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How Does Grind Particle Size Affect Pour-Over Coffee Flavor? Should You Include Fine Particles?

Published: 2026-01-28 Author: FrontStreet Coffee

Last Updated: 2026/01/28, Grinding is crucial for coffee, as particle size directly affects the efficiency of hot water extraction. Theoretically, the more uniform the coffee particles, the more consistent the overall extraction efficiency, resulting in better coffee flavor. Experimental Design The variable in this experiment is the uniformity of coffee particles, so two groups were established: Group A and Group B. The grind size has an 80% pass-through rate on a #20 standard sieve.

Coffee grinding experiment equipment setup

Grinding is extremely important for coffee, as the size of coffee particles directly affects the efficiency of hot water extraction from the coffee. Theoretically, the more uniform the coffee particle size, the more consistent the overall extraction efficiency will be, resulting in better coffee flavor.

Experimental Design

The variable in this experiment is the uniformity between coffee particles, so two groups were established: Group A and Group B.

Group A	Group B
Grind size: 80% pass-through rate on #20 standard sieve, meaning it contains 20% of coarse particles larger than 850 microns and a small amount of extremely fine particles smaller than 250 microns.	Using the same grind size as Group A, but with more coffee beans ground. Particles larger than 850 microns and smaller than 250 microns were sifted out through a sieve, selecting only coffee particles in the 250-850 micron range.

Coffee brewing parameter measurements

Other brewing parameters remained consistent, as follows:

Parameter	Value
Coffee amount	15g
Coffee-to-water ratio	1:15
Water temperature	91°C
Dripper	V60#01

This experiment used coffee beans from FrontStreet Coffee's Colombia Paraiso Strawberry, with specific information as follows:

Origin	Colombia, Cauca
Estate	Paraiso Estate
Altitude	2050m
Variety	Castillo
Processing	Double Anaerobic Washed

Three-stage pour-over brewing process

Brewing Process

Both groups used a three-stage brewing method. First, the filter paper was moistened to preheat the dripper. In the first stage, 30g of water was poured and allowed to bloom for 30 seconds. In the second stage, water was poured in a circular pattern from the center outward to 125g, then stopped. When the coffee bed had dropped by half, the third stage was poured to 225g. Once all the coffee liquid had flowed from the dripper into the serving pot, the dripper was removed to complete the extraction.

Coffee flavor comparison tasting setup

Flavor Comparison

Parameter	Group A	Group B
Extraction Time	1'50"	1'57"
Flavor	Rich strawberry aroma in fragrance, with flavors of strawberry candy, yogurt, and peach. The texture is substantial and rich.	Compared to Group A, the aroma features strawberry with osmanthus notes, with main tones of strawberry and honeydew melon. The flavor is more concentrated, the mouthfeel is clean without off-flavors, and the aftertaste is citrus.

From the extraction times in the table, it can be seen that Group B's flow rate is slower than Group A's. Many people might think that more uniform particles would be less likely to cause clogging. The reality is that both groups used the same grind setting, but Group B removed large coarse particles and extremely fine particles on this basis, so in reality, Group B's overall grind size is slightly finer than Group A's (with a significant difference of 20% of particles larger than 850 microns).

Group A already demonstrated the characteristics of this bean very well in its flavor profile, while Group B's smaller variation in particle size greatly compensated for the extraction inconsistency between coarse and fine particles. This creates a very clean sensation when drinking, while the flavor remains uncompromised. It's truly an excellent adjustment technique (though somewhat wasteful of beans).