So, there’s two main types of coffee grinders. The Blades and The Burrs. A blade grinder uses propeller style blades to ginsu chop the beans into bits. A burr grinder uses two sharped grooved discs that pummel and grind the beans into a fine, even pulp.
Now, we’re not gonna tell you that the only way to make a good cup of coffee is to go out spend a whack of money on some fancy ass burr grinder. That’s just not true. If you’re just getting into the game, and want to keep your costs down, grab a cheap spice grinder from Walmart and get busy. You can work up from there.
But in the interest of covering all the bases, here’s the real deal when it comes to the differences between the $10 Walmart spice grinder, and the $300 burr grinder from that pretentious coffee shop in the strip mall up the street.
Essentially, blade grinders chop up the beans into boulders and fines. Boulders are the larger chunks that didn’t get the full ginsu treatment. And the fines are the nice powdery ground up bits that spend lotsa time on the blade. The boulders will have less flavour. The fines will have more falvour. The result will be a bit of a mix of the two. The other pitfall to the blade grinder is that it gets really, really hot from friction and speed. And sometimes too much heat during grinding can change the flavour of the coffee.
Burr grinders, on the other hand, will grind the beans evenly, crushing them in between the grooved discs at a low speed. This low speed will generate less heat than the blade grinder so there will be no effect on the flavour. But there will be no boulders and no fines. Just one uniform grind. (Note: this uniformity is especially important if you’re making espresso).