If you want the freshest, most full-flavored cup of coffee, we always recommend grinding your own coffee beans. It’s best to do this right before you brew, as our testing has shown that the beans begin to lose flavor and aroma within an hour of being ground.
Home coffee grinders come in two styles: blade and burr. A blade grinder works like a tiny food processor, with a rapidly spinning blade that chops coffee into smaller and smaller fragments. You have to hold the grind button down, time the grind, shake the grinder periodically to distribute the beans, and visually inspect the coffee to see if it’s reached the desired consistency.
A burr grinder, by contrast, operates like a pepper mill—it forces each bean to pass through a gap of a particular size. While a blade grinder has one chamber where you load, grind, and dispense the beans, a burr grinder consists of three components: a hopper where you feed in the beans, the grinding chamber, and a removable container that holds the grounds so you can transfer them to the coffee maker. You simply switch the machine on and whole beans are pulled from the hopper through two gear-like metal rings (called burrs) that spin against one another to crush the coffee. The setting you choose on the machine determines the space between the burrs and thus the size of the grind. Since each bean passes through the burrs and gets crushed only once, it’s a more precise process than using a blade grinder.
Burr grinders are the gold standard in the coffee industry, but now household brands such as Breville, Hamilton Beach, and KitchenAid are offering them for home users. To find out more about this popular grinding method, we tested 10 models priced from $29.86 to $199.99, all with metal burrs and at least eight grind settings, and compared them to our favorite blade grinder from Krups ($17.99).
Brew method usually dictates grind setting: Generally, coarse coffee is used for French press, medium for drip machines, and fine for espresso. A good grinder should be able to produce these three consistencies, so we ground coffee on the settings recommended by each manufacturer for coarse, medium, and fine. We repeated the grinding tests with light roasted beans and very dark roasted beans, which have different densities. Finally, we had six testers—from novices to coffee experts—operate each grinder to gauge its user-friendliness.
All the grinders were able to grind the coffee, and there were no stalled or burnt-out motors. But many of the machines were confusing or a pain to use. Some sprayed grounds all over the counter even when their collection containers were properly in place. Others had displays that were befuddling or hard to read, with hieroglyphic-like symbols that we needed the manual to decode or numbers that were visible only when we looked at the machine from certain angles. We also disliked products with grounds containers that were too small or irregularly shaped—small containers overfilled easily when we tried grinding for a crowd, and oddly shaped vessels poured imprecisely when we transferred the grounds to the brewer.
Some of the grinders fell short in other ways. One innovative grinder had a built-in scale that promised to dispense the exact desired amount of beans. However, when we weighed the ground coffee on our lab-calibrated scale, we found that the grinder missed the target weight by 10 percent every time, even after we reset its internal scale. A second copy of this model was inaccurate by 6 percent. Another grinder shook heavily as it ground, rattling the table and changing its grind setting. Finally, one grinder’s glass grounds container shattered when we accidentally elbowed it off the counter. We don’t expect our small appliances to be bulletproof, but we’d hope our coffee grinder could survive groggy morning mishaps.
Our favorite grinders were intuitive and easy to use; had roomy, sturdy plastic grounds containers that could withstand a morning drop; and ground cleanly without making messes of our kitchens.
Next, we zeroed in on the evenness of the ground coffee, one of the much-touted benefits of burr grinders. Scott Frost, postdoctoral scholar at the UC Davis Coffee Center, told us that brewing coffee is inherently a race against time. Coffee has more than 800 aromatic compounds, and the goal is to try to extract as many of the pleasant aromatics before some of the more unpleasant flavors—such as excessive acidity or bitterness—have time to dissolve into your brew. If all the grounds in your coffee were the exact same size, this would be relatively easy because the water would extract each tiny piece of coffee at the same rate. But ground coffee is never completely even.
