WARNING: See comments. The plastic parts of this espresso maker contain BPA. I am no longer using mine. H/t to Harry from Coffee Chap for getting the word directly from ROK.
Something a little more bobo than usual:
I was given a ROK manual espressomaker for Christmas, and have used it daily since to give an accurate characterization. One of the small amenities I sorely missed during the 13 days of cold blackout after Hurricane Sandy was morning espresso. (We made Turkish coffee on the gas stove.) With the ROK, as long as we still have natural gas and running municipal water, I will be able to drink espresso.
I have a solid background with consumer espresso machines. I broke a Saeco trying to clean the group head (the retaining screw stripped – the end) after 3 years; I burnt out the thermostat on a Francis! Francis! after 5 years and swapped its boiler parts into a 1980s Espresso Cialda after finding the latter in a basement with the filter basket missing. All those machines developed thermostat problems: after a couple of years they couldn’t regulate boiler temperature, overheating the water until the espresso was a thin, scorching brew.
Overall, the ROK makes an excellent espresso. It is a little more work than an electric pump-driven machine, but the quality and kinetic experience is worth it. But there are a couple of qualifications to my praise.
I used Doulton-filtered water and grounds from a Braun burr grinder. I had to use Starbucks espresso beans because that’s all I could get locally after trying illy (disgusting, thin, sour) and Gevalia (sour, thin, revolting) and Fairway’s bulk beans (artificial flavor fumes lingering). For years I bought the darkest roast I could get in bulk at Costco, but they stopped carrying anything above a medium Colombian Supremo. I must start ordering online.
Tamping the grounds
You will note that the included spoon has an ergonomic divot for pressing with your thumb while tamping the grounds. This is because a firmer pack than used with electric machines yields better taste and crema.
The ROK, into which you must pour boiling water and then press it out with an action like that of a wing corkscrew, won’t suffer thermostat failure. But its body is an alloy that loses heat quickly, and requires preheating of everything to get a passable brew. You must fill it to top with boiling water, let it sit a moment, then flush it through the empty basket, preheat the cup with kettle water (not the flush water which has already gotten much cooler), then half-fill the ROK with water for your espresso all in a short period of time. If you do that the espresso will come through warm, but never quite hot. Given the predictable failures of machines that cost up to twice as much, that’s not a big deal.
A review I found complained about the ROK’s crema, and it’s true: crema’s not easy to get. I found it works best when you make the cup, then add ~tablespoon more of boiling water from the kettle and press it through the grounds. The higher ratio of air to water in that second press almost always lends itself to a ready froth.
Generally, the construction of the ROK is solid and ingenious. But its finish will not stay perfect. This is because steam rises from the chamber where you pour the boiling water. The steam acts on the joint where the aluminum wings are pinned by a bolt that is probably stainless steel, causing galvanic corrosion. The finish of the ROK is highly polished and probably anodized, so where this corrosion happens the anodized layer cracks and aluminum oxidation (rust) happens in the cracks. It won’t affect its function but as you can see, aesthetic fetishists will be bummed.
Another flaw, this one more serious, is the choice of ridiculous rubber feet that stick to the bottom. As a metalworker, I can tell you that anodized aluminum is an amazing material. Almost anything (paint, adhesives etc.) will stick to it, much better than it would to raw aluminum. After anodizing and painting aluminum, it can be sealed to prevent anything sticking. So if the base were aluminum, I would have anodized it, stuck the feet on, then sealed it.
But the base must be corrosion-resistant because standing water and coffee residues will sit on it. You can see a seam where it is bolted to the main body. As such it is almost certainly a chrome-plated zinc alloy (which makes me wonder if the entire body is not that, maybe that zinc-aluminum-magnesium-copper alloy I’ve seen used in jewelry…but the finish-cracking around the joint mentioned above suggests aluminum). The very chroming that strengthened the base’s finish made it too sheer a surface for sticker-feet to cling to, and one popped off this morning. Since the user presses down with equal force on the two arms, effective use requires that the unit be skid-proof. Eventually all four feet will come off and you’ll need to apply a full-bottom adhesive rubber base, covering the “designed in London, made in P.R.C.” language—nothing lost.