If you love brewing your own coffee, you know that grinding beans yourself is an important step to ensuring a perfect cup. But even more important than that is to ensure that your coffee is ground evenly. Uniformly sized grounds are critical to making superb coffee.
Sadly, even the fanciest burr coffee grinders can yield a mix of particle sizes. That unevenness corrupts the ideal flavor of your brew, ultimately hindering its potential taste.
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But don’t lose heart. In this guide, I offer a simple way to test and calibrate your home coffee grinder so that it’ll perform at its peak.
And if you suspect your old workhorse isn’t grinding like it used to, you’re in luck. These steps will confirm that too.
Even fancy burr coffee grinders create grounds of mixed particle sizes.
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Why grind uniformity matters
Uniform grind size may sound like yet another thing for coffee nerds to obsess over. If you love good joe though, it’s no trivial matter.
Let’s assume you have an excellent coffee maker, plus freshly roasted whole coffee beans. Now pair this with a mediocre grinder. The drinks you brew might not be bad. They may even be pretty good. But to coax the ultimate flavor from your beans, you’ll need to do better.
The reason boils down to surface area. Finer grounds have more, bigger bits have less. So, water extracts coffee compounds from fine grounds faster than coarse grounds.
This leads to uneven extraction. Fine, overextracted grounds add bitterness to brewed coffee. Large, underextracted grounds bring weak flavor and sourness to the party.
The Kruve Sifter will help you find out how well your grinder processes coffee beans.
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Step 1: Gather your tools
You’ll need two tools for this project. The first is an ordinary kitchen scale. You may already own one. Typically about $20, they’re relatively cheap though if you don’t.
The second item, the $49 Kruve Sifter Two, consists of two stainless-steel mesh sieves, along with three internal compartments. It’s the base model designed for pour-over brewing. Yes, that’s a pretty specific tool, but you’ll see why.
Make sure you have some whole coffee beans on hand as well. Lastly, keep your coffee grinder in reach since you’ll be putting it to use.
Start at a coarse setting, then work your way toward finer grind sizes.
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Step 2: Weigh and grind
First weigh out 10 grams of coffee beans. Next, set your coffee grinder’s coarseness level. Start with the coarsest setting that’s still within the recommended range for your brewing method.
In my case I used the Baratza Encore ($139 at Amazon), set at 15 (0 to 40). At this point it’s a good idea to record the weight of each of the Kruve’s sections (including the screens but not the lid). It’ll make life easier later.
Now, grind the coffee and drop it into the Kruve’s top section.
Drop your grounds into the top of the Kruve Sifter.
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Step 3: Sift the grounds
The next step is to sift your grounds. With the ground coffee inside the Kruve, replace its lid. Shake the device back and forth horizontally for 60 to 75 seconds.
Be sure to tap the Kruve’s sides periodically during the process. This helps to dislodge any coffee grounds that might cling to its interior compartment walls.
At the right setting, your grinder will create grounds that stay in the Kruve’s middle section.
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Step 4: Analyze the product
Carefully place the Kruve on a flat surface, remove the lid, then separate its compartments. You should see that the Kruve has sorted your grounds into three sizes. Coarse grounds will be in the top section, midsize grounds will be in the middle and fine particles will have landed at the bottom.
What separates the grounds are the two screens that differ in porosity. Small particles pass through the first screen (800 microns). Grounds that are smaller still move though the second (400 microns). Ideally you want to have most of your grounds land in the middle chamber.
If your grinder is set to the correct coarseness, most of your grounds will be in the middle chamber, and you’ll have a small, equal amounts of fine and coarse grounds.
Confirm by weighing each Kruve chamber (still containing sieve and grounds). Subtract from each value the weight of the empty chamber (which you recorded earlier). That’ll give you accurate amounts without the hassle of transferring ground coffee to another container.
Step 5: Adjust and repeat
It’s likely that you’ll get wonky results on your first attempt. For instance, you might have more coarse grounds than medium or fine. Or you may have too many finely ground bits of coffee and not enough medium. In that case, dial your grinder a few levels toward finer grind. Then repeat the process until you’re successful.
You might encounter an issue where your grinder produces unbalanced size ratios no matter what its setting. If so, then you probably have a bigger problem — worn-out burrs. In this case, you’ll likely have to purchase new burrs from your grinder’s manufacturer. Another option is to send your machine to the factory for repair. And if all else fails, you can always go shopping for a brand-new one.