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Sunbeam EM6900 Twin Thermoblock Espresso Machine.

Given my opinion of thermoblock machines in general, reviewing the Sunbeam EM6900 Twin Thermoblock espresso machine might be thought to be a bit unusual. However, this machine is supposed to have been designed with considerable input from World Barista Champion Paul Bassett, making it worth at least a closer look. This is meant to be the first "consumer level" machine able to brew and steam simultaneously, as well as using a "commercial" sized portafilter and baskets.

I purchased the review machine from Myer Melbourne for the RRP of $599.00, carted it back to the office and got straight to work. First off, watch out for the box. The machine and accessories come nicely packed in Styrofoam but the bottom of the box is one of those "fold in" designs and tends to open up and dump the contents when picked up by the handholds at the sides.

Unpacking all the bits and pieces, I ended up with:


Warranty, quickstart guide and manual.
800ml ss milk jug.
Measuring spoon (capacity 12g per scoop.)
Single & double filter baskets (NOT "industry standard" designs.)
58mm plastic tamper with ss base.
58mm twin spout portafilter.
Corrugated ss cup warming plate.
Rubber backflush disc (in rear door.)
And, of course, the machine itself.

The Sunbeam EM6900 set up next to a Silvia & Rocky duo. Accessories: 58mm Tamper, scoop, 800ml jug, warming plate.
Sunbeam portafilter on left, Rancilio portafilter on right. Inside the Sunbeam 3l water tank.

The machine is relatively heavy, with the top and base made from powder coated cast aluminium alloy. The middle portion is black plastic "skinned" with stainless steel, and the rear "door" stainless steel. It sits on adjustable feet; the rear feet have little wheels in them to allow easy movement on a bench.

Opening the rear door allows you to remove the clear plastic 3l water tank. The tank has a small resin water filter and a magnetic water level float sensor built in; water feeds via a "self closing" valve at the bottom front of the tank. There is a hinged flap at the top rear of the machine with a screened plastic funnel underneath it, allowing the tank to be filled without removing it by pouring water in from the top.

Steam & Hot Water wands are both chromed brass with swivelling ball joints; the steam wand has a single hole tip. The group is formed directly from the base of the thermoblock, and is stainless steel, as is the flat plate centre screw showerscreen. Group gasket is made of some sort of soft silicone type rubber, and is not designed for user replacement. The group collar is some sort of chromed alloy.

The drip tray and grill are plastic, with a little red "float button" which is supposed to pop up when the tray (capacity 1.0 litre) starts to fill. There is an outlet from the body of the machine feeding into the drip tray; this proved to be the exit for the solenoid pressure relief valve.

Looking more closely at the various components, the first thing I checked was the portafilter. It is indeed a true 58mm brass pf with a proper basket retainer spring. The "ears" are non standard, so it won't fit in other machines and standard commercial pf's won't fit in the Sunbeam. It is lined with a black plastic insert, as are the pf spouts, reason unexplained.

Then came the filter baskets, and things started to get a bit weird. The baskets, both single and double, are VERY deep and the holes in the base are obviously produced by a different kind of die than that commonly used in Italy. The single filter basket easily holds 21g (that is, 3 x 7g!) of espresso ground tamped coffee. The double basket holds 28g (quad!) ground and tamped. Due to the depth and volume of the baskets the grind setting for correct shot parameters is coarser than normal.

Sunbeam 21g single basket on left, standard 7g single on right. Sunbeam 28g double basket on left, standard 14g double on right.

Now I know Paul Bassett is a great believer in "updosing", i.e. cramming as much coffee into the filter basket as possible, but this is ridiculous. "Single" shots which are actually triples, and "double" shots which are quads throw the whole extraction equation out of whack. More on this later.

The machine has microswitch actuated rubber knobs for Steam and Hot Water on the left and right sides respectively, and a bank of LED's plus buttons control panel on the angled front. The control panel allows for fully manual shots, or is programmable for measured doses, as with commercial automatic machines. Other button combinations are possible for backflushing and cleaning routines. I found that the supposedly default programmed volumes were very different to those specified in the manual, 35ml for a single and 70ml for a double, but it's pretty easy to change them.
 
I filled the tank, turned on the machine, waited 5 minutes for the LED's to indicate "ready" and pressed the Manual Brew button. Pump laboured, nothing happened, no water flowed. Sunbeam may need to address the problems involved in pump priming and airlocks in the manual. I found that turning off the Brew button and opening up the hot water wand (and microswitch) resulted in water flow about 30 seconds later. After that the Brew switches all worked as advertised.

