ROK Grinder

I remember when I got my first burr grinder, it was a small stainless steel hand crank outfitted with two ceramic burrs. I was excited to take my coffee game up a notch, but my friends and family weren’t too convinced. “Grinding your beans by hand?”, they asked suspiciously as I turned that crank one revolution at a time until I had enough grounds to start brewing. I was able to brush off the looks and comments with ease because I knew something my doubtful onlookers didn’t - a consistent grind particle size was an imperative step to brewing the perfect cup.

Since then I’ve used all sorts of grinders from manual mills to automatic machines, from conical ceramic to flat steel burrs. Just recently I had the opportunity to test one of the new kids on the block, the ROK Grinder.

When you first take the ROK Grinder out of the box, it’s build quality is immediately apparent. Built of die cast aluminum, the weight and sturdiness of this grinder suggest quality components that have been crafted with care. The ROK Grinder boasts 48mm hardened steel conical burrs and an ingenious gear system that is made from Acetal - an engineering plastic that possesses qualities of both metal and plastic.

Assembly is quite simple, as attaching the crank arm is the only setup required. Once it was put together and at home on the countertop, is was time to put it to the test. I dosed 20g of coffee, loaded it in the hopper, and began to crank.

Burr grinders differ from blade grinders by crushing the beans as opposed to slicing and chopping them, resulting in a much more uniform particle size. Because the beans are getting crushed between the burrs with each rotation of the crank arm, most manual burr grinders are a literal labour of love. It can be time consuming and even physically laborious to grind beans by hand, but the ROK Grinder does it faster and easier than any manual grinder I’ve ever used. ROK claims that this grinder is twice as efficient as most hand grinders, and although I didn’t count my revolutions I did notice that I was grinding my doses much quicker than any other hand grinder. In about 30 seconds I was able to grind my 20g pour over dose, and did it all without breaking a sweat thanks to the vertical crank motion.

Not only was the grinding motion efficient, it was surprisingly sturdy. Different from most hand grinders, the ROK sits on the countertop instead of being held to grind. On the bottom of the baseplate is a tacky material that helps keep the grinder in its place. With a little stability from your non dominant hand, the grinder stays put on the counter and doesn’t budge. If the tacky material gets a little dirty, it can be easily cleaned with water only to regain its stickiness when it dries.

So the grinder looks great, it feels great, but how does it stack up against other grinders in its price range?

With the help of a Kruve sifter, I was able to analyze particle size in microns to determine just how well this grinder performs. At a grind setting appropriate for a pour over dripper like a Hario V60 or Kalita Wave, I compared particle size between the ROK and my Baratza Encore. Using sieves to filter out boulders and fines, the ROK consistently outperformed my Encore. Less boulders, less fines, and more of my target particle size resulted in a better cup from the ROK every single time. 

The ROK boats a stepless adjustment wheel for infinite micro adjustments, enabling you to dial the grind setting in just right. If you prefer to make stepped adjustments, you can easily reconfigure the washers to get that familiar stepped feel.

So, what’s the verdict? Well, there’s good news and bad news. The bad news is, this grinder isn’t perfect. I noted a pretty significant static charge that caused the grinds to stick to the included dosing cup. The ROK doesn’t have a small footprint, either. It’s similar in size to most automatic grinders in its category, but it’s much bigger and less portable than other hand mills.

The good news is, no grinder is perfect. Manual and automatic grinders in the home brewer’s price range will all have their limitations, but this grinder doesn’t have many. 

If you’re still using that blade grinder that your mom gave you when you moved out and went to college, it’s time for an upgrade. A manual mill is a great entry point to burr grinders, and this one is one of the best. Boasting elegant design, effortless operation, and truly impressive performance, this ROK grinder might just be the grinder for you.