I purchased an ECM Technika IV a few months ago and I knew that it would take a little time to adjust to compared to my Valentina. Both are HX machines, but the ECM is reputed to require a much smaller cooling flush. I noticed this immediately because the best shots I got required no cooling flush. I also found that the best shots were the first one's I pulled after the machine had idled for a long time. Shots in general were inconsistent and I chalked this up to a learning curve with the new machine.
I tried to dial it in. The brew pressure was set at almost 11 bar, so I backed that down to 9 bar. Strangely, this seemed to make things worse. Now shots were definitely sour and seemed underextracted. So I tried different coffees and different roasts (darker roasts were better than lighter roasts). I played around a lot with grind, dose, and tamp to try to improve the extraction. I put it on a timer to give it a full hour and half to warm up and I even bought a new grinder. All to little or no avail. I was starting to think I was just a total suck ass barista.
With nothing else left to try I decided to adjust the pressurestat from the factory set 1.25 bars and increased it to 1.35 bar. Things were definitely better, but shots (especially any after the first) were still sour and the crema seemed thin despite using fresh coffee. This is when it dawned on me that it must be a temperature issue. I contacted the dealer and the manufacturer to find out what to do about this problem. They said it's not the machine, it's your grinder, it's your dosing, it's your coffee, etc. Ugh, very frustrated but still convinced that the machine has a temperature problem. So I rigged up my thermocouple and threaded the wire into a portafilter basket. The temperature readings were definitely low, but I couldn't be sure that this wasn't due to bias in the measurement technique.
Contacted the dealer again who says the problem could be scale buildup and suggests that I descale the machine. I explain that the machine is only a few months old and that I use a whole house water softener and I've measured my water and it is very soft. I seldom descaled my old machine and never had any scale issues with it. But I descale it and it makes no difference.
Finally, I ordered Eric's thermometer from CC to definitively test the temperature. Got the thermometer installed and fired up the machine. Bingo! The idle temp after 2 hours only gets up to 185 F. I contact the dealer again and they question the calibration of the thermometer and insist I test it in boiling water. I test it and and it reads 212 F.
The dealer and manufacturer have me check a few other things - different GFI outlet, OPV, etc - and nothing works. I contact Eric, the thermometer manufacturer and HB temperature and pressure guru, and explain the problem and he says it's something in the thermosyphon loop. So I go back to the dealer and manufacturer and they have me inspect the thermosyphon tubes. I disassemble and find no blockage. Eric emails me to say "make sure to check the HX". So I remove the elbow fitting from the top of the HX and voila! There is the problem. When the machine was assembled the upper teflon tube in the HX was a few mm too long and made contact with the lower copper tube which caused it to deform and partially close off the thermosyphon.
The rest of the repair was pretty straightforward. Cut a few mm off the teflon tube at a 45 degree angle per the manufacturer's instructions. Reassemble the machine, start it up, and it quickly gets up to full temperature. Problem finally solved.
It's a strange problem so I thought it might be of interest to HBers. But more importantly I learned a few lessons in this process:
- 1. Sometimes it's not your technique, it's the equipment.
- 2. Fully test out a new machine as soon as you get it, including the temperature (and buy Eric's thermometer!).
- 3. Be relentless in following up with the dealer and manufacturer about a problem, but also realize that you can probably get better insights from the many knowledgeable people on HB.
- 4. Use the blue heavy duty teflon tape called MegaTape available at Home Depot. It's much better than the thin white stuff for sealing threads on boiler fittings.
- 5. The ECM Technika does NOT have a thermosyphon restrictor. It has a tuned HX where the longer length of the tubes inside the HX moderates the thermosyphon and pushes more cool water through when a shot is pulled.
- 6. You can waste a lot of coffee and time trying to figure out a machine problem.
- 7. Espresso is awesome when properly extracted, but otherwise can really suck.
- 8. Finally, and most importantly, Eric is an espresso rock star!! Listen to what he says.