How to Use a Coffee Grinder Sieve? How to Use a Sieve? What Are the Requirements for Grind Size in Pour-Over Coffee?

The Dilemma of Fine Coffee Grounds

A friend recently shared his frustration with FrontStreet Coffee. He noticed that his coffee brewing was experiencing slow water flow, and the flavor tasted somewhat complex and not clear enough. So he purchased a flour sifter to remove the fine grounds. While this solved the water flow issue, the coffee tasted flat and lifeless. This completely baffled him.

Fine Grounds: A Double-Edged Sword

The "fine grounds" mentioned here refer to "ultra-fine particles," with a consistency similar to espresso grind size, smaller than 250 microns. No matter how expensive the grinder, coffee grounds will always contain these ultra-fine particles - this is unavoidable. However, high-quality grinders produce fewer fine grounds, while poor-quality grinders generate more.

Because these fine particles are much smaller than normal pour-over grind particles (600-800 microns), they release flavor compounds faster than coarser grounds during extraction. This results in a higher extraction rate for the fine particles compared to the coarser ones. This microscopic extraction unevenness actually makes the coffee flavor more complex and layered.

Of course, this only works when fine grounds constitute a small portion of the total coffee mass, where they don't overwhelm the entire cup. When the quantity of fine particles is excessive (when grounds smaller than 250 microns make up more than 10% of the total mass), the first problem is that the fine particles clump together and block the drainage holes, causing slow water flow. Additionally, excessive fine grounds combined with longer extraction times lead to bitter and unpleasant flavors. Essentially, this "extraction unevenness" has become imbalanced.

The Flour Sifter Approach

To address this phenomenon, the foolproof solution is to upgrade to a higher-quality grinder, though this option requires a considerable budget and typically requires careful consideration. Another cost-effective alternative is to invest in a fine-ground sifter. After grinding the coffee beans, you manually remove the fine particles using a sieve, which can solve the problems caused by excessive fines.

However, this approach also eliminates the pleasant surprises that fine grounds can bring. Because manual sifting removes the fine particles too thoroughly, the resulting coffee will have higher clarity but simultaneously exhibit watery characteristics and flat flavors.

Sometimes, sifting coffee grounds can lead to mental miscalculations. FrontStreet Coffee once encountered an interesting case: a friend weighed 15g of coffee beans, ground them, sifted out the fine particles, and began brewing. He originally used a 1:15 ratio and indeed poured 225ml of water, but after completing the pour, he forgot that the 15g of coffee grounds now weighed less than 15g after removing the fines. While this was a very rare incident, it reflects how added steps can introduce more uncertainty.

Reincorporating Fine Grounds?

To solve both the drainage blockage issue and avoid flat flavors, many people have come up with creative solutions. One approach involves reincorporating the sifted fine grounds back into the brew, where the timing of addition is crucial. The method works like this: first, use the sifter to separate the fine particles, then proceed with normal segmented pouring. When preparing for the final pour, add the fine grounds to the filter cup and pour the last segment of water.

This approach actually prevents the bitter and unpleasant flavors that come from over-extracting fine grounds for too long. It preserves the flavor contribution from the fine particles while avoiding the drainage blockage issue. (More importantly, it doesn't waste coffee grounds!)

Using Your Sitter Wisely

You shouldn't always sift when experiencing slow water flow. Typically, you only need to use a sifter when you notice complete blockage with no water flow, or when the used coffee bed has a sludge-like consistency - these are clear signs of excessive fine grounds.

Sometimes slow water flow is caused by certain habits. For example, when using an electric grinder, some fine coffee particles always stick to the dispensing chute. When these grounds are tapped into the portafilter, they end up on top. When poured into the filter cup, they settle at the bottom, meaning even a small amount of fine particles can block the drainage holes.

Alternatively, constantly shaking the portafilter can cause the coarse and fine grounds to separate. If you observe carefully, freshly ground coffee consists of larger particles surrounded by layers of fine particles. Without shaking, the coarse and fine grounds will separate, with the fine particles clumping together and slowing water flow.

Another scenario: during the pour after blooming, water is typically poured in circular motions from center outward. This pouring method pushes the coffee bed toward the edges, forming a "coffee wall," and the majority of fine particles get pushed to the filter paper edges, which doesn't interfere with water flow speed. However, if you wash the fine particles from the coffee wall back into the main bed, this will also cause slow water flow.

Important Notice :

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