Then it was time to get "down and dirty" into the real stuff like water debit and brew temperatures.

As part of the brew program, the machine has a built in preinfusion feature, where 3 short bursts of water are pumped into the portafilter at 1 second intervals, then normal flow commences. I simply ignored this in all my shot and volume timings and started timing as soon as continuous pumping began.

Water Debit:  95 ml in 10 seconds.

Water Temperature: 90C, dropping to 86C after 40ml of flow.

Shot Temperature in the glass: 68C 

All these figures are within the specified range for espresso, and would indicate that while the limitations of thermoblock technology are still present, in the form of temperature variation during the shot, they have been throttled back into something acceptable.

Measuring brew water temperature (about 80ml at this point.) First shot, Sunbeam single basket.

PERFORMANCE

First, can the machine both brew and steam simultaneously? The answer is an unequivocal "yes", and is the best reason for using the programmed preset brew buttons rather than than the manual brew button and 3 hands.

ESPRESSO

I set up a Rancilio Rocky grinder and adjusted the grind until I got a 25 second 60 ml double shot using the supplied 28g basket and Espresso Meridionale coffee. The shot had plenty of crema but the flavour could only be described as "one dimensional"; it lacked the nuance I would expect from this blend. Then I remembered an exercise I was taught a long time ago, where a double espresso shot is separated into three 20ml portions as the shot progresses, and the portions tasted. The first 20ml portion had the same bland sweetness that I was getting from the Sunbeam. It would appear to me that if you use the supplied baskets and follow "correct" shot parameters that a large portion of the flavour that should be in the shot remains unextracted in the 28g puck.

I tested the theory by removing the Sunbeam double filter basket and inserting a "standard" Italian 58mm 14g basket (ex Coffeeparts.) The basket fit perfectly, and the shot pulled after a bit of grind adjustment had all the flavour I expected. Comparitive testing against a Rancilio Silvia showed more acidity and less body, very similar to an Imat Mokita or Gaggia Classic shot. Tested against the Mokita directly, body was identical but acidity still a trifle higher, probably a consequence of falling water temperature during the shot. Adding hot milk to the shots made any variation undetectable to my palate. I would therefore conclude that given decent filter baskets the machine can produce quality shots.

The Sunbeam has a "brew pressure" gauge on the left front of the machine; in theory shots in the (wide) yellow band are OK, shots in the black or red bands will be overextracted. In practice, the best shots were always in the black area, so I'd suggest the gauge needs some adjustment.

The beginning of the 28g pour. 2 seconds from the end of the pour.
Starting the 14g pour. Just before the end.

One major problem Sunbeam will face in the very near future will be the need to match the machine with a decent grinder. I tried using a little brick pack of "Espresso" coffee from the supermarket and got a 9 second 60ml shot of swill, with the most coffee I could jam into the 28g double basket and a handstand tamp. Customers who do not know the importance of grind in espresso preparation will undoubtedly complain about the performance compared to machines with "crema enhancing" portafilters. Consumer education is the only answer to this.

STEAMING

The steam thermoblock side of the machine (left) gets quite hot, and there is a vent on the upper left to allow the heat to escape. Grasping the machine on this side while you drag the steam wand into position is not recommended. Turning on the steam wand leads to a short gush of water, after which the separate steam pump begins to pulse out dry steam at fraction of a second intervals. There is enough steam pressure to get a "vortex" effect going with about 250ml of milk in the supplied jug, and decent microfoam is possible. However, compared to a Rancilio Silvia it takes about twice as long to achieve a milk temperature of 60c, and foam height is about half. In this respect the thermoblock and pump combination, while adequate, are no match for a boiler.

Sunbeam took 2 min 30 sec to heat 500ml of milk to 60C. Silvia took 1 min 25 sec and got much better foam.

HOT WATER

Opening the "Hot Water" knob turns on the "brew" pump and hot water is pulsed out from the brew thermoblock via the hot water wand. This creates an incredibly loud and annoying "thump thump thump" sound, guaranteed  to infuriate after the first few repetitions. Why the hot water is not simply streamed out with normal pumping I don't know; the temperature drop over 100ml (6C) is not large enough to make much difference in the cup.

