We put them to the test
Coffee obsessives care a lot about grinders. If you're investing in good coffee beans, the mechanism that you're using to render them into grounds plays a big role. But I'll be honest, I never really thought it made that much of a difference whether you went for a blade grinder or a burr grinder. So I decided to test them side by side, in a French press, a pour-over, and a Moka pot.
There's a pretty big difference between a blade and a burr grinder. Blade grinders have rotating blades, like a blender, that slice up the beans into grounds. For this test, I used a Krups Electric Coffee Grinder. Burr grinders are more precise pieces of equipment. Two burrs, either conical or flat, slowly grind the beans into even pieces. You can use a manual one that has a hand crank, or you can invest in an electric one that lets you choose a setting, from coarse to fine. For this test, I used the Krups Adjustable Burr Grinder, an electric model. It runs $49.99, while the blade grinder retails for $19.99 (though you can often find it cheaper). The question at hand was: Can I, someone who drinks coffee pretty much every day but definitely doesn't consider myself to be all that picky, tell a difference in which makes a better cup?
For a French Press
First up, I tried both grinders with my trusty Bodum French Press, which is what I use most mornings to make a cup of coffee before I fly out the door for my morning commute. In each grinder, I ground about a fourth of a cup of beans from Intelligentsia's Gesha Village Ethiopia, a very delicious coffee that is much nicer than what I would probably buy for myself. I adjusted the burr grinder to the second-coarsest setting and pulsed the blade grinder until the contents looked fairly coaresly ground. In the two cups of coffee I made, the taste was pretty similar, but it was clear that the burr grinder had done a better job of pulverizing the beans evenly. In the burr grinder cup, there were fewer of the flecks that sometimes float up to distrub your morning coffee drinking. But the difference was slight—if I hadn't been looking for it I might not have noticed.
For a Pour-Over
For the second round, I used my Melitta Ceramic Pour-Over. I tried a Chemex-style one, but I kind of hated it? This one makes pour-overs less intimating, plus it has a cute little pot. The only disadvantage was I consistently overestimated how much liquid it could hold, so I often ended up with a small surrounding coffee puddle. Again, I ground about a fourth of a cup of beans, this time on a middle setting, and attempted to approximate a finer grind with the blade. In this round, the taste of the beans was clearly better with the burr grinder. The blade was hard to finagle into anything in between a pebbly coarse grind and absolutely pummeled to death into powder, so it made sense. The burr grinder made a better cup, if only because I didn't have to approximate—you just put the setting to what you wanted and let 'er rip. Can you do just fine with a pour-over and a blade grinder? Definitely. But this format definitely rewards a burr grinder more than a French press.
For a Moka Pot
The clearest difference, though, was definitely in my 6-cup Bialetti Moka pot that lives on the stove. (Yes, I own a lot of different gadgets that make coffee. I work at a breakfast site.) This time I opted for Starbucks Espresso Beans because that's what I had on hand—don't hate the player, hate the game (capitalism). I set the burr grinder to the second finest setting and pulsed the blade grinder for a lot longer than I normally would for a French press, to try to approximate the finer setting. The burr grinder did a much better job here, making the grinds consistently even and prevently the dreaded layer of slurry that can sometimes collect at the bottom of your cup. The blade grider produced much more uneven results. Some of the grounds were too fine, which meant they weren't effectively filtered out, and some were clearly too coarse no matter how much I pulsed.
What's the verdict?
Is a burr grinder worth it? If you like buying whole beans, and you prefer a pour-over or a Moka pot, yes, definitely. If you like using a French Press, I'd say not really. Either option is definitely better than trying to grind your beans in a blender after you realized your grinder broke which I, uh, have definitely never done.