How Fine Should You Grind Coffee for Pour-Over? Calibration Guidelines for Grinder Settings

When analyzing pour-over coffee knowledge, FrontStreet Coffee emphasizes the importance of parameters. With the right water temperature, right grind size, right coffee-to-water ratio, and right pouring method, you can definitely brew the right coffee.

This "right" is not the only answer, but rather a value that FrontStreet Coffee considers very friendly for beginners during its exploration process—a simple way to reach the destination.

As you explore the world of pour-over coffee, everyone will try to experiment with different techniques. After thoroughly understanding the parameters and knowing what changes in the coffee flavor occur when modifying them, you will inevitably develop your own method (brewing mindset).

Among the parameters, grind size is often problematic. While other parameters are relatively easy to determine, grind size seems somewhat elusive. Although various coffee shops try their best to help customers understand grinding, FrontStreet Coffee uses a #20 sieve for calibration.

A #20 sieve can only separate particles larger than 0.85mm from those smaller than 0.85mm, but it cannot distinguish whether smaller particles (0.3mm) or medium particles (0.6mm) predominate. Additionally, the performance differences among everyone's grinders are enormous, making standardization difficult.

For example, FrontStreet Coffee uses the EK43s, which offers high grinding uniformity with extremely few fines. Under these conditions, when FrontStreet Coffee mentions a grind size with 80% pass-through rate on a #20 sieve, the particle size distribution mainly consists of particles around 0.6mm, with the coarsest particles not exceeding 1mm and being very few in number.

In contrast, some lower-performance grinders produce coffee particles with significant size variations, showing obvious coarse and fine particles. When using the same sieve with 80% pass-through rate and identical other parameters, it's expected that the resulting brew might have off-flavors or lack taste.

Solutions for Grind Issues

The best solution is to upgrade to a higher-performance grinder for a one-time fix.

If this approach isn't feasible, you can only make adjustments through parameter changes. If you're using a hand grinder, the most significant characteristic is the pressure that causes coffee beans to crack and produce fines. Therefore, in theory, grinding faster reduces these crack-induced fines.

Next, based on your established 80% pass-through grind size, grind your coffee 2-3 settings coarser, then use a sieve to separate the coffee particles. Return the particles larger than 0.85mm to the grinder, adjust the setting 2-3 settings finer, and grind again. This will result in relatively less variation in coffee particle sizes.

If you frequently experience off-flavors when brewing coffee, the main reason is usually excessive fines. A smaller portion is caused by high water temperature, strong agitation, or long extraction time. Therefore, when off-flavors appear, the adjustment direction includes these factors: lower water temperature, gentler pouring, or reduce extraction time.

Managing Coffee Fines

Is the most common method of sieving out fines the most practical? This question should also be analyzed situationally. If the water flow is simply slow (with minor blockage) and there are no significant negative flavors in the final cup, you can completely ignore it. If bitterness and off-flavors do occur due to fines, you can proceed with sieving the coffee grounds.

You can also use a single-pour technique to quickly add all the water, raising the height of the coffee bed and washing the fines toward the filter cup walls, which is also effective.