffee filter cups become diverse, but filter papers have also undergone continuous reform. From the size and shape of filter papers to the treatment of the paper itself, the variety of filter papers available can be overwhelming, making it difficult to know how to choose. In this article, FrontStreet Coffee will discuss which shapes of filter papers are suitable for which filter cups and whether it's necessary to wet filter paper when making pour-over coffee.

Shapes of Coffee Filter Papers

Common filter paper shapes include cone-shaped, fan-shaped (trapezoidal), and wave-shaped (cake cup-shaped). Different shapes of coffee filter papers correspond to differently designed filter cups. Common filter cups are generally divided into cone-shaped filter cups, fan-shaped filter cups, cake filter cups, and origami filter cups.

Cone-Shaped Filter Papers

These have a 60° angle and are suitable for single-hole cone-shaped filter cups such as V60, KONO, Infinity Cross Star, Ice Pupil, and Strawberry filter cups. Cone-shaped filter papers come in models 01 and 02. Model 01 is suitable for 1-2 servings, while model 02 is suitable for 2-4 servings.

Trapezoidal (Fan-Shaped) Filter Papers

These are fan-shaped and suitable for Kalita, Melitta, and Clever Dripper. Trapezoidal filter papers come in models 101 and 102. Model 101 is suitable for 1-2 servings, while model 102 is suitable for 2-4 servings.

Wave (Cake Cup-Shaped) Filter Papers

These look like traditional paper cupcake liners, featuring a three-dimensional structure with a flat bottom and uniform wave-like pleats around the sides. They are used with Kalita Wave, Bonavita four-hole cake filter cups, and origami filter cups. Wave filter papers come in models 155 and 185. Model 155 is suitable for 1-2 servings, while model 185 is suitable for 2-4 servings.

Choosing the Right Shape and Size of Filter Paper is Important!

The shape and size of filter paper determine how well it fits with the filter cup. When filter papers don't match the shape of the filter cup and cannot fit perfectly, gaps can easily form between the filter paper and the filter cup. This changes the flow-through effect of the filter cup, leading to negative impacts such as uneven coffee extraction.

Thickness of Paper

Different brands of filter papers also vary in thickness, which is determined by the paper's fiber structure. Thickness affects water flow rate. Thin filter papers fit better with filter cups and restore the intended effect of the filter cup, but they shouldn't be as thin as a cicada's wing. Thick filter papers slow down the flow rate but provide better filtration.

How Should We Choose Between Natural Wood Filter Papers and Bleached Filter Papers?

Natural wood filter papers refer to unbleached filter papers, which are light brown and have a paper taste. Bleached filter papers refer to those that have undergone bleaching treatment, appearing white with no obvious paper taste. Regarding the choice between natural wood and bleached filter papers, FrontStreet Coffee tends to prefer bleached filter papers because their paper taste is not obvious and won't affect the coffee's flavor.

You might be concerned about the toxicity of bleached paper. In reality, famous coffee filter paper brands now use advanced enzymatic bleaching, which is different from traditional chemical bleaching. Enzymatic bleaching uses biologically active enzymes and is widely used in the medical field. Therefore, when buying coffee filter papers, be sure to choose from major brands with reasonable prices. Some overly cheap filter papers cannot guarantee quality in terms of material, size, or bleaching technology.

Should Filter Paper Always Be Pre-wetted Before Making Pour-Over Coffee?

Regarding this question, coffee enthusiasts generally discuss it from three perspectives: first, to remove the taste of the filter paper; second, to help the filter paper fit better with the filter cup; and third, to preheat the coffee equipment at the same time.

Regarding removing filter paper taste: As FrontStreet Coffee mentioned above, natural wood filter papers have some paper taste because they haven't undergone bleaching treatment. Therefore, coffee enthusiasts using natural wood filter papers need to wet them to reduce the impact of paper taste on coffee flavor. Enzyme-bleached filter papers don't require wetting since they have little taste to begin with. If you're using chemically bleached papers, wetting is actually meaningless because the chemical taste is stronger than that of natural wood paper. If you smell an uncomfortable odor when wetting, stop using it.

Regarding helping filter paper fit better with the filter cup: In reality, not wetting the filter paper and adding coffee grounds directly can help the paper fit better with the filter cup. Moreover, when blooming with dry filter paper versus wet filter paper, the former has better gas release. Some coffee enthusiasts might say that unwetted filter paper absorbs some coffee liquid during brewing, but wetted filter paper does the same. When comparing brews with the same parameters and techniques, there isn't much difference in taste between coffee made with wetted and unwetted filter paper.

Regarding preheating coffee equipment: FrontStreet Coffee believes that preheating coffee equipment is essential! Rather than saying you preheat equipment while wetting filter paper, it's better to say you wet filter paper while preheating equipment.

Conclusion

Actually, there's no need to纠结 (obsess over) whether to wet or not wet filter paper—just brew according to your own habits. Except for natural wood filter papers which have paper taste issues, the other two types either don't have much impact or absolutely require wetting. If there's a significant difference in flavor between coffee brewed with wetted versus unwetted filter paper, FrontStreet Coffee believes this indicates a problem with brewing technique or parameters, which is what's causing the difference in coffee flavor.

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