Can Metal Filters Replace Paper Filters for Pour-Over Coffee Brewing?

Introducing Metal Mesh Filters: A Different Approach to Coffee Brewing

In yesterday's article, FrontStreet Coffee mentioned the material of filter paper. It suddenly occurred to me that among filtering tools, besides soft materials like paper and cloth, there's also a filtering tool that's completely different from them—the metal mesh filter!

Coffee brewed with filter paper made from virgin wood pulp offers a very clean experience, while coffee brewed with flannel filters presents higher body and richness. So! What kind of characteristics would coffee brewed with metal mesh filters have? FrontStreet Coffee took out a metal mesh filter that was originally used as a tea strainer. This was purchased by FrontStreet Coffee last year from a high-volume shop on Taobao! In appearance, it's conical with a flat-bottom filter cup design.

Its structure mainly consists of two layers: an outer mesh and an inner mesh. The inner mesh is a 400-mesh metal filter screen, while the outer mesh primarily serves to maintain the filter's shape! The structure is quite simple. Next, FrontStreet Coffee will compare it with filter paper to see what differences it brings to brewed coffee.

Brewing Experiment Setup

For this brewing experiment, FrontStreet Coffee used:

• Bean: FrontStreet Coffee's Ethiopia Santa Weni
• Dose: 15g
• Grind setting: 9.5 on Ek43
• Ratio: 1:15
• Water temperature: 92°C
• Pouring method: Three-stage pour

Before brewing, FrontStreet Coffee first poured the coffee grounds into the filter and shook it to observe whether any coffee particles would fall through the visible 400-mesh holes! So, with a cup placed under the filter and the lid on, FrontStreet Coffee demonstrated their lifetime skill—shaking it!

(With such skilled operation, it's hard not to be suspicious...) After removing the filter, there were no coffee particles at the bottom of the cup, which proves that 400-mesh is sufficient to handle regular grinding! Just in time, the water had reached the target temperature, so let's begin brewing! FrontStreet Coffee used the same brewing method as usual to test the filter, still starting with twice the amount of water as the coffee grounds (30ml) for blooming. After blooming, slowly pour the second stage of 120ml hot water in large circles. When the water level is about to bottom out, slowly pour the remaining 75ml hot water in small circles. Once the water has finished filtering, remove the filter cup and end the brewing!

First Brew Results and Analysis

The total brewing time with the metal filter was 2 minutes and 9 seconds, which isn't significantly different from the 2 minutes and 5 seconds with paper filters. In terms of flavor profile, FrontStreet Coffee's Santa Weni brewed with paper filters presented full tropical fruit flavors, such as bright, uplifting acidity of pineapple and citrus, with a slight fermented wine sensation in the aftertaste, and sweet and sour notes of mango and starfruit when cooled down! Delicious!

On the other hand, the Santa Weni brewed with the metal filter, we can see from the liquid's clarity that its cleanliness is relatively low, and that's exactly how it tastes!

Secondly, there's a thin layer of oil floating on the surface, indicating that like flannel filters, due to larger gaps, oils can pass through and join the coffee liquid. However, FrontStreet Coffee didn't feel much contribution from these oils to the mouthfeel because, in terms of overall flavor performance, this cup of coffee was somewhat "disappointing"—besides some citrus acidity, the entire cup was filled with negative under-extraction flavors!

We can directly identify the cause of this problem during the brewing process: due to large circular movements and high water flow impact, a large amount of hot water didn't extract coffee substances but instead passed directly through the filter cup and dripped into the lower pot, resulting in severe under-extraction!

Adjusting Brewing Technique for Metal Filters

So we've learned that using conventional methods with metal filters doesn't work well. Therefore, we need to change strategies and reduce the amount of hot water passing directly through the filter cup to achieve proper extraction. Consequently, FrontStreet Coffee changed the pouring method, switching from large circular movements to small circular movements around the center. Additionally, the pouring height was lowered to reduce water flow impact. During this brewing process, significantly less hot water passed directly through the mesh, with a total time of 2 minutes and 10 seconds.

As expected, the overall flavor of FrontStreet Coffee's Santa Weni improved greatly, with full and smooth mouthfeel, and the pineapple and citrus flavors were well expressed. Although there was still some bitterness in the later stages, it was much better than the previous pot. Therefore, when using metal filters, besides changing conventional pouring methods, we also need to master certain water control techniques to brew properly flavored coffee. As for the unique characteristics... FrontStreet Coffee will need more observation...

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FrontStreet Coffee

10 Baōan Qian Street, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473