On the spectrum of things coffee enthusiasts argue over, the type of burr used in a given grinder (and how it affects the eventual coffee itself) is a topic usually reserved for the most granular, minutia-prone scholarly types.
If you are impatient to read this post, you can check our list of best burr grinders.
Before going any deeper into this subject, it’s important that we state up-front that if you are simply someone who enjoys having a quality daily cup of coffee to get you going, you may not even be able to tell a difference between two different types of burrs, and that is perfectly okay.
That said, if you are a budding coffee scientist bent on exploring the most intricate details of the art of the brew, this will be a post for you.
What’s the Difference?
A flat burr grinder is literally flat, whereas a conical burr is going to have some verticality to it. To give you a visual aid, here is what the two types of grinder burrs look like:
So, now that we know what the physical differences between the two are, what practical effect do they have on your actual coffee? Let’s find out.
Let’s get one thing straight right away; neither a flat nor a conical burr will produce coffee grounds that are inherently better than the other. A high-quality version of either type is going to give you excellent results, so that’s not what we’re really comparing here. Instead, we’re looking at what each would be potentially best-suited for, and this is where differences start to make themselves known.
For instance, a flat burr will produce a grind that is extremely consistent in terms of the individual size of the ground coffee particles.
By contrast, a conical burr is going to produce two distinct sizes; a smaller, fine grain, and a larger one.
In terms of making conventional espresso, these dual-size particles are very useful. The smaller ones trap water, restricting its flow through the grounds as a whole and helping the larger ones become fully saturated.
That said, a flat burr allows for much more experimentation with the end product; a fact that many baristas and coffee shops around the world are beginning to embrace.
Though this is admittedly a minor consideration amongst minor considerations, a flat bur grinder is going to produce more waste than a conical one. This is due to the fact that unlike the latter, the flat shape of the former tends to trap some of the grounds inside. This also makes cleaning a bit more tedious.
Because they are gravity-fed, conical burr grinders do not require as much power to operate, resulting in a lower noise output than flat burr-based units. This isn’t going to be a night and day difference, mind you, but it will still be noticeable if you listen for it.
As with noise, a conical burr is going to produce less heat due to the lack of excessive friction involved in the grinding process. This is most applicable when making bulk amounts of coffee. But, the additional heat from a flat burr grinder can produce more heat damage to the grounds, resulting in a slightly altered flavor profile.
Canonical or Flat: Which Burr Grinder is Better?
Overall, as we’ve hopefully made clear above, there is no true winner when it comes to the debate between flat and conical burrs.
Many may prefer the conical for its ability to produce grounds suited for traditional espresso, but outside of this, it isn’t very conducive to experimentation. Because of that, others may lean towards the flat burr style.
Which one should you choose? Well, if you’ve made it this far and you still aren’t sure which you prefer, our best advice would be to try them both and experience the differences for yourself.
Anthony is a professional barista in the city of Chicago. He has written for many online publications on various topics related to coffee.