We’d love for you and your ROK to enjoy a long and happy life together. To that end, you’ll find safety and maintenance tips below which will ensure the longevity of your ROK.
Don’t grind your coffee too fine
Using overly fine coffee can lead to damage and breakage of the internal plastic components, and in extreme cases, breakage of one or both levers.
Do not apply excessive force to your ROK. It is not necessary to apply great force to produce great shots of espresso.
We recommend starting with a coarser grind and experiment and gradually moving to a finer grind. For more on how to determine the proper fineness, please check out this blog. The aim is to have a stream of coffee which looks more like honey than a gushing torrent. A grind which is too coarse results in a “gusher” and will likely taste awful.
Grinding coffee too fine can “choke” the ROK. This means regardless of how much pressure is applied to the levers, very little-to-no coffee comes out the bottom. If your coffee seems very restricted and comes out in drips (or not at all), you’re grinding too finely. Try a coarser grind.
Typically, the espresso grind you get from a grocery store or cafe is too fine. If you’re buying pre-ground coffee from a café, ask them to grind it one or two steps coarser than espresso. If you’re using the grinder at your grocery store, set it one or two steps coarser than espresso. A symptom of internal damage from exerting too much force on the handles is pressure loss; i.e. air escaping from the top of the ROK while pressing a shot. In most cases, this can be remedied with a replacement O-ring and/or plunger. NOTE: Damage of this sort is not covered under the ROK warranty!
Don’t crank the portafilter into place
The portafilter will lock in position using only moderate force. “Cranking” the portafilter into the lock position can damage the main plastic cylinder, the filter seal, the bayonet ring, and/or the portafilter itself.
If you find the portafilter is unwinding as pressure is being applied during a shot, you need only clean the coffee oil and residue from the bayonet ring groove that the portafilter slots into.
Do not put your ROK in the Dishwasher!
Do not soak your ROK with denture tablets!
Do not use abrasive scouring pads on the outside of your ROK!
Give Your ROK Some Love
Dry your ROK thoroughly after each use.
This will help you maintain the shiny finish of the body of the ROK. It also reduces the chances of mineral build-up (lime scale) and resulting corrosion. Allowing water to sit on the body of the ROK will, over time, tarnish the finish and create water marks which can be difficult to remove.
Cleaning the portafilter
Coffee residue can build up under the basket in the portafilter. Take the basket out when cleaning your portafilter.
Removing mineral buildup (lime scale)
If you notice mineral deposits around the rim where the aluminium frame meets the plastic cylinder, it’s time for a little maintenance. Failing to remove mineral deposits can result in corrosion and permanent damage.
To make cleaning easier, you can remove the cylinder. This only requires that you undo the main screw (joining the connection arms) at the top of the ROK. This will allow you to take out the plunger, and the plastic cylinder should just twist to unlock and pull straight up and out.
The unpolished aluminium inside the ROK may also have mineral deposits. Don't use a abrasive scouring pads to clean the inside. Use a soft cloth and a a 50/50 solution of white vinegar and water to wipe the inside of the frame. You won't remove all marks or deposits and that's ok.
Polish your ROK
If you really want to bring the sparkle back to your ROK, you can use aluminium polish.
Making Better Shots
Use fresh coffee and grind right before making a shot.
For an average coffee dose of 16-18 grams (about two ROK scoops of whole beans), your resulting shot should be between 30 and 60 ml (between 1 and 2 ounces). Running shots too long can lead to excessive bitterness. Too short, and your shot may taste acidic (some folks prefer this). Your shots will vary depending on the coffee you use. Experiment to find a ratio that works for you.
Have fun and enjoy your coffee!