How to differentiate 3 generations of Kōno Filters and Pour-Over Methods

Kōno (コーノ) is a well-known coffee equipment brand in the Japanese coffee community.

Founded in 1925,  Kōno (Coffee Syphon Company) developed the world's first syphon coffee maker and then designed Japan's first conical filter cup in 1973.This groundbreaking accomplishment allowed for the utilization of paper to craft a filter akin to flannel, elevating the coffee's flavor profile. Subsequently, Kōno innovated further by designing filter cups tailored for both seasoned coffee connoisseurs and beginners in the art of pour-over brewing, earning widespread acclaim from coffee aficionados in Japan and globally.



With so many options available, it can be overwhelming to differentiate betweenKōno filter cups. Let's break it down in one article to make it crystal clear!

Japanese classic dripper KONO dripper MDN-21 & MDK-21 - SOLOBITO


Types of Kōno filter

Kōno categorizes all its coffee drippers under the term "filter." Compared to conical filter  from other brands, Kōno's design incorporates shorter ribs underneath, allowing the upper portion to tightly adhere to the filter paper when hot water is poured in. This prevents undesirable foam components in the coffee from flowing laterally towards the cup walls, ensuring that the extracted coffee concentrates naturally in the center and flows down, reducing any unpleasant aftertaste.

Since the introduction of the first MD type in 1973, Kōno has continuously refined its designs. These filters are divided into three categories based on era, design, and flavor profile.


MD-21 (2 cups)

MD-41 (4 cups)

MDN-21(1-2 cups) MDK-21(1-2 cups)
MDK-41(2-4 cups)

Kōno since1925


Material MD-21 acrylic resin
MD-41 PCT resin
Acrylic resin PCT resin
Year of sale 1973 year 2010 2015
Groove (rib) length long middle short
Extraction hole size big middle Small

Extraction speed

quick middle slow
Heat resistance temperature 90℃ 109℃
Target users Barista/Professional Coffee Controller Barista/Those who pursue professional taste Novice/general enthusiast



The Difference Between MDN and MDK

  • The most popular Kōno filters are MDN and MDK types, differing primarily in flow rate.
  • MDK has shorter ribs and smaller extraction holes, resulting in a slower flow rate.
  • Slower flow allows thorough extraction of coffee liquid, preventing off-flavors from the coffee grounds downstream.
  • In typical operation, pour-over enthusiasts can freely adjust flow rate and flavor if hot water flows smoothly.
  • MDN type suits intermediate or professional practitioners for adjustable flow rates.
  • MDK type is suitable for pour-over novices due to less significant flavor changes with slower flow.
  • Flavor profile: MD filters offer light flavor, MDN falls in the middle, and MDK provides rich intensity.
  • Among MD, MDN, and MDK types, MDN is standard for professional pour-over enthusiasts, while MDK allows beginners to brew rich coffee easily.
  • Even ordinary households using electric kettles can brew good-tasting coffee with Kōno filters.
  • Kōno developed all three filters to coexist, catering to various pour-over enthusiasts' preferences without intending to replace old models.
Japanese classic dripper KONO dripper MDN-21 & MDK-21 - SOLOBITO

MDK-21 (left) short rib filter bowl & MDN-21 (right) medium rib filter bowl


Japanese classic dripper KONO dripper MDN-21 & MDK-21 - SOLOBITO

MDK-21 (left) filter cup (small extraction hole) & MDN-21 (right) filter cup (middle extraction hole)

Kono MDK-21 Filter & MDN-21 Filter Filter Bowl - SOLOBITO


MDK hand brewing method

 Recently, Kōno President Masanobu Kono demonstrated on YouTube how to use KONO's third-generation filter cup MDK to brew coffee by hand. Novices can brew the cup according to the instructions, and the coffee brewed can be as good as it looks, rich and medium without any odor.


The famous Japanese classic dripper KONO dripper MDK-21 - SOLOBITO


STEP 1: Drip Water

Start pouring water from the center of the coffee grounds.

Drip-style water pouring doesn't involve waiting for the coffee grounds to bloom for 30 seconds. Instead, the focus is on pouring water directly into the center of the coffee grounds, drop by drop, allowing the water to saturate the grounds and gradually expand.

At this point, white foam will gradually emerge and expand, forming a "mushroom-like" shape. This white foam contains components of off-flavors present in the coffee grounds.

STEP 2: Circular Water Pour

Once the coffee liquid begins to drip into the lower vessel, you can transition from drip-style pouring to circular pouring with a thin stream of water. Start from the inside and move outward, beginning with a circle roughly the size of a five-yen coin, gradually expanding the circle little by little to ensure thorough extraction of the coffee.

Because of the short ribs (water channels) built into the MDK filter, extraction occurs at a slower rate. Therefore, even if you're not very skilled at pouring water, it's not a problem.

As the coffee liquid slowly flows down, it indicates a harmonious coexistence between the coffee grounds and water. The flowing coffee liquid also appears quite thick.

Key Point:

Because the upper half of the MDK filter cup lacks ribs (water channels), it can both prevent impurities or off-flavors in the coffee grounds from being carried downstream and ensure that the filter paper adheres tightly to the filter cup, providing a dual-layer effect to prevent white foam from flowing downward.


STEP 3: Maintain Continuous Water Pouring

When the coffee liquidl reaches 1/3 to 1/2 of the target volume, pour water continuously without interruption. Maintain the water level in the filter cup (do not let it sink) to ensure that the white foam, containing impurities and fine particles, remains on the surface without affecting the coffee's flavor.

The accumulation of coffee grounds at the edge (perimeter) of the filter cup is relatively thin, indicating that the components containing off-flavors have not spread to the periphery.

Completion of Brewing

When the extracted coffee liquid reaches the desired volume, immediately remove the filter cup from the lower vessel.

Stir and enjoy your coffee.