Why would a professional Barista upgrade from a Krups thermoblock to a semi-commercial heat exchange machine? Because itís the sane thing to do!!!
Having procrastinated for a few months, my hand was forced by the coffee rep who was able to get me the Office EB-61 Leva at a Special price. (The price I have quoted for this review is the US$ equivilant for the cheapest retail price I have seen in Melbourne.) I didnít get a test drive, only a brochure. So I read the experiences of CG Expobar owners and, with a little faith, handed over the folding stuff.
Out of the box
It arrived in itís brown cardboard box with the words ďMuy FragilĒ boldly printed on the sides. This machine is hardly what I would call ďMuy FragilĒ. At 25 kilos, it would make anything you dropped it on ďMuy Busted!Ē Seriously, this machine is solidly built. The quality of the construction is excellent, especially considering itís retail price.
Itís also good looking. From the first glimpses of itís chrome plated group head, as I peered through the open flaps, I was in as much love as one can be with a piece of espresso equipment. It may not have the finer body touches of an ECM Giotto, but itís a fine looking machine all the same. The on-line and brochure photos donít do it justice. (NB. The photo on this review page, at the time of writing this review, shows an Expobar Office "Control". You can see the "Leva" model at Expobar Australia.)
It comes with a double spouted portafilter (PF), single & double baskets, blind rubber insert (for back flushing), cheap & nasty plasitc tamper and a pathetic "Instruction" booklet. The machine can be plumbed in with an optional kit. I use the built in reservoir.
Plug it in, turn it on and brew some coffee
I RTFM and you should RTFM (even though it is a pathetic, cheap inkjet print excuse for some vague instructions on how to use a semi-commercial machine).
For those of you who want to know the factory set pressure settings, Iíll fill you in now. The pressurestat (pstat) for the boiler is set to cycle between 1.0 & 1.2 bar, which should produce brewing temperatures of around 94C. The pstat is adjustable but make sure you use a suitable screwdriver. The pstat looks like the one in this Coffeegeek thread
The pump pressure is set at 12.5 bar (regulated by an Over Pressure Valve (OPV)) and is also adjustable. (The OPV is fitted in line, immediately after the pump) Adjustment of the OPV can be made by turning the screw on the valve and measuring the flow rate. (Unfortuntely, I am unable to find the relavent threads on adjusting OPVís by measuring flow rates). The most accurate way of adjusting brew pressure/the OPV is with a PF fitted with a pressure guage. Unfortunately, the machineís casing has to be removed to adjust the pstat and the OPV.
The machineís 4 legs are very sturdy and all are adjustable. I used a spirit level when I made minor adjustments to the legs, in order to ensure the machine was absolutely level. (This helps you obtain even pours from the PF spouts.)
I filled the 2.9 litre reservoir by removing the steel lid and pouring water into the plastic tank. (The brochure specifies a 4 litre reservoir, but I think they replaced it with a smaller one to prevent heat damage to the plastic tank.) The tank is also easily removed, for filling from a tap. I use filtered water that has been remineralised. (The nasty stuff is removed and then the good stuff is replenished.)
I turned the machine on and allowed it to warm up for 45 minutes. The ďLevaĒ in the model name refers to the lever used to engage the pump for brewing. It also activates the 3 way valve that controls water flow to the brewing group. In the down position, the valve is closed. When lifted slightly, water is allowed to flow through the group without pump pressure (only works when plumbed in, and uses water pressure from your plumbing). When lifted completely, the pump is also activated. When the lever is returned to the down position, excess water is flushed back through the 3 way valve to the drip tray.
The brewing group also features preinfusion. When the lever is lifted and the pump is engaged, the preinfusion ramps the pressure to the coffee puck gradually, while allowing water to saturate the puck before full pressure is delivered. This method of brewing is not necessarily better than non-preinfusion methods but I enjoy the results. Thereís a great diagram on the "Giotto" page at the ECM site that shows how the thermosyphon and preinfusion systems are laid out. (Note: The ECM preinfusion system is not necessarily the same as that in the Expobar. However, it's informative all the same.)
As per standard heat exchange procedure, I ran a cooling shot through the group. (Read Dan Kehnís great thread on cooling flushes - How I stopped worrying and learned to love HXís.
I lifted the lever and superheated water spluttered out of the group. After approx. 250mls had been flushed through the group, the water had settled down so I knew it was no longer superheated. After dialling the Mazzer Mini grinder in, I dosed the portafilter and loaded it into the group. I lifted the lever and waited. After nearly 10 seconds of preinfusion, the magic liquid arrived. 25 Seconds into the shot, I pulled the lever down and sampled the results........Hmmmmm, tastes like burnt coffee.
