Flat Burrs vs Conical Burrs. That is the question.

by Xavi Guerrero January 21, 2021

In this post, I will give a brief breakdown of flat burrs vs conical burrs in an attempt to put aside the one question that gets asked frequently. Which one is better? Our lineup of grinders offers both options and we have designed it that way to provide alternatives to the multitude of coffee journeys our customers may have.

There’s really not a right or wrong answer, it’s like comparing apples to pears. Very similar but different. We will highlight some of the possible differences and other factors below.

IT’S NOT JUST THE SHAPE OF THE BURRS.

First things first. The main function of a grinder is to force coffee beans through a gap between two burrs that operate with a combination of two processes that crush and cut the beans into particles that you can brew with. At Baratza we have a holistic approach to design high-quality grinders that are practical and reliable from the inside out. We know the burrs are a critical element to how the ground coffee comes out, but they aren’t the only factor in play. There are other systems on the grinder that affect the production of ground coffee, it’s not just the shape of burrs. The power source, the grind adjustment, and the transmission that puts the power on the burrs are also important. 

For example, on the BARATZA Encore, you may notice a difference in your morning cup’s taste and trace it back to the grind. The most common assumption is that you need to replace your burrs, but again, it’s not just the burrs. In cases like this, we might recommend you watch our video on how to troubleshoot a grind quality issue.

TAKING SHAPE

When it comes to burr shapes there are two most common – flat and conical. Flat burr sets have two compatible shapes that lay parallel against each other. Conical burr sets consist of a ring and cone shape that fit in each other. Both sets leave gaps to allow coffee bean ground particles to pass through. That gap is your grind setting.

Essentially, the purpose of grinding coffee is that burrs break and cut down the beans apart so when the water touches those particles flavor may be extracted. To do that, a lot more things are happening in the process and that’s where the differences between flat and conical burr sets start.

RETENTION

The difference in shape may affect how the grounds flow out of the grinder. Although, the overall design of the grinder can affect this too. A common misconception is that flat burrs retain more coffee. Due to their distribution process where ground beans flow out mostly by extrusion, some of it may get caught in the middle. Our flat burr grinders have a dome-like surface in the center of the bottom burr holder that helps push beans and large particles towards the teeth, making sure minimal retention occurs at the center of the burr.

Conical burrs on the other side, use mostly gravity and the auger shape to push out ground beans. Retention will depend more on the design of the grounds chute, but the burr shape may help. The Sette series implements a revolutionary gearbox and burr set design where the outer burr or ring burr spins and allows for straight-through passage of the grounds. The rotating burr also presents far more teeth and surface area to the beans and results in them being actively drawn into the grinding teeth. The results are fast grinding and minimal waste – near zero retention.

GRIND SETTINGS

Another confusing difference when it comes to flat burrs vs conical burrs may be ground settings or range. Because of the layout of cutting edges or size in burr sets, it might be easy to think that flat and conical burr sets have a different range of grind settings. That’s not necessarily true.

The function of the burrs is to break and cut down a bean to let the particles through a set gap. When you adjust the gap, you can define a range of grind sizes. The bigger the gap, the bigger the grind particles it lets through. Sizing may be impacted by the brittleness of roasted coffee so minor adjustments of this gap provide a big difference when it comes to taste. That’s why some of our grinders have micro and macro adjustments for grind settings.

GRIND CONSISTENCY

Speaking of brittle. There are a lot of variables that affect coffee brittleness and how the burrs will effectively break and be cut into a consistent size. Some of them can be bean densities, blends of origins, varietals, and more importantly – roast levels. Darker roasted coffee is more brittle than lighter roast and it will make it more difficult to control a grind distribution. Like a piece of bread, the darker your toast the more crumbs you’ll get when you drop it. 

Flat burr and conical burr sets may each have different advantages depending on their cutting edges and the overall design of the grinder they are paired to. This may also be determined by the brew method and flavor profile you are most comfortable with. Espresso uses water pressure to extract flavor from ground coffee so it benefits from finer particle distribution. French press is an immersion method and needs more coarser pieces so water can extract flavor through prolonged exposure to the coffee ground and not over extract. 

IT COMES DOWN TO TASTE

This is where I burst your bubble and remind you that there’s no solid right or wrong. Taste is the most important factor when it comes to your cup of coffee, and we always recommend you focus on that. I cannot say what tastes best for you. And flat vs conical burrs can’t either. 

There’s a lot of research for how burrs affect taste, the bottom line is the taste difference between flat and conical burr sets is so small it’s hard to notice without taking into consideration all other factors. At Baratza we believe that everyone is on a different coffee journey. That’s why we have both flat burr and conical burr sets in our lineup. Not just that, we have different materials, like steel and ceramic. And cutting-edge geometries like the S1 and S2 burrs for the Sette series or the M3 and M2 burrs in Encore and Virtuoso+.

We have focused on manufacturing high-quality burrs, machined by MK and Etzinger, and paired them with grinder features so that your brewing experience is at its peak grind after grind. Which burrs are better depending on your cup profile preference.

Please check out our choose your grinder page to learn more about our lineup and each of our grinders’ features and benefits.