Does the roast level of the beans you use effect the chemical back flush schedule? I have an ECM Synch and it allows you to set the clean cycle from 90-120 brews with a recommended at 100. I am using med-light to light beans. Will the less oily beans allow me to extend the cleaning cycle? Obviously cleaning with chemicals to often can wear out the seals but what is the risk of waiting to long between chemical flushes. As for water flushes, I do them every other day and make 2-4 drinks a day.

I don't know, but theoretically, a darker roast would seem like it would warrant more frequent detergent backflushes as there is more oily residue that could get left behind.

Too much detergent can be harder on the cams/lube in the machine over time, so I use BioCaf (not the harsher cafiza) and take a less is more approach to backflushing. I have an ECM Synchronika and use medium-light beans as well. I have found BioCaf detergent backflushing roughly every 2.5-3 months / 200-250 shots / 4kg-5kg coffee to be sufficient. I don't see much gunk come out even then. However, I do a water backflush daily (and usually after each shot or sequence of shots).

For an e61 machine like the ECM Synchronika, detergent backflushing is most important for taste, not breaking the machine (though I suppose if you went way too long it would gunk things up). From a mechanical care perspective, my understanding is that choosing to detergent backflush every 100 shots is not different than every 250 shots. The choice has to do with taste. If I am not mistaken, I believe that for some styles of machines (non e61), the detergent backflush schedule is more important to prevent machine damage via residue buildup on solenoid valves in the grouphead. I don't think that is a concern for us. For our Synchronika's, I think it is ok to choose your backflush schedule (i.e. once a month vs once a quarter, assuming avg of 2 double shots a day) based on taste, not fear of damaging anything.

I would think for your 2-4 shots a day with medium-light roast, a detergent backflush every 2 months/200-240 shots would be ok. Note that if you are water backflushing or running the brewhead to clean out the portafilter, the ECM shot timer is semi useless as it will accelerate the shot counter. I wish the shot counter for cleaning only registered if it was used for ~20 seconds or more.

Would be curious to hear other's input on this topic as well!

Interesting, I knew taste was one of the reasons to use a detergent but I thought the main reason was to ensure everything stayed clean and running smoothly. As for your point about the brew counter being semi pointless, the manual states that only brews over 15 seconds add to the count so backflushing and cleaning the brew head only adds to that if its over the 15 second threshold. Most of my back flushing is in the 10 second range so for me this isnt a problem.

I may be new to the E61 only owning my Synchronika a couple weeks now, but the brew path is pretty simple. Worst case it shouldn't be too bad to take it apart to clean. Currently i do a water back flush daily. In a couple months I'll do cafiza. Should be pretty easy to tell if your schedule is good or not. If you do a chemical flush and get a ton of crap out, you could probably do it more frequently. If it's totally clean, then not much point.

Those of you who are doing frequent water backflushes, are you using the portafilter cup and how many cycles do you do?

To do a proper water back flush you use the blank/cleaning basket. That enables it to build up full pressure and flush the system, if you do it with a standard basket you are only going to get a small amount of pressure pushing thru the system.

As for the darker roast being oiler, all I know is that on darker roast there is always more oil in the basket after I pull a shot compared to a lighter roast. I am not sure if the roasting process breaks down the bean creating more oil or what, but the darker it is the more oil I see.