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the quickshot review - grindenstein knockbox
Grindenstein Knockbox
Author: Mark Prince
Posted: April 18, 2006
QuickShot Review rating: 8.8
feedback: (46) comments | read | write
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The Grindenstein is one of those cute looking products that can be considered a "necessary" (coined from our forums) for anyone doing espresso in the home. Here's a typical CoffeeGeeker shopping list:

Grinder - check. Espresso machine - check. Fresh coffee - check. Good water - check. Mad skillz - working on it. Tamper - check. Knock box - uh.

Many new home barista types end up using the sink, the garbage, the side of a table (messy carpets - ewwww!), whatever - many people I know that have gotten into espresso seem to be missing a knock box. And I sometimes ask why. The answer? Too big, too ugly, too goofy, slides around the counter, no room, you name it.

The Grindenstein is designed to answer a lot of those questions. Can't be called ugly (nice look, cutsy colours); can't be accused of sliding around the counter (super-grippy rubber feet on it); can't say you cannot find a place for it - it's designed to sit on your drip tray, under your portafilter spouts. And, can't be accused of being too big - cuz it's not - it's downright small.

Out of the box

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We got the four Grindensteins shipped individually, and I was surprised at the size of the shipping box. It's small. Really small. I guess I'm just so used to the Reg Barber big box that these seemed tiny.

The diameter of the knock box is 11cm (5.25"). It is 10.5cm tall (4.15:") tall in the back (including the rubber feet), and the dip in the front tops out at 7cm (2.75"). The actual knock bar is approximately 8.7cm off the ground (top of the bar). And the bar's arms extend past the sides of the knock box, giving it a width of 13cm (5.15").

It's small for a reason, according to Dreamfarm - they wanted it to fit on the drip tray of most consumer espresso machines when not in use, easy to slide under the spouts of the portafilter. I'll talk more about the size later on, with comparisons to other knock boxes.

The colours are vibrant - the red pops. The dark blue one is, well, dark blue, and seems purple in some light. The black is a nice soft black, not glaring. And the white model is white with black accents), but not popping white - more a muted white, like what iPods are coloured.

The build? A quick overview - the knock bar is a thick bar of plastic that juts out of either side of the box. It is held in place by two rubber like grommets that look suited to the task. The middle is covered by a piece of rubber like material that is approximately 4mm thick. The container itself is plastic, and seems like its fairly durable - it's a thick kind of plastic with a tiny bit of give (it's actually quite stiff plastic, but enough give, I assume, to withstand a lot of banging). The four rubber feet on the bottom are connected to the knockbox pretty securely - they actually fit through the bottom of the knockbox - no glue here.

The product looks well built - just it seems so tiny.

Using the Grindenstein

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Those are 58mm pucks in there. It's small.

Most of the machines I test and use have standard 58mm filter baskets, and commercial portafilters. Which are pretty big. I'm currently testing a Vibiemme Domobar Super (which we got through Stefano's Espresso Care in Oregon), and the portafilter for that E61 equipped machine measures 8.5cm wide at the bayonets which is the same width as the rubber tubing in the middle of the knock box. Another machine I'm testing right now is the Krups XP4020 with a filter basket size of 52mm, and a maximum width of 7cm at the widest point (it has three bayonets, so they don't increase the diameter as much as a two-bayonet portafilter does.

The thing is, I had concerns about the small size of the Grindenstein vs. the hugeness of the portafilters I typically use. But there's nothing like actual use, so that's what I got into.

Everything on this knock box is solid - the fit and finish is good, the rubber is dense without much give in it, and the plastic is thick. Translation - giving your portafilter a good whack on this makes a hella lot of noise ;) Much of the knock makes its way right down to the counter, and it is loud - louder than the softer rubber bar on the Reg Barber knockbox I use regularly, and louder than the Starbucks knockbox (which has lots of plushy rubber as its base).

There's good and bad in this. The good is, I was pretty sure this thing would stand up to a lot of abuse, and would last a long time. The bad is, in the morning, it's guaranteed to wake up anyone still sleeping. After a few days of using this knock box, I had a a knock on my door - a neighbour in my condo asked if I could stop hammering at 7:30 in the morning. Well what can I say - we have thin walls here.

I do find it's very effective as a knockbox, but the small size of the unit sometimes prevents pucks from dropping cleanly out. When using a machine without a pressure relief valve (ie, the finished puck is all soupy and messy), one or two knocks on the Grindenstein, and most of the mess is in the knock box, with little or no splatter or spash of the wet grinds - the side walls do an okay job of containing the mess. Of course, if you're lacksey-daisical (that's how you spell it, right?), it's very easy to make a mess.

