There are a lot of steps that go into making great coffee; in addition to how and where the coffee beans are grown and the expertise of the roastmaster (ours has been roasting coffee beans in East Texas for over 25 years!) the brewing process itself is essential in making or breaking a truly great cup. And the size and consistency of your grind plays a big part in that.
So, what’s the ideal grind size? That depends on how you’re planning to extract all that delicious coffee flavor: are you using a pour-over cone brewer? An automatic drip machine? An Aeropress? Different coffee makers work different ways—a French press, for example, has a fairly long brewing time: you let the grounds sit in the water for around 4 minutes. But if you’re pulling a shot of espresso the water will come in contact with the grounds for less than 30 seconds.
A quick rule of thumb for grind size is this: the shorter the brewing (extraction) time, the finer the grind. So, the aforementioned French press requires a coarse grind, the espresso machine uses a fine, powdery grind and your typical drip machine is somewhere in the middle.
If you used a fine grind in your French press too much of the coffee’s surface area would come in contact with the water for too long a time; after extracting all the good flavor out of your beans it would just keep on going until it sucked out all the bad flavor, too. Over-extracted coffee tastes bitter, harsh and mean, so avoid it at all costs! Conversely, using coarse grinds in an espresso machine will net you a very bad cup of hot water.
Here’s a chart!
|Coffee brewing method||Ideal grind size||What it looks like|
|Espresso machine||Fine/espresso grind||Confectioner’s sugar|
|Drip coffee makers with cone-shaped filters and moka pots||Medium fine grind||Granulated sugar|
|Drip coffee makers with flat-bottomed filters and Aeropresses (depending on the method you use)||Medium grind||Beach sand|
|French presses, percolators and plunge-style brewers||Coarse grind||Kosher salt|
|Toddy cold brewer||Extra coarse grind||Big chunks|
We can’t really talk about coffee grinds without talking about grinders! While it’s easy and convenient to buy your coffee pre-ground, you’ll lock in a little more freshness if you wait to grind it yourself right before you start brewing. This will also give you more control over the taste—if your particular brewing method is producing java just a bit too bitter or a bit too weak, try adjusting the grind size up or down until you hit that magical sweet spot. The chart above reflects the industry standard and is a great starting point, but in the end personal taste trumps all.
It follows that, if the size of your grind has so much effect on flavor, the consistency of that grind is just as important. Grounds that are half perfectly-extracted and half over-extracted aren’t going to taste half great and half okay—just okay. This is where the quality of your grinder comes into play.
A quick rule of thumb for grinders is this: blade grinders are cheaper and grind inconsistently; burr grinders are more expensive and do a better job. Blade grinders use a propeller-style blade to chop up the beans, similar to a blender; the amount of time the blades are spinning determines how fine most of the coffee will be (you’ll get better results if you pulse it and give it a couple of shakes between pulses, instead of grinding it all in one go.) Burr grinders crush a few beans at a time between two abrasive surfaces that have been set a certain width apart, allowing only correctly-sized grounds to pass through.
Making good coffee is an art but also a science, so get yourself a grinder and start experimenting!