Step 2 · Grind
Coffee grinders: burrs, blades, and why grind size matters
If you upgrade one piece of coffee gear, make it the grinder. It decides how evenly your coffee extracts, and no brewing technique can fully make up for an uneven grind.
Why grinding matters
Water extracts flavor from the surface of coffee particles. Grinding multiplies that surface area, and the size of the particles sets two things at once:
- How fast flavor comes out. Finer particles extract faster.
- How fast water drains. Finer grounds pack tighter, so water flows through more slowly and stays in contact longer.
Both push the same way, which is why a small grind change has such a big effect on taste. But size is only half the story. What really matters is consistency. A mix of big and small particles extracts unevenly: the fine dust over-extracts and turns bitter, while the big chunks ("boulders") under-extract and taste sour. The cup ends up both at once.
Grind fresh. Ground coffee loses aroma within minutes, because volatile compounds and CO₂ escape from all that new surface area.
Blade vs burr grinders
Blade grinders are really choppers: a spinning blade smashes beans at random until you stop. You get dust and boulders in the same batch, and the longer you run it, the more fines and heat you create. They're cheap and better than pre-ground coffee that's gone stale, but hard to brew consistently with.
Burr grinders crush beans between two hardened cutting surfaces, one fixed and one turning, set a precise distance apart. A particle can only leave once it's small enough to fit through the gap, so the size is far more even. For pour-over, a burr grinder is the single biggest upgrade.
Conical vs flat burrs
| Conical burrs | Flat burrs | |
|---|---|---|
| Shape | A cone turning inside a ring | Two parallel rings facing each other |
| Common in | Hand grinders, many home electrics | Higher-end electrics, commercial grinders |
| Typical cup | A bit more body and texture | Often more clarity and separation of flavors |
| Practical | Lower speed, quieter, less heat, compact | Usually larger, motor-driven, can retain more grounds |
These are tendencies, not laws. The burr's geometry, how well it's machined, and how precisely the burrs are aligned matter more than the shape family. A well-made conical grinder beats a poorly aligned flat one every time.
Burr materials
- Stainless or hardened steel: the standard. Sharp and durable.
- Coated steel (titanium nitride, DLC and similar): stays sharp longer. Mostly marketing on home grinders, but harmless.
- Ceramic: found in many budget hand grinders. Holds an edge well but is brittle, and tends to grind less precisely.
Hand vs electric
Hand grinders give you the most grind quality for the money, because you're the motor. They're quiet, portable, and easy to clean. A single cup takes roughly 30–60 seconds of cranking, and light roasts take more effort than dark.
Electric grinders are about convenience: no effort, quick for big batches. To match a good hand grinder's quality, expect to spend more.
Features worth caring about
- Stable burrs. In hand grinders, a shaft supported by two bearings keeps the burr from wobbling, so particle size stays consistent.
- Fine-enough adjustment. Clicks small enough to make modest changes, or stepless adjustment.
- Low retention. Little coffee left inside, so your dose is accurate and you're not brewing yesterday's grounds.
- Range. Cheaper grinders often struggle at the very fine (espresso) or very coarse (cold brew) ends. For pour-over, the middle is what counts.
Choosing a grind size
| Size | Texture | Used for |
|---|---|---|
| Extra fine | Flour | Turkish coffee |
| Fine | Fine sand | Espresso, moka pot |
| Medium-fine | Table salt | V60 and cone drippers |
| Medium | Coarse sand | Flat-bottom drippers, batch brewers, Chemex (medium to medium-coarse) |
| Coarse | Sea salt | French press, cold brew |
Grinder settings aren't universal: "20 clicks" on one grinder is nothing like 20 on another. Start in the medium-fine range, brew, and adjust from taste and brew time. The grind size guide walks through exactly what to change when a cup tastes sour, bitter, weak or muddy.
As a rule, grind finer for lighter roasts and smaller doses, and coarser for darker roasts and larger batches.
Looking after your grinder
- Brush it out every week or two. Old coffee oils go rancid and can taint fresh beans.
- Don't run water through it. Wet steel burrs rust. If your burrs come out for cleaning, dry them completely.
- Skip the rice trick. Grinding rice to "clean" a grinder can strain the motor and leave starch behind. Use a brush, or grinder-cleaning pellets the manufacturer approves.
- Static and mess: a single drop of water stirred into the beans before grinding cuts down on chaff clinging to everything. This is sometimes called RDT.