Burr geometry plays a significant role in shaping the taste of coffee. Burr shape affects the mix of particle sizes a grinder produces, which changes extraction—and what you taste. While there are many burr designs, one fundamental choice is whether you’re using flat or conical burrs.
Mechanically, flat burrs are two rings facing each other: beans feed in near the centre and are pushed outward as they’re ground. Conical burrs are a cone inside a ring: beans feed down through the burrs as they’re crushed to size.
You’ll often hear this summed up as: flats lean toward clarity and separation, while conicals lean toward body and sweetness. That holds true in many setups, though burr design, alignment, RPM, and burr condition can shift the result—so treat it as a strong tendency rather than a guarantee.
Quick comparison (at a glance):
| Category | Flat burrs (typical tendencies) | Conical burrs (typical tendencies) |
|---|---|---|
| Taste profile | Often described as clearer, with more separated flavours | Often described as rounder, with more body and sweetness |
| Mouthfeel | Often perceived as cleaner/lighter | Often perceived as heavier/syrupier |
| Dial-in feel | Can feel more revealing and responsive to small changes | Can feel more forgiving day-to-day |
| Often favoured by | People chasing clarity and distinct flavour notes (filter, lighter roasts, modern espresso) | People who prefer fuller-bodied espresso and milk-based drinks |
In the cup, flat burrs are often described as tasting cleaner and more defined—one reason they’re popular for lighter roasts and filter brewing, where you want distinct notes to stand apart. In espresso, flats can come across as more “structured” (layered rather than blended), especially when you’re aiming for clarity-forward shots.
With conicals, espresso often feels rounder, sweeter, and has more weight. Many people like that for milk drinks, because a thicker, fuller shot can cut through milk more easily. If you love that style but still want a flat burr grinder, you can often move the flavour in that direction by choosing a slightly more developed roast, pushing a touch longer yield, or dialing for a bit more sweetness and body. (In other words: burr shape influences the result, but it doesn’t lock you into one flavour forever.)
Workflow matters too: retention, mess, and how easy it is to switch beans. These are mostly grinder-design choices rather than burr-shape choices, but many modern single-dose grinders are built specifically for low retention and quick bean swaps—great if you rotate coffees or brew both espresso and filter.
Which should you choose? Start with what matters most. If you’re chasing clarity and distinct flavour notes (especially in filter or lighter roasts), flat burrs are usually the better bet. If your priority is body, sweetness, and a more forgiving espresso—particularly for milk drinks—conicals often deliver that style.
For most home brewers looking for flexibility across espresso and filter, flat burr single-dose grinders are an excellent default.
If you’re shopping for a flat burr single-dose grinder, our two core options are the DF54 and DF64 Gen 2. For help choosing between them, see our DF54 vs DF64 comparison. For common grinder questions (returns, maintenance, warranty), refer to our FAQ.
For more information on single-dose grinders, see our page Single Dose Coffee Grinders — What Are They?