Hey guys, welcome back. So today we’re going to be talking about a very important element of coffee brewing: grinders. We will discuss the importance of a good coffee grinder across filter and espresso brewing methods. Additionally, we will conduct tests using different grinders for various brews, then evaluate the extraction and overall taste of each brew.
Why Grinders Deserve the Spotlight
In the world of speciality coffee, it’s easy to get swept up in conversations about water chemistry, brew ratios, or the latest pour-over dripper. But if there’s one piece of equipment that quietly holds everything together, it’s the coffee grinder.
Why? Because the grinder determines your particle size distribution, and this, in turn, defines your extraction. A better grinder offers more uniformity, fewer fines (ultra-small particles that over-extract), and better clarity in your cup.
This isn’t just anecdotal. Jonathan Gagné’s seminal book The Physics of Filter Coffee devotes an entire chapter to the role of grinding (Chapter 3, pages 45–70), and his conclusions are clear: grinder performance is one of the most critical factors in brewing high-quality coffee.
What Makes a Grinder “Good”?
Let’s break it down using Gagné’s insights and some real-world experience.
1. Particle Size Distribution
A good grinder produces a narrow and consistent distribution of particle sizes. That means fewer fines and boulders (very large particles), both of which wreak havoc on extraction.
Inconsistent particle sizes cause uneven extraction: fines extract quickly and can cause bitterness, while boulders remain under-extracted, leading to sourness and a lack of complexity. Gagné illustrates this with laser diffraction graphs showing the stark contrast between high-end burr grinders and entry-level models.
2. Burr Geometry and Alignment
One of the revelations from The Physics of Filter Coffee is how important burr alignment is — especially in flat burr grinders. Misaligned burrs produce a wider particle spread, reducing clarity and increasing bitterness. Properly aligned burrs, especially those with modern high-precision geometries (like those from SSP), can dramatically improve cup quality by narrowing the grind size distribution.
3. Grind Retention and Heat Transfer
Another overlooked factor is the heat generated during grinding. Excessive heat, often from high-speed grinders with poor ventilation, can cause premature extraction or even degrade volatile aromatic compounds. Similarly, grinders that retain a lot of old coffee grounds introduce stale flavours. Low retention and slow-speed grinders, particularly those designed for single dosing, mitigate these issues effectively.
Testing Grinders Across Brewing Methods
To really answer the question — does a good grinder matter? — We conducted side-by-side brews using three different grinders:
1. Blade Grinder (entry-level) – Krupps coffee grinder
2. Conical Burr Grinder (mid-tier) – Fellow Opus
3. Flat Burr Grinder (high-end) – Mahlkonig EK43s
We used the same coffee — a washed Ethiopian heirloom — and brewed it using two methods:
- Filter – Origami Air S – (17g, 270g out)
- Espresso – La Marzocco Linea PB – (18g in, 36g out in 28 seconds)
Origami Air S Results
Blade Grinder: Heavy sediment in the cup, muddy flavours, and an indistinct profile. Over-extracted bitterness on the tongue with some sourness underneath.
Conical Burr: Improved clarity, though still some muddiness. Brightness showed through but was muted by a lingering bitterness.
Flat Burr: Clear, sparkling cup with distinct florals and citrus. Very clean finish and great balance. Exactly what we expect from this coffee.
Espresso Results
Blade Grinder: Choked the machine — shot didn’t run properly. Inconsistent puck resistance and channeling led to both sourness and bitterness.
Conical Burr: Acceptable shot, but lacking in body and sweetness. Some channeling likely due to particle inconsistencies.
Flat Burr: Syrupy shot with vibrant acidity, strong sweetness, and silky mouthfeel. Extraction was even and repeatable.
So… Does a Good Grinder Matter?
Absolutely — in fact, it may matter more than almost any other single piece of gear in your setup.
Gagné puts it plainly: investing in a grinder that delivers consistent particle sizes with minimal fines is one of the most impactful steps you can take toward better coffee. Whether you’re brewing filter or pulling shots of espresso, the clarity, balance, and sweetness in your cup are directly tied to how your coffee was ground.
Summary
If you’re just starting out, don’t feel like you need to buy the most expensive grinder on the market right away. But do know that your grinder sets the ceiling for your brew quality. You can have the best beans and perfect water, but if your grind is all over the place, your cup will be too.
Start with the best grinder you can afford, and if you’re serious about coffee, consider upgrading to a high-precision burr set down the line — especially if you love clarity in filter or consistency in espresso.
and thats it! Thank you so much for taking the time to read todays article, we really appreciate it! We hope its helped you make that critical decision on updating your coffee brewing set up!
If you’re a complete beginner why not check out our articles on pour over for beginners and dialling in espresso for beginners.
Until next time, thanks again!
Catch you on the next one!
