Over the past 27 months, we’ve worked on developing a powerful and precise home grinder. Ode Brew Grinder’s 64mm stainless steel flat burrs reduce grind time and heat generation while increasing grind particle consistency. Although we’re still in the midst of manufacturing, we’re excited about our grinder’s early performance data—both qualitative and quantitative.

For qualitative testing, we’ve run a series of sensory tests with leading industry experts—brewing coffee ground by Ode and grading it against other leading café and home grinders. Feedback on Ode’s performance from those sensory tests have been summed up on our Kickstarter page as well as at the bottom of this post so make sure you check it out!

But now for the juicy coffee nerd stuff—the quantitative data. We’ve done a ton of work asking what metrics matter the most to our users, and the first dataset we wanted to release is Ode’s grind profile at two grind settings.

Here’s our preliminary research on Ode’s grind profile, and what it means for your morning cup of coffee.

What Is A Grind Profile?
First off, let’s cover what a grind profile is and how data is collected. Every time a coffee bean is ground, it produces a few big chunks (boulders), a bunch of grinds that are about the size that you want (the target grind size), and some amount of tiny dust (fines). 

“Much like when you cut crusty bread, when you shatter coffee beans there are always going to be some small particles,” explains coffee writer and researcher Scott Rao. “There are going to be dusty little particles we call fines, and there’s going to be some larger particles we call boulders, and a whole bunch of particles in the middle that are going to be the size you want.” (Excerpt from Wirecutter)

Boulders resemble coarse sea salt in size, and for coffee brewing, are generally regarded as being bigger than 1700 micron (μm) across. Fines resemble powdered sugar in size and are less than 300 μm across. Every grinder produces a range of particle sizes, and the way this range is distributed is called a grind profile.

Fines, Boulders, and Target Coffee Grind Size Infographic

The grind profile of coffee determines the flavor of the resulting brewed coffee. The flavor of coffee comes from soluble compounds contained inside coffee grinds that extract and dissolve into water while brewing. Each particle extracts at a different rate depending on its size. The bigger the coffee grind, the less surface area it has relative to its volume and the longer it will take those yummy solubles to extract. For smaller particles, the opposite is true. The good stuff extracts quickly, however the particles can continue to extract and turn into bitter and sour flavors. Brewing coffee is a balancing act of managing these two extremes, and the grind profile of your coffee determines this relationship.

How To Read A Grind Profile Graph
A grind profile can be measured in a variety of ways. For this article, we will focus on grind data measured by a Beckman Coulter LS Particle Size Analyzer. This is a device that shines a laser through coffee grinds and measures the diffraction. Diffraction is when a wave (in this case light waves) bends around the corners of an obstacle or through an aperture (opening).


Diffraction of coffee grinds particles
The Beckman Analyzer uses diffraction to count the percentage of coffee particles of different diameters. To oversimplify, it is counting the percentage of fines, target grinds, and boulders in your coffee. This data is then graphed on a grind profile graph such as the one below.



Coffee grinds profile target grind size chart



The X axis is a measurement of the diameter of a coffee particle. The Y axis shows the percentage of particles of each size that make up the grinds sample. Particles towards the left of the graph are smaller in size and get bigger as you look to the right. The peak of the grind profile will be centered around the setting of the grinder.

Coffee grinds profile target grind size comparison chart

The example graph above shows how different grinders can produce different grind profiles. 

  • Grinder A has two humps which is called bi-modal distribution. It has produced fines below 500 micron (μm), a peak right around 1000 micron, and a drop off with some boulders. 
  • Grinder B has a relatively small hump of fines and a steep drop off after its peak. This would be considered the “best performing grinder” as a large percentage of the grinds are in the target peak/particle diameter.
  • Grinder C has a small hump of fines just under 500 micron, a peak right around 1,000 micron, and a small hump of boulders around 1,500 micron.


Ode Preliminary Grind Profile Results

So how does all this grind profile talk loop back to Ode Brew Grinder? People want to brew great-tasting coffee, which in turn means they want a grinds profile that displays a tall peak with few fines at any grind setting. Although we don’t have the data for all of our grind settings just yet, and this test was performed on our “T0” sample (a very early off-tool manufacturing sample with tons of room for improvement), we’re incredibly happy with Ode’s preliminary results.
Ode Brew Grinds grinds profile data

As you can see from the graph above, Ode produces a consistent grind profile with a tall peak and only a small percentage of fines at both its setting 1, Ode’s finest setting, and at setting 3.3, a medium-fine setting. Also, it’s worth noting that the standard deviation remains, for the most part, consistent and the only change is a nice shift in the mean. Based on qualitative feedback, this has made dialing in Ode an easy endeavor. 

To give you some context on these setting sizes, the Fellow team has been using setting 1 for AeroPress® Coffee Maker (and recipes for our Prismo attachment for immersion), and setting 3.3 for finer pour-over brews such as the Hario V60. We had an issue with our third party lab’s Beckman Analyzer accuracy at coarser settings, so that’s why this blog post is focusing on fine and medium-fine settings. We have very high standards for everything we share with our customers, so we wanted to start by sharing the data points that we were most confident in.

Since taking these samples, we’ve pushed forward with manufacturing, tightening up Ode’s consistency and overall performance. We are running new data on a full range of grinds samples, from 1-11, with our DVT pre-production grinders that will represent the performance of the final grinder you will receive. We expect to release data on the most recent manufacturing samples with a full range of grind settings in the next two months.

From qualitative sensory testing, we’ve also received exciting feedback! Coffee professionals and competitors have been using Ode to make some stunning cups of coffee at this grind setting. They noted complex flavors with high intensity, well-developed acidity, and lingering aftertaste.

“I have tested many home grinders and commercial grinders over the years. Rarely do you see design and function work hand-in-hand with such ease. Most home coffee grinders (and commercial coffee grinders) are obtrusive, overdesigned, and overly arduous. Fellow has succeeded in creating a beautiful and elegant grinder for your home (or café) that is uncomplicated, near-effortless to dial in, and (most importantly from my perspective) produces exceptional coffees, possibly transcendental…” - Benjamin C. Brewer, Director of Quality/Green Coffee Sourcing, Blue Bottle Coffee

You might be wondering, “Hey, if Fellow has an Ode that can already produce a grind profile graph, why do we have to wait until this summer to get our hands on one?” We want to reiterate the grind graphs from Ode shared in this article were produced by our first off-tool sample, or “T0.” This grinder is fully functional and has similar grinding performance as the final grinders we will be shipping to backers. However, there is still a lot more work to do to get the product ready for mass production. We are running through several stages of pre-production builds to consistently get our look, feel, reliability testing, and safety certifications fully dialed in. We want the grinders that will be shipped to our backers to be perfect, so our engineering and factory teams are working around the clock to perfect the process and get Ode into production.

We look forward to getting Ode Brew Grinder into your hands, and sincerely hope you love it as much as we enjoyed designing it!

Authors: 
Hanna McPhee

Jeremy Kuempel
Jake Miller
Hannah Miller