The ROK can take some getting used to. Give yourself plenty of time (and coffee) to experiment with it and you’ll find a method that works for you. Remember, the most important factors are the coffee and the grind.
Don’t buy coffee that’s two weeks or more from roasting.
Don’t buy coffee that doesn’t have a roast date on the packet.
Old coffee tastes flat and produces little crema.
“Best before” dates on coffee are B.S.
Grind coffee as you need it. Ground coffee stales very quickly. If you’re buying pre-ground coffee from the supermarket you’re going to have a bad time. Pre-ground coffee is unlikely to produce shots with rich crema.
Use a burr grinder. Blade grinders stink – seriously, they’re no good.
Grind your coffee fine (but not too fine). You’ll find that the finer you go, the harder it is to push the levers down. That pressure is a good thing as it means you’ll achieve better extraction and more crema. However, if you go too fine you may not be able to press the levers and/or no coffee will come out – this can prove messy and potentially dangerous. Find a balance that works for you.
You’ll know if you’ve gone too coarse as there will be little lever resistance and the coffee will “gush” out. It will look and taste watery, bland and bitter.
You may need to change your grind settings for different coffees as they may run fast or slow, depending on a number of factors.
There’s a scoop inside the ROK tin. Two flat scoops is roughly 18 grams. I have had good results dosing as low as 12 grams. Anything above 20 grams can be problematic.
Tamp firmly and evenly. This can be tricky with the included tamper (it is also the scoop). If you’re looking for a worthwhile upgrade, get a proper tamper – you’ll notice the difference.
I only press the levers once. I press firmly, but not fast, until the first coffee starts dripping. Then I slow down a little for the remainder of the shot. Stop pressing the levers to stop the shot.
What you want to see is a slow trickle of coffee, almost like honey. You don’t want the coffee to drip too slowly or gush out quickly.
While you’re grinding your coffee and getting organised, add hot water to the top of your ROK to warm it up. This ensures the water you press through the coffee will be hot enough for a good extraction. Once you have everything ready, discard this water.
Don’t waste any time. Get some fresh boiled water in the top of the ROK and press out your shot. Once the water is in, don’t waste time starting the lever press. The water will lose heat as it sits there.
JUST ADD WATER
Fill the top chamber to about 2cm from the top. Overfilling can lead to spillage when raising the levers.
Stop the shot before all of the water comes out. The top chamber holds about 100ml of water and you only want 30-40ml to end up in your espresso. Pressing all of the water through will give you water, bitter coffee with little crema.
Put another cup under the ROK and press the extra water out. This will make cleaning the portafilter less messy.
You’ll end up working out what works best for you but here’s some tips on tasting.
Bitterness: The shot probably ran too long or had too much water passed through it. Bitterness tends to come out late in the extraction.
Acidity (some folks call this sourness): There’s a few possibilities here. You may have lost too much heat during preparation or ran the shot too short. Lighter roasted coffees can have more acidity. Some people like acidity in their coffee, some don’t.
Sweetness: The sweetness in a shot comes out somewhere in the middle of the extraction (for a 30 second shot) so if you time it right you get a great balance of acidity, sweetness and bitterness. It can be tricky (and frustrating) with a manual lever machine and that’s perhaps why the lever (and ROK) fanatics I know are so passionate about their machines.
Also, sometimes the coffee I buy just sucks and no amount of tweaking can fix it. Bin it and start fresh.
The ROK is easy to clean. Rinse it under a tap. You can also run some clean water into it and press it out .
Dry your ROK! To maintain that beautiful shiny finish, dry your ROK thoroughly after use. Remove the flexible silicone filter screen from underneath the ROK to allow the inside of the chamber to dry.
Don’t give up. Experimenting is the key to producing great coffee with the ROK. If you Google for tips, you’ll find some contradictory information – there’s no one right way. That being said, following the tips above will give you a very good chance of success.