When using a portafilter with a relatively dry and solid puck, your first knock may jar the puck loose, but the tight space in the knockbox will sometimes keep it in the portafilter. When you use a large knockbox, usually you're hitting the edge of the filter basket, and at least for me, the puck almost always pops out on the first go. With the Grindenstein, it takes two, sometimes three knocks, or a knock followed by a "wiggle" to make the puck fall out. I also found that when knocking a dry puck, sometimes, puck particles would spray around the counter.

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52mm Portafilter
Here's the Grindenstein with the 52mm Krups portafilter.
This is a 58mm portafilter from a Vibiemme Domobar.

I found that with the Krups machine and portafilter in use, this knockbox needs to be emptied every 4th or 5th use, but with the Vibiemme, ever 3rd or 4th use. If you're a typical user of this device, that's acceptable - empty it every day or two. For me, the size (again!) was a bit annoying after a while.

On the Size Issue

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Comparing sizes
Even though the steel model looks bigger, it only holds about 50ml more "volume" until stuff starts to spill out.

I keep harping on the size, so I decided to do a liquid volume measurement of the Grindenstein as compared to a very beat up steel square knockbox (pictured to the right), and also the humongous Reg Barber knockbox.

Grindenstein can hold 522 ml of liquid, or just over half a litre.

Square metal knockbox holds 572ml of liquid.

Reg Barber holds a whopping 2240ml (2.2litres) of liquid.

Here's the surprise for me - the Grindenstein holds only slightly less than the square knockbox. And thinking back to how I used the square model (and the long gone Starbucks rounded steel knockboxes), they required as frequent a cleaning and emptying as the Grindenstein does.

It's important to say that Grindenstein didn't chose this size arbitrarily though. It was planned, and no, not (just) to save shipping or storage costs. They designed it with three things in mind.

  • it should be big enough to at least accommodate commercial portafilters
  • it should be short enough (and shallow enough, depth wise) to be able to sit right on the drip tray of most consumer espresso machines
  • it should be short enough to fit on the top rack of any dishwasher.

It does fit all of these criteria, and I have to say, it does look very good stored on the drip tray of an espresso machine. It also catches the stray drips from machines that don't feature a 3 way solenoid valve.

And as you can see from the size comparison with the square knock box - even though the Grindenstein holds only 50ml less volume, it has a substantially smaller "look" than the square knock box. This is a major plus in my book - it's deceptively small. ;)

Long term use

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200 Uses, Grindenstein
This white unit was used approx.200 times. Aside from a slight scuffing on the bar, and a very slight discoloration inside, it looks new. Dishwashed at least a dozen times.
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150+ Uses, Steel Box
This box has seen roughly 150 uses, and wear is quite evident. Look at the grommets holding the bar in place (sliced), and I had to tape it up with electrician's tape. Dishwashed once. Badly.

My initial guess that this product would stand up well seems to be proven true. I'm going to use the square stainless knock box as a comparison.

Within about 50 "uses" of the square steel knockbox you see in the pictures on this page, I noticed that the rubber on the solid steel bar was starting to chaff away. Within about 75 uses, it was getting noticeably louder, and the same problem I had with the Starbucks knockboxes was evident in the square model - the grommets holding the knock bar in place were cut by the sharp metal edges they sit on.

But the worst was when my partner accidentally put the entire thing in the dishwasher - knock box in the upper tray, the knock bar in the cutlery tray. The rubber on the knock bar melted almost entirely away (and ended up sticking on almost everything else in the cutlery tray. Both her and I spent some time picking it all off ;) This knockbox currently sits retired, with a bar wrapped with half a roll of electrician's tape (black tape) in lieu of the melted off rubber.

By comparison, we just passed roughly 200 uses on the white Grindenstein (yes, I keep a little notepad with check boxes next to it), and it looks almost brand new! And I even picked the white one to "torture test" because I figured it would be the one most susceptible to showing wear. But nope....

The rubber has the slightest of scuffs and marks on it (most likely from hard edges of portafilters). The arms are holding up well, and the big, beefy rubber grommets that hold the plastic bar in place look no worse for wear. The white interior does show the slightest discolouration inside from all the coffee that's passed through it (lessee - 18g dry, / maybe 30g wet, times 200+ uses = a lot of coffee!). This thing is taking a pounding, but still looks studio-photography ready. I'm impressed.