Uh Oh.... The Dreaded Expobar Hotshots
Unfortunately, I had not flushed enough water through the group to cool it down sufficiently. This appears to be a common problem with Expobar machines. High volume cooling flushes (300ml - 400mls) seem to be required. I then used a digital multimeter, and thermocouple inserted through the portafilter spout, to measure the brew water temperature during cooling flushes. A 350ml (approx.) cooling flush was required in order to obtain usable brew temperatures. In order to avoid the brew temperature rebounding to superheated temperatures, I had to dose and load the PF quickly (no more than 30 seconds). If I follwed this procedure, I obtained good results in the cup. However, I was not happy with the amount of water used for cooling flushes. It was excessive and inconvenient (especially if you had to make more than 4 coffees in a session). IMO, the machine was not functioning effectively.
Expobar Fault Exposed And Rectified
I contacted the local distributor, and he agreed that the cooling flushes were excessive. I had the machine serviced, and they identified a faulty valve in the boiler that was causing the superheating issue. This was rectified and the machine now works brilliantly. How brilliantly? Iím glad you asked.
First, I have adjusted the pstat to cycle between 1.1 and 1.3 bar, which should produce a brewing temperature of approx 95C, which is ideal for the blend I am currently using. I have also adjusted the OPV to limit brew pressure to 10.5 bar . I did this using a PF fitted with a pressure guage. (Although this wasnít essential, I prefer the results at this pressure setting.) I allow the machine to warm up for 40 minutes, and I check the temperature of the brew water. It is consistently at 95C. Thatís without a cooling flush! I dose and load the PF, and lift the lever. Depending on the blend, I get 5 - 10 seconds of preinfusion and 25 - 30 second shots that are superb!!! I am now consistently producing shots with excellent mouthfeel and flavour profiles. I no longer have issues with superheated brew water, and the brewing temperatures are very stable and consistent. (NB. If the machine sits idle for more than 60 minutes, a single cooling flush of approx. 100mls is required.)
The ball jointed steam wand is a joy to use as it can be angled any way you like. Unlike some machines, where the wand can be rotated on one axis only, if at all. The large plastic tap handle is smooth and even when turned, and the steam power from the boiler is great.
My machine was fitted with a single holed steam tip, which works well with 200mls of milk or less. However, itís slow when steaming larger volumes. I obtained a 2 hole tip from the distributor, and itís sensational with 200mls or more. (I have seen single and 2 holed tips shipped with some machines in Melbourne. Ask for both.)
Hot Water Service
I donít use the hot water much, except for quick cup warming. The hot water arm is also ball jointed so it can be swung over the drip tray for rinsing the PF, if required, or swung out to the side of the machine for filling larger vessels. The hot water tap is identical to the steam tap.
The water reservoir tank sits inside the machine, on a spring platform that detects when the water level is low. When the water level is low, the boiler is automatically switched off to protect the heating element. A stainless steel lid (that doubles as a cup warmer) is easily removed to obtain access to the reservoir. The water line from the reservoir to the pump has a water softener fitted to help prevent lime scale build up in the boiler.
The drip tray is huge and is easily removed for emptying. However, itís fiddly to reposition.
The power switch is a standard lit rocker switch. When the heating element is on in the boiler, a seperate red light, on the front of the machine, comes on.
Cups can be warmed on top of the machine. However, they have to be removed with the steel lid when refilling the reservoir.
The vibe pump is noisy.
Backflushing of the machine is done by inserting the rubber ďBlindĒ disc into the filter basket and locking the PF into the group. Lift the lever, wait for 10 seconds and then return the lever to the down position. Water will rush out of the relief valve into the drip tray.
Access to the machines internals is excellent, after you remove the heavy stainless steel casing. A single piece of 2mm thick, polished stainless steel, wraps around the the back of the machine. It is secured by 2 heavy duty screws on the left, 2 on the right and 1 at the rear. However, as the casing is heavy, be careful when you remove it. The internals are well laid out and adjustments are easy to make.
NOTE: I DON'T RECOMMEND THAT YOU MAKE ANY ADJUSTMENTS TO ANY OF THE COMPONENTS INSIDE THIS MACHINE YOURSELF.
Here are some other interesting Coffeegeek threads:
Expobar Office...Cooling down the engine
Fine tuning temperatures on HX machines - A workable solution
Does your Expobar run hot? The (possible) fault and the fix....finally!
Please also read my follow ups below. I have outlined the components I have had to replace during the time I have owned the machine.