INSIDE THE MACHINE

"No User Serviceable Parts Inside" is the phrase that best fits the Sunbeam. While it's easy enough to unscrew and remove the showerscreen, I would doubt that the group gasket could be removed without damaging it. Access to the interior involves removing about a dozen screws of various shapes and sizes; it's a technician's nightmare, as well as being (in my opinion) poor engineering practice. Once inside, the machine appears well built but cramped, with narrow diameter copper piping and brass fittings leading to and from the thermoblocks. It's obvious that the brew thermoblock technology owes a lot to the Krups Novo series. Both thermoblocks appear to have embedded thermocouples, bimetallic thermostats and overtemperature fuses. I'm not sure of the reasons behind the redundancy, although the machine has a "standby" mode which may use the different temperature controls. Access to the circuit board is difficult so I didn't attempt it, but it's pretty clear that it's not meant to allow for adjustments.

Some idea of the complexity inside the case. Machine "brain"; away from the steam thermoblock.

PROBLEMS

During the shot testing process the coffee streams produced by the plastic lined portafilter spouts were just a fraction far apart for my shot glasses. After unscrewing the spouts I found that the portafilter threads appeared to be industry (i.e. Italian) standard, and seconds later had added an o-ring and a single spout. Much easier.

After the first week of testing I had to take a break due to pressure of work. When I resumed, I was getting weird flavours & aromas in the shots, even after rigorous cleaning. Finally I saw that the freshly soaked and rinsed portafilter was still leaking brown goo, from around the black plastic liner. I removed the liner to find an interesting collection of growing things and coffee tars in the base of the portafilter. Thereafter I left the liner out. Sunbeam tell me that it is there to stop heat loss from the coffee to the portafilter, but leaving the portafilter in the group and flushing some hot water through it prior to a shot will prevent this anyway.

The coffee had some really funky flavours. No wonder!

I always ended up with a puddle under the drip tray after a couple of shots. The spout for the pressure relief valve is a fraction short, which lets water dribble around it to pool under the tray. Sunbeam are aware of this problem.

Towards the end of the second week of testing I came in one morning and turned on the machine to warm it up. After about 5 minutes there was a loud bang, a cloud of steam out of the cooling vent and an expanding puddle of water under the machine. Some quick testing established that something (presumably the water input pipe from the steam pump to the steam thermoblock) had come seriously adrift. Note that up until this time the steamer had only been used twice anyway, and wasn't in use at the time of the catastrophe. The brew portion of the machine was still in perfect working order and the control panel showed nothing amiss.

I rang the Sunbeam service hotline (without telling them who I was or what I was doing with their machine) and within 2 hours they arranged for a courier to pick up the machine for shipment to Sydney. It did help that I was able to correctly diagnose and explain the problem over the phone, and give a clear and logical outline of what had happened. 2 working days later Sunbeam rang to tell me that they would be shipping me a new machine, which arrived the next day. I certainly have no complaints about the level of service.

However, I have since learned (via coffeegeek.com) that I am not the only person to experience this problem. Discussions with Sunbeam have traced the problem to insufficient flare on one end of the pipe from the pump to the steam thermoblock, and they are correcting any machines they have in stock. They have not issued a recall on any of the machines sold to date, which (as I understand it) can't be all that many yet, since seafreight supplies are not yet established.

OVERALL

I would score this machine at a 7/10 at present. It has a number of minor problems and at least one major production fault, but it must be remembered that this is the first production batch. The warranty service (1 year overall, 5 year Pump) is excellent and Sunbeam have service centres all over the country. If Sunbeam are able to address some of the niggles and fix the production faults then the machine will be unmatched at the price.It comes with good functionality and a suite of accessories that Italian domestic machine manufacturers should take note of (but probably won't.) 

WISHLIST AND EPILOGUE

Would I sell the machine? The answer is a tentative "maybe". If I did, it would be with modifications to the standard equipment supplied. I'd want to replace the existing filter baskets and add an extra single spout portafilter, as well as getting rid of the plastic in the portafilter. Ideally, I'd also like to push the initial brewing temperature up 2C to 92C and see what effect it has on the shot quality. There have been indications that this is possible via external programmimg but I have yet to see the details.

I would be absolutely rapt to see the group collar and portafilters adjusted to "standard" fit so that aftermarket portafilters could be used, but doubt that this will happen.

I have had some discussions with Damian Court, Marketing Manager at Sunbeam, about several of these issues and he has indicated that they are being followed up. Until such time as a Mark II version is available and tested I can't give an unqualified "BUY" recommendation for this machine, but if Sunbeam do manage to fix all the niggles they will have a "category killer" in domestic espresso machines. Their biggest problem will be training the department store demonstrators in the barista skills needed to show the machines off to best advantage.