Burr grinders work by forcing coffee beans between two grooved surfaces called burrs. They come in two shapes, flat and conical.
Unlike blade grinders, burrs produce a consistent grind over a wide range of sizes—this result in better coffee.
There are a few big differences between flat burrs and conical burrs—and lots of small ones—but you can make delicious coffee with both. But since coffee grinders are a big purchase, it’s worth considering the details.
This is where conical and flat burrs are fundamentally different. Both flat burr and conical burr grinders use spiral grooves to force coffee between the burrs. But the force of the grooves isn’t enough alone.
Conical burrs are shaped to allow gravity to assist the beans through the burrs, while flat burrs use centrifugal force to push the beans outwards between the burrs. This means flat burrs need to spin much faster than conical burrs, at least 700rpm—much faster than you can turn by hand.
There's no such thing as a hand ground flat burr grinder, only electric. (maybe steam powered?)
All grinders need to be adjusted for taste. There are real differences in the grounds from flat and conical burrs, but they don’t matter once you’ve adjusted the grinder and other variables in your brew method.
Both flat and conical burr grinders produce high quality grounds and are used in serious speciality cafes and to win competitions.
Heat isn’t a problem if you only make a few coffees at home. But, in a busy cafe where you run the grinder all day, excess heat can be an issue. The hotter the grinder, the less consistent the grind. This leads to more sour and bitter coffee.
Some research has shown freezing coffee beans before grinding them leads to a more consistent grounds.1
Flat burrs retain more wastage than conical burrs, increasing the chance of contaminating a future grind. How much more wastage?—it really depends on the model. Some grinders are especially designed to retain zero waste.
Flat burr grinders require more powerful motors and so are generally louder. How much louder depends on the model. Unless you have specific reasons for avoiding noise, this shouldn’t factor into your decision.
Electric conical burr grinders are a little less expensive than flat burrs. This is because they don’t require as powerful motors. But, again, there’s no such thing as a handground flat burr grinder—so you can always get a good hand grinder for less money.
The most important features of conical and flat burrs are the same; they can both produce high quality coffee grounds. So, unless there’s a specific reason you need to use a flat burr, we recommend using conical burrs.
Conical burr grinders on average are quieter, cheaper, and produce less waste and heat. They’re also more popular, making troubleshooting easier and giving you a wider range of choices.
Modified — Tuesday, 28 May 2019
Published — Tuesday, 28 May 2019