OK for milk based drinks, forget about straight espressos.
Positive Product Points
Quiet operation, solid build, plenty of steam, reasonable price, over three years of use without any technical problems.
Negative Product Points
SL-80: Very poor temperature stability, way too much pressure, this machine would brew through concrete. Never managed to get a better than average shot with it.
This review actually refers to a Solis Crema SL-80 220 Volts bought in Switzerland about three years ago. As I understand it, the SL-80 is the European version of the SL-70 sold in the US, same guts, different switch board and colors. I have had some time to play with it.
The SL-80 is a quiet machine; the vibrating pump is very well damped and doesn’t transfer its vibrations to other components. All you hear during brewing is a quiet buzz. The Solis provides plenty of reasonably dry steam. I found it fairly easy to obtain microfoam with it, despite its single aperture wand tip.
After a while I got frustrated not being able to get a decent espresso out of it. I tried different tamping methods from no tamping to something-is-going-to-break tamping; tried to ‘temperature surf’ (pointless on this machine); tried different grind (you need an atomizer not a grinder)… but nothing did it! The initial problem, I thought, was the pressure. In order to get a 25 sec shot you need to use the pressurized filter, grind the beans to dust, and tamp it very hard. Those requirements made it difficult to get consistent results.
The Solis company uses the pump pressure of this machine as a marketing argument. The more the better, they suggest, and they advertise it to be a monstrous 19 bars. That’s 10 more than what is usually acknowledged to be the ideal pressure. In order to have a better idea of what was happening, I installed a manometer between the pump and the boiler. The manometer had a limited range, but it showed a pressure well in excess of 13 bars. In order to reduce the pressure, I shortened the spring in the relief valve (the valve designed to protect the machine against dangerously excessive pressure.) The spring was shortened until it made the valve open at a pressure of 9 bars. It was now possible to work with a more manageable grind size, non-pressurized filter, and 30 pounds tamping to obtain a 25 second shot. Goody!
But still the taste wasn’t there. Could it be the temperature? So here we go with the Shomer-like Fluke digital thermometer and all that jazz! To make a long story short, this machine is a temperature rollercoaster. Inside the machine, a little dial let you adjust the temperature at which you want the rollercoaster ride to start (must be engineer’s humor), hmm let’s see a few degrees up or down. It doesn’t matter anyway, a few seconds later into your brew, the temperature will be nowhere close to where it initially was. The water temperature in the portafilter is exceedingly sensitive to the water flow going through it. The water flow is a function of the hydraulic resistance of the coffee ground. The most insignificant change in tamping or grinding will change the water flow which will in turn make the temperature vary. And I can’t see any way to correct this with the Solis.
Follow up comments: Mark Prince shed some light for me on the differences between the SL-70 and SL-80. It seems I was wrong in assuming they were almost identical machines. Here is what Mark had to say about them:
“The mystical SL80. There are reasons Baratza doesn't import this any longer (I'll explain more about this in the DR, under History), but also I think that the SL70 is a predominantly different beast inside with regards to electronic controls and such - it has little that the -80 and -90 models do for electronics. The -70 is more of a mechanical, old-style beast for making the espresso, relying on thermostats and mechanical controls to regulate the temps and pressures.”
And concerning temperature:
“This was a known problem with the SL-90, but about two years ago, Kyle Anderson got the Swiss to modify how this works (as well as the programmed temps), at least for the N. American shipping models. It was quite a chore... apparently it's hard to convince the Swiss that what they are doing could be faulty :) :) “