WHY BUY A COMMERCIAL MACHINE?
Ok, I could get excellent espresso and capuccino on my Solis home machine. Why should I pay three times as much for a semi-commercial machine? The espresso's a bit better, but certainly not three times better. The reason is convenience. To maintain perfection, you have to turn on your home machine, let it warm up, run water till the thermostat kicks in, temperature surf, make the espresso, switch to steaming, steam, and start all over again to get a second cap. Try doing that for company! So here I am, talking up my espresso, and my guests want a taste; 20 minutes and one very red face later, I decide it's time for a 24/7 machine that'll pull one shot after another, while steaming at the same time.
The Tea's boiler, valves, piping, electrical parts, E61 brewhead, and frame are the same for Isomac, ECM, Euro, Vibiemme, and many other machines using heat exchangers and E61 brewheads. This is emphatically a very good thing, since it is a high quality, reliable and proven design, and since spare parts are readily available.
A note on boiler size: These machines may vary, with specs (even for the same machine) running from 1.2 liters to 2.1 liters. I've talked to some German dealers, and they say the underlying parts supplier for all these models went from a larger to a smaller size to improve warmup time, and specsmanship is responsible for the rest of the quoted differences. My machine has the smaller (newer) boiler, which, judging by external dimensions (ca. 10cm diameter, 20 cm long) has about 1.4 liters gross volume. I thought I was buying a 1.8 liter boiler, but I don't feel upset, why? -- see my test below in the espresso making section.
The Isomac Tea is distinguished from other machines in this tribe by the following: The case is a thick and heavy polished stainless steel. It has an additional pump manometer. It's a little lower, narrower, and more understated; my kitchen is small, and it fits right in both in terms of size and in terms of its ultra-functional Bauhaus design. On the negative side, the hot water tap cannot be positioned over the driptray, so it can't be used to slosh hot water over the pf or cups. It can, of course, be used to draw hot water for ... tea.
The pump has good noise insulation and runs with a low rumble that's slightly quieter than normal conversational volume. There's no rattling unless the water tank lid/cup warmer is poorly positioned. This is good for those startled by sudden noises, because the auto-fill circuit will occasionally run the pump to keep the boiler water up to volume.
Most users of these machines like to keep their boiler pressure somewhere between 1.0 and 1.4 bar. The adjustment requires removing the case. So experiment with various settings all at one time (steam, measure the water temps, try some shots). I've found that higher settings in this range produce a syrupy low acid espresso, whereas lower settings increase the shot's acidity. I've personally opted for a middle range, and my machine cycles between 1.1 and 1.25 bar
After 15 minutes or more of disuse, about 7 ounces of water should be drawn through the brewhead prior to pulling the first shot, so the heat exchager water gets down to the correct 90 to 95C range (remove the PF while doing this, or it'll overheat). After that, espressos can be drawn as fast as you can realistically line them up -- in my tests, it could recover steam pressure and water temperature quickly enough to do about 30 to 40 milk drinks per hour. (This is the top 'speed' only! The machine uses a home style vibrating pump, so it's not meant for continuous commercial use)
The E61 brewhead, derived from the legendary Faema E61, the first pump driven, heat exchanger espresso machine, is a massive 9 lb chunk of chrome plated brass that stabilizes brew temperatures, and which has a spring loaded preinfusion system that ramps up the water pressure over a period of five seconds. I've found this machine to be very forgiving to grind and tamp variations, and the preinfusion technology may be the reason (I'm having fair success using a Solis Mulino grinder, which has overly coarse adjustment steps, while waiting for the Mazzer to arrive).
Another peculiarity of the E61 head is that it uses a levetta (Italian for little lever) to control the pump, preinfusion and three way valve. In the down (off) position, the three way blocks the water flow to the brewhead. In the 45 degree middle position, the three way allows water to trickle into the brewhead. In the straight out top position, it engages the pump for pulling the shot. When the shot is done, pushing the levetta all the way down flushes the excess water and pressure out of the brewhead via the three way.
After a few days using this group, I'm wondering why anybody ever went with anything else; it is awesomely cool, and very fun to use. Kudos on the manufacturers who revived it for home use.
At first, I thought the pump manometer was a frill, but it turns out to be fairly useful. First, pressure in the heat exchanger can get up to 6 bar on occasion. Leaving the levetta in the 45 degree positon for about a second bleeds off this excess pressure, and allows the preinfusion to work as intended. Second, the shot timing is correct when the pressure peaks between 9 and 10 bar during the shot. This is a more convenient a way of checking grind and tamp than using a stop watch.
Although I'm very satisfied, I can't give a blanket statement about how great the espresso is, since I don't have a lot of machines to compare it with. Compared to my Solis SL70, the espresso has a much heavier, buttery body, a redder denser crema, and more pronounced and distinguishable roast flavors. On the other hand, a La Marzocco FB70 (a premier full blown commercial machine) expertly used on the same blend, amplified body and flavors even more, and produced a more sudsy, thicker crema. Note that bright and varietal flavors can be varied to taste by changing the brew temperature via the pressure stat (see above).
Additionally, the ECM Giotto has won a number of taste tests against a range of high end home and semi-commercial machines. Since all the machines in the HX/E61 tribe have identical functional components, I find it reasonable to expect this result to hold for all of them too.
(My thanks to Doug Zell and Jose Iovino for their frothing help) I was afraid that I would experience what many other new owners of semi-commercial espresso machines went through -- the shock of dealing with a frother that heated the milk so fast that they didn't have time to build foam on smaller portions of milk. In this respect, the Tea is quite civilized. A 5 ounce portion of milk heats up in about 20-25 seconds, plenty of time to build up the foam. However, it's important to realize that the milk volume will only expand by about 30-40% rather than the doubling of home frothers.
The milk can be swirled to produce a pourable microfoam by keeping the frothing wand vertical, and frothing with the tip at the surface and center of the milk circle. The swirl is not a whirlpool as with single tip frothers, but rather a moire stationary wave. Finally, froth the milk only till the frothing mug is warm to the touch, then submerge the tip for the final heat up. It only takes a few seconds, so move one hand to the steam valve to shut it down fast enough. Rap the mug against the counter to get any remaining bubbles out before pouring.
Be prepared to spend a month becoming proficient, or follow Barry Jarrett's suggestion, and froth your way through five gallons of milk all at one time.
As is the case with most espresso machines, the steamer should be run for a few seconds prior to frothing to flush out the condensate. Once this is done, the steam is completely dry.
This is slightly more troublesome than with home machines. The polished stainless steel finish needs more TLC than the brushed or painted finishes. The water tank cannot be removed for cleaning when the machine is under an 18 inch counter; but it can be refilled easily. Descaling is a rather time consuming procedure, so I use a water softener (the Rancilio softener works fine, just take off one of the metal cross pieces/handles from the tank, to ease removal) and only intend to do it once or twice a year, rather than the monthly cleaning and descaling of the Solis. Instead, the brewhead needs to be backflushed about once a week.
IS IT WORTH IT?
Four caps and macs done in six minutes, and my friends wondering how the stuff they've drunk all their lives could even be called coffee. Two weeks to become completely spoiled by the no hassle operation. Yep, it's worth it.