Coffee beans shatter like glass when they’re ground—they break into some big pieces, some medium pieces, and some tiny dust-like pieces. In the coffee industry, those big pieces are referred to as “boulders” and the dust-like pieces are called “fines.” In a typical brew, the boulders will be underextracted (tasting dull and flavorless) and fines will be overextracted (tasting bitter and acidic). Some amount of boulders and fines is inevitable no matter how great your grinder, but burr grinders are known throughout the coffee industry for producing an exceptionally even grind (a high percentage of medium pieces) compared to blade grinders. In theory, a more even grind means more control over your final brew.
To get a read on evenness, we ground coffee and sifted it in the Kruve Sifter, a device used by coffee professionals that separates the large pieces, medium pieces, and dust-like particles. We repeated this test, tweaking the grind settings until we achieved the maximum percentage of medium pieces. The grinders in our lineup produced grounds ranging from 28 percent to 88 percent medium pieces, with highly ranked models at the top of that range.
To figure out what was causing the unevenness in lower-ranked models, we took apart the grinders to look at the shape and construction of the burrs. All the burrs were made from metal, but they varied in shape. Burrs are typically either conical or flat. Experts told us that a good burr, regardless of shape, has sharp, deep, uniform grooves all along the grinding surface and fits into the grinder very rigidly. A very dull burr is akin to cutting with a dull knife—it makes the pieces ragged and uneven—and a burr that wiggles a lot can create pockets that allow bigger coffee pieces to slip through without being fully ground.
The three poorest-performing grinders in our lineup were all priced less than $50.00, and their construction was notably flimsy. The burrs shook and rattled as they ground—the burr on one model occasionally popped up and out of place during grinding. On closer inspection, we noticed that all three grinders featured identical-looking burrs, with protruding screw heads, indentations, and shallow, short grooves—an uneven grinding surface that leads to inconsistent grounds. An engineer who helped us dissect the grinders pointed out that the protruding screw heads were probably doing most of the grinding and essentially whacking the beans over and over like a blade grinder instead of crushing them effectively like our best burr grinders. The burrs on our favorite grinders had sharp, deep grooves that made quick work of pulverizing the beans and consistent surfaces that provided supereven grinding.
But how much does grind evenness really affect your cup of coffee? To find out, we brewed three batches of coffee using the same beans ground in the most even burr grinder, the least even burr grinder, and our top-rated blade grinder, which achieved up to 46 percent medium pieces. We kept all the variables the same except for the grinder. A panel of 21 tasters then sampled the coffees in a blind tasting.
The verdict was surprising: Though we identified flavor differences in the batches of coffee, each made a good cup and tasters were split on which one they preferred. To verify these surprising results, we conducted this test three additional times. We also brought in coffee tasting experts, and they came to the same conclusion.
So if the evenness of your grind doesn’t matter all that much, why is the coffee industry so excited about burr grinders? With their range of settings and streamlined designs, which require the beans to pass through the grinder only once, burr grinders can guarantee consistency day after day in a way that blade grinders can’t. Ultimately, we think a good burr grinder is best for home brewing, too, since these machines are easy to use and take the guesswork out of grinding. And even though grind evenness isn’t the most important factor in how your coffee tastes, we also gave an edge to grinders that were more even, since they left no whole or partially processed beans in our grind (a waste of good coffee).
We found several burr grinders we liked, with the Baratza Encore ($139.00) leading the pack. The darling of the coffee industry, this machine produces a very even grind, but we particularly appreciated its simple design and no-fuss grinding: Choose your grind setting, add your beans, and you’re done. We also liked that it has 40 grind settings, giving coffee aficionados the ability to customize their cups. Our Best Buy, the Capresso Infinity Conical Burr Grinder ($99.99) is also intuitive, but it has just 16 settings and doesn’t work well when grinding coffee for a single cup. Either of these machines will round out your set of coffee tools and elevate your brew.
A final note: No matter which grinder you choose, be prepared for a small learning curve. Experts told us that different types and roasts of coffee will all grind a bit differently, so take time to get to know your grinder and tinker with the settings until you find what works best for you.