This machine is beautifully engineered with form and function integrated into an aesthetically pleasing appliance. In short, it is a joy to use.
Positive Product Points
Well-designed dual-boiler PID-equipped machine capable of creating consistently excellent ristrettos and milk drinks. It is designed to be used on either a 15 or 20 amp circuit, and can be direct plumbed with included hardware. The PID control allows separate adjustment for each boiler. The machine also features an E61 group head and a quiet rotary pump instead of the noisier vibrational pump. The machine itself has an external polished stainless-steel shell preventing the exterior from getting hot to the touch. A separate switch controls the steam boiler. The low water sensor has an alarm. The Duetto is equipped with an articulating no-burn steam arm, and is supplied with high quality portafilters. Very high quality fit and finish.
Negative Product Points
The cup warming tray rests on rubber bumpers located on the top of the internal shell. These bumpers come off too easily when the tray is raised, and you will need to affix them with silicone. The machine comes equipped with SS feet with felt on the bottom. This felt causes the machine to "skate" on a smooth counter top. This was remedied by placing a thin piece of rubber underneath each foot. There are sharp edges at the back of the drip tray. There are two extra-cost options which I believe should be standard: a stainless-steel handle kit for the cup warmer, and a 15 amp adapter cord.
Initial setup required me to remove the outer jacket, attach the capillary tube, and replace the jacket. You should be aware that the outer shell contains tabs which can (but are not meant to) engage the holes on the side of the inner shell, so replacing the outer shell requires a bit of juggling to get it to seat properly. It is a heavy machine (72 lbs shipping weight), and I recommend that two people lift it to the counter. I filled the reservoir, attached the 15 amp converter cord and turned the machine on. It was ready to go in around 1/2 hour. A nice touch is the fact that the switches are shrouded in rubber decreasing the possibility of inadvertently shorting the machine by turning it on with wet hands. After readjusting my grinder I was pulling consistently excellent shots within 3/4 of an hour of the initial setup. If, at a later date, you wish to change the amperage the programming can be reset using the PID buttons -- no need to open the shell.
The 15 amp setup does not allow the boilers do not heat simultaneously. Instead, preference is given to the water boiler over the stem boiler. Flashing lights on the front panel inform you which boiler is being heated. Nevertheless, this arrangement does not cause any difficulty in my home environment. When making a ristretto I switch off the steam-heating element using the toggle switch on the right side of the machine. In daily use I find that the Duetto requires about 30-40 minutes to thoroughly warm the boilers, the E-61 group head and the portafilter. The dual boiler arrangement allows me to steam milk at the same time I am pulling a shot. The basic operation of the machine is almost intuitive. I fill the portafilter with appropriately ground coffee (I use Black Cat from Intelligentsia), tamp, insert the portafilter and depress the lever. After the coffee extracts for about 25 seconds I raise the lever to stop the extraction. The rotary pump makes for quiet operation.
A word about the low water sensor: when the weight of the reservoir is low you will hear a beeping noise. However, the boilers continue to heat. This is behavior is different from my Isomac which simply shut off the electricity to the entire machine.
Steaming milk is simple once you get used to the huge amount of steam the Duetto produces. Making a good micro-foam required a bit of practice for my wife, but I had no difficulty. The articulating no-burn steam wand is easy to manipulate, and once you get the feel for the amount of steam it produces you'll love it. I understand that the steam pressure is programmable through the PID. I haven't tested the PID, other change the boiler temperature. The PID provides remarkably stable temperatures. My experience leads me to believe the PID eliminates the need for flushing the head prior to pulling a shot.
Since this is being used as a pour through machine you need to remove the water reservoir to refill. I find the fit a bit tight in slipping the reservoir past the siphon tubes. Although my water hardness is in the acceptably soft range, there is some calcium and magnesium in the water which will inevitably lead to scale buildup over time. I opted, therefore, to purchase a couple of in-line cation exchange cartridges. The cartridge fits over into the end of the siphon tube and is inserted into the reservoir. I use a charged cartridge for a couple of weeks before recharging. The cartridge can be recharged by soaking in strong brine overnight and rinsing out the excess brine with water.
The fit and finish on this machine is first-rate. Aesthetics is always a difficult thing to rate, because it is inherently subjective. Machines like this always remind me of what the engineer of a steam locomotive might be looking at if his controls were in stainless steel. This style of machine seems to inherently lack the grace of manual, lever machines or or sleeker designed machines machines like the Vivaldi II. Nevertheless, the design speaks of refined functionality. Were I to try to design a machine I think I would try to have a substantially lower body. But then, I bought this machine to make great coffee, not to hang on a wall.
I bought this from Chris Coffee. I am a repeat customer, so that should tell you a lot about my experience. The entire staff could not have been more helpful. Mary is an excellent salesperson, and a delight to deal with. I think Chris Nachtrieb (owner) really cares about pleasing his customers, and that attitude permeates the entire staff. I had a few minor issues with the machine when it arrived and Chris quickly resolved them. I wholeheartedly recommend Chris Coffee.
Three Month Followup
I continue to be impressed with this machine. I achieve perfect pulls every time. The PID is easy to reset and maintains temperature and pressure nicely. The ultimate tests of any tool are the quality of its output (espresso and steamed milk), the ease of use, and its durability. I have owned the machine for three months, and so I cannot speak of its durability. However, with respect to the other criteria I have no hesitation in recommending this machine to anyone serious about making high quality espresso. The only minor annoyances are that it is a bit cumbersome to remove the water reservoir for refilling, and it would be nice to be able to remove and replace the splash grate while leaving the drip tray in place.