I also do find it very convenient when testing machines. I have both the black and the white ones in use - black with the Vibiemme Domobar Super, white with the Krups and with the Solis SL-70 (going head to head with the Krups). All three machines are in my kitchen, where counter space is at a definite premium, and the ability to put these right on the drip trays when not in use helps keep things very tidy.

I also enjoyed the (unexpected) benefit of being able to place the Grindenstein directly under portafilters on a machine while doing my "portafilter wiggle" cleanups of the groupheads. On the Solis and Vibiemme machines, there's just enough clearance for me to be able to remove the portafilters completely, or lock them back into place while the Grindenstein is sitting on the drip trays. This means I can fill it, and easily empty it in the sink, instead of dealing with messy, overfilling drip trays all the time.

I also really like and appreciate how grippy the rubber feet are on this knockbox. They have a very low profile, but as the saying goes, "do the job". My Reg Barber wood and metal knockbox is beautiful, but it slides all over the freakin' place. The Grindenstein acts like it is glued to the kitchen counter. I did notice though that two of the samples we were sent had moulding "ridges" on the bottom of the rubber feet that were prominent enough that they reduced the grip of the feet on the counter. A quick sanding down of them with a nail file (!!!) fixed that problem.

I did find that the Grindenstein was not as easy to keep mess-free as my initial testing indicated. I did get a bit lazy at times, and I would end up with grounds everywhere. If the sizing was a bit bigger, I know it would be less of a problem. In fact, just for usability, I would like to see the Grindenstein's size changed so that the distance between the bar and the front or back "wall" of the knock box was at least the size of a 58mm portafilter. This would allow me to more easily knock pucks out of the big boys.

(nb - as I was finishing this review, Dreamfarm informed me that the bottom of the Grindenstein would be getting a redesign, moving from "feet" to a rubber ring all around the outer diameter).


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A messy Grindenstein
Trust me, it cleans up nice. This was the "before" picture, done before the 200 uses photo ;)

Yes, it's small. But the Grindenstein is very well built, and bonus - it looks very cool too. I recently had a small dinner party, and two of the guests, while in the kitchen, went "ooooo what is that!!!" all excited and stuff. People getting excited over a knockbox? Happens at my place now, thanks to the Grindenstein.

Do I wish it were bigger? Yeah. Do I wish it were cheaper? No, I think $34 Cdn, or $29 US, delivery included is a decent price to pay for this, shipped all the way from Australia.

Do I have a list of pros and cons to round out this review? I sure do.

Grindenstein Pros
- Looks wicked cool
- Very durable
- Dishwasher safe (upper rack)
- Rubber feet are extreme grippyness - my Reg Barber slides all over the place.
- Materials used are absolutely first rate. Other knock box makers could take lessons here.
- Price is very reasonable
- Ability to store on the drip tray is cool, and convenient.

Grindenstein Negatives
- Size, though, it makes very good use of it's small size.
- I did find that sometimes, wet, soupy pucks would splash over the sides of the knock box. Rare, but it did happen.
- initial finish on the rubber feet on two of our samples had moulding ridges - less grip. I sanded them down, and it was much better.
- did I mention size?

This size is ideal for a lot of people, especially those with small counter spaces. And I know I'm clouded by the fact that my day-to-day knockbox is a 2.2litre holdin' massive commercial knock box. As much as I really like the Grindenstein, I think an increase in either the diameter or the overall size (perhaps an XL version for da CoffeeGeek?) would bump this product up another full point and a half. But as such, I do give it a

7 out of 10 Rating.

The Grindenstein is a good, well enginered product. If Dreamfarm decides to make a larger version, I'd happily buy it, and who knows, maybe even replace the uber expensive Reg that I currently have sitting next to my La Marzocco Linea hybrid machine.

CoffeeGeek sincerely appreciates Dreamfarm for sending us four of these knockboxes. We also thank them for sending two of the four to be given away on a future CoffeeGeek podcast - stay tuned to the show to find out how you can win one of these great knockboxes. In the meantime, Dreamfarm is taking orders and shipping these knockboxes daily. The prices are $33.95 Cdn for those of us in Canadaland, and $28.95 US dollars for youse Yanks; prices include delivery and shipping.

QuickShot Review rating: 8.8
Author: Mark Prince
Posted: April 18, 2006
feedback: (46) comments | read | write
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