What Is the Ideal Grind Size for Pour-Over Coffee? How to Determine If Your Coffee Grind Is Correct

Grind size has always been a parameter that's difficult to express in words. When people talk about coffee grind size, they generally use visual comparison methods, scale reference methods, and even the sieve calibration method used by FrontStreet Coffee, but all of these have some limitations.

Visual Comparison Method

The visual comparison method, which we often refer to as "raw sugar size" or "fine sugar size," uses common objects to compare the coarseness of coffee grounds. However, this is the most unreliable method. First, it's difficult for human eyes to distinguish differences between small objects, and second, our eyes are easily attracted to focal objects, thus ignoring other details.

For a simple example, many friends who visit FrontStreet Coffee, after seeing the grind size of the pour-over coffee grounds, often ask a similar question: "I notice you grind quite finely, but why doesn't the water flow slowly or get clogged during brewing?"

There are usually two situations for those who ask this question. First, if they use this grind size to brew coffee, it's likely that the water flow will be slow or clogged. Second, their grind size for brewing coffee is coarser than FrontStreet Coffee's.

This is actually your eyes deceiving you. If using a hand grinder to grind coffee, there will inevitably be some seemingly larger particles. Compared to FrontStreet Coffee's ground coffee, which has fewer of these large particles, and combined with the phenomenon of amplifying focus points based on memory, you might mistakenly think your grind size is coarser.

Unless trained extensively, judging coffee coarseness by sight alone can result in significant errors. Similarly, the same principle applies to using touch to determine grind size.

Scale Reference Method

This method uses grinder scale values to define the coarseness of coffee grounds. Typically, commonly used grinders are used as references, such as Fuji's 4 scale, EK-43's 7 scale, C40's 26 marks, and so on.

The drawbacks are obvious. If you're using an obscure grinder, it's likely that communication will be difficult. Furthermore, even two grinders of the same brand and model may not produce the same grind at the same scale setting. For example, FrontStreet Coffee once tested two new Flying Pony grinders, where one grinder's 4.5 setting produced the same coarseness as the other's 5 setting.

Sieve Calibration Method

This is FrontStreet Coffee's method for calibrating grind size for cupping, pour-over, and other brewing methods. FrontStreet Coffee uses a standard #20 sieve with a mesh size of 0.85mm. This sieve is used to determine coffee grind coarseness and serves a different purpose from sifters used to remove fine particles.

The specific operation method is to use 10 grams of coffee beans (or multiples of 10 for easy calculation - the more grounds used, the more accurate the data). Select a grind setting, grind the coffee, place it in the sieve, and shake horizontally until particles no longer fall significantly (usually 3-5 minutes). Then weigh the powder that fell through and divide by the total powder weight to get the sieve pass rate. For example, if 5g of powder passes through the sieve, the pass rate is 50%. To reach an 80% standard, you need to adjust to a finer grind setting and remeasure until you achieve 80%.

Of course, this method also has limitations. Using a 0.85mm sieve can only separate coffee grounds larger than 0.85mm from those smaller than 0.85mm, and we can only know the ratio of these two groups. However, we cannot determine how coarse the coarsest particles are or how fine the finest particles are. Therefore, when using this method with lower quality grinders, even if you achieve the required sieve pass rate, the flavor of the brewed coffee may still be unsatisfactory.

Is There a More Accurate Method?

Actually, yes. If one sieve can't solve the problem, then add more sieves. This involves a concept called "particle size distribution."

Even the best grinders on the market cannot produce coffee grounds that are all identical in size - there will inevitably be some coarser and some finer particles. If we set ranges: particles >0.3mm as very fine, 0.3-0.6mm as medium-fine, and 0.6-0.85mm as medium particles, and then use 0.3mm, 0.6mm, 0.85mm, and 1mm sieves to separate these coffee grounds and calculate the percentage in each range, this is what we call "particle size distribution." The ideal pour-over grind state is when the 0.6-0.85mm particles have the highest percentage, with other size ranges distributed toward the middle.

In simple terms, the more concentrated the particle size distribution, the more uniform the coffee grind. When the particle size distribution is scattered, it indicates uneven grinding. To remedy this, some very fine and very coarse particles may need to be discarded.

But in reality, using this method to determine grind size is too cumbersome. Is there a simpler approach? Yes, it's pragmatism. Perhaps the above knowledge might be fascinating for friends who enjoy researching coffee, but for someone who just wants to know if the current grind setting is suitable for pour-over, it seems impractical.

Why does FrontStreet Coffee mention an 80% pass rate with a #20 sieve when sharing pour-over coffee grind sizes? This is based on FrontStreet Coffee's entire brewing framework. Grinding slightly coarser or finer than this can still produce good coffee. Brewing coffee can be understood as very complex or very simple.

If we use a simple understanding to determine whether coffee grind size is appropriate, we can combine FrontStreet Coffee's three methods. For example, if you've purchased a grinder, you can first ask the seller for a recommended grind setting. They'll usually give you a range, so your ground coffee won't be too far off.

Then you can visually inspect whether it has a coarse texture or a dense powder feeling. This can be distinguished through visual inspection and touch. The grind size used for pour-over has a coarse particle texture.

If conditions allow, you can use sieves to specifically determine the coffee's pass rate, which can also connect your visual judgment with data.

Regardless of particle size distribution, you ultimately need to test during the brewing stage. You can use water flow speed and extraction time to determine if the coffee grind size is appropriate. For example, when brewing with 15g of coffee grounds, if the water flow speed is uniform and moderate, and the extraction time is around 2 minutes, then the grind size is appropriate. If the water flow is slow but still uniform, and the total extraction time exceeds 2.5 minutes, then the grind might be too fine. If the water flow is relatively fast and the extraction time is less than 1 minute and 40 seconds, the grind might be too coarse. If the water flow gradually slows down, it might be due to excessive fine particles.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473