In grinder reviews, particle size distribution analysis is a practical way to link grind performance to what you taste in the cup.
Different distributions can influence clarity, perceived sweetness, flavor separation, and extraction balance.
In this video, Daryl Bueno—a coffee content creator known for clear, easy-to-follow explanations—tests the Femobook A2 by measuring its particle size distribution within a pour-over grind range.
Using sifting and precision weighing, he documents what the A2’s distribution looks like and shares how he relates those results to flavor.
Below is a summary of his workflow, measurements, and key flavor observations, so readers can more easily understand the A2’s grinding characteristics.
【Particle Analysis Setup: Two-Layer Sifting + a Precision Scale】
For this test, Daryl used 15 g of medium-roast coffee and set the Femobook A2 to a pour-over setting of 60.
After grinding, he sifted the grounds with a Kruve sifter using 1100 μm and 300 μm screens to split the dose into three ranges:
-
Above 1100 μm: coarse grounds (“boulders”)
-
300–1100 μm: medium grounds (“mids”)
-
Below 300 μm: fine particles (“fines”)
He shook the sifter for 30 seconds, then weighed each fraction on a precision scale to show the A2’s particle distribution in a straightforward, measurable way.
【A2 Particle Distribution: 64% Coarse, 36% Medium, 0.5% Fine】[1]
After sifting and weighing, Daryl’s results show a distribution dominated by coarse and medium fractions:
-
Coarse: 9.7g (≈ 64%)
-
Medium: 5.4g (≈ 36%)
-
Fine: 0.084g (≈ 0.5%) [2]
That puts coarse to medium at roughly a 2:1 ratio, with very few fines.
Frank
Femobook's Editor
1. The percentages above are calculated from the gram weights Daryl shows in the video and are provided to help visualize the distribution.
2. Adding the three fractions together gives a total 0.184g above the original 15g dose. This can happen when coarse and medium weights are displayed to one decimal place (rounding can accumulate), and milligram-level readings on a precision scale can also shift slightly with environmental factors—this is normal.
【Coarse-Forward, Minimal Fines: Tends to Brew a Clean, Clear Cup】
Coarse grounds make up the biggest share here—about 64%. After sifting, Daryl notes the coarse fraction looks pretty consistent, with not much variation from particle to particle.
His takeaway: when a grind skews coarse and produces very few fines, it’s often easier to brew coffee that tastes cleaner and clearer.
【Medium Grounds Brings Sweetness】
The medium fraction comes in at 36%, about half the weight of the coarse fraction. In Daryl’s words, mids are what bring sweetness to the cup.
【Fines at Just 0.5%: Lower Risk of Over-Extraction 】
Fines measured 0.084 g, or about 0.5% of the total.
During the sifting process, Daryl remarks that he’s seeing very little fine particles—and the scale readings support that observation.
He also notes that when fines are this low, there’s less chance of over-extraction and a lower risk of astringency.
【Femobook A2 Review: Particle Size Analysis & Flavor Impact】
Using sieve-based measurements, Daryl’s test puts the Femobook A2 (in a pour-over range) at roughly 64% coarse, 36% medium, and 0.5% fine, with coarse to medium close to 2:1 and very few fines overall. [1]
He emphasizes that particle size distribution shapes how coffee tastes.
Based on his measurements, he notes that the A2’s coarse-forward distribution with very few fines is likely to produce a clean, high-clarity cup, while the medium fraction supports perceived sweetness. [2]
At the end of the video, Daryl sums it up like this:
“After learning the particle size distribution, I’m even more impressed by how Femobook engineered the burrs on the A2.”
Frank
Femobook's Editor
1. Particle size distribution results can vary depending on the analysis method, the equipment used, the sieve sizes and cutoff points, as well as the coffee itself (including origin/variety) and roast level, among other factors.
2. Coffee flavor is influenced by many variables, and particle size distribution is only one factor.
** This article reflects the presenter’s measurements of particle size distribution under his specific test conditions and is provided for reference only. **
Note: The content above is excerpted from the YouTube video by《Baryl Bueno》.
