jmc wrote:Where did you get this from ? Commercial E61 machines are detergent " blasted " every night and yet last for years.

Commercial machines are usually regularly serviced, often by a tech who arrives with a box of parts. The seals and the internal brass "followers" that ride on the cam in an E-61 are easily and quickly replaced- probably no more than 15 minutes per group if the tech is holding a cigarette in one hand ("Misses Rasmussen's Book of One Armed Espresso Repair"?). The total number of tools and parts needed for that can be carried in a very small toolbox. Balanced against the amount of use that a commercial machine gets daily without being backflushed, the detergent cleaner is necessary at the end of the day, or even multiple times a day. In a lot of coffee shops, machines don't even get looked at until they don't work or smoke comes out of the cup-warming tray.

Commercial E61 machines are detergent "blasted" every night and yet last for years.

The commercial E-61 machines (or similar) used in most US espresso bars ARE NOT lever E-61's but rather are fitted with solenoid powered 3-way valves. I base this statement on a real good knowledgebase of what specific machines are installed in the Washington DC area coffee bars.

Certainly, machine installations in Australia may be different but you also need to agree that those coffee bars in your country equipped with lever E-61's very rapidly "reload" coffee oils onto the mechanisms.

Yep an E61 is not an E61...

The manual lever type has a different process for managing the release of preasure and if one was to be blasting all the time with a chemical cleaner, seals and cams would be high on the maintenance list.

I have also worked on some that were almost choked, regardless of so called cleaning. The fix by the user was to just keep going coarser on the grind... When it would not longer work, they called me and I even got them to show me how they cleaned..

Nearly 2.5 years in a little cafe that does 30 to 50 kg a week, and never had the shower screens off or changed a seal and for two groups, even the baskets had not been removed. Soaked weekly but never disassembled.

A manual clean and new seals and it was all running again. They were actually looking to dump and to get a new machine. As had been told it was teh pump and scaled up boiler, thus too expensive to repair...

But they did what they thought; was weekly maintenance

earlgrey_44 wrote:I think I'll experiment a little...

Did I experiment? Well, not exactly, but I did do some systematic observations in the fall to see if I was keeping the water tasting good. I also did some parts inspection to judge the wear rate on the cam followers inside the E-61.

After a descale, I started drawing water from the grouphead after all my cleaning steps were done and the machine was ready for brewing. I let the water cool and noted its taste. I did this every week for two months. Here's six weeks of results:




After a descale, the water tastes noticeably metallic for a while. No surprise there. The coffee tastes seemingly nicer to me than before the descale if anything, so the metallic taste doesn't seem to intrude on the cup.

I had normally done a detergent clean monthly, but here and subsequently, I've done it a little more often. The flavor of the water, with my usage rate and cleaning routine, starts getting noticeably funkified in the third week after a detergent cleaning.

Does this deterioration of the water taste affect the cup flavor? I really don't know, but it offends my culinary sensibilities to make coffee with water that has an off flavor, so there I am. It seems that something like a three week rotation for detergent looks good to me at this point.

I looked inside the E-61 after the Descale to see how the valves were doing.

This unfortunately rather lousy photo shows what I found:



The flats at the end of the cam follower pins have been slightly dished, with the dishing extending over maybe 80% of the flats surface. As the pics show, the beveled corners are still untouched.

This is after two years, nine months of daily light use, as the consumption shown on the table during the taste tests is typical for me. I didn't start doing my semi-annual lube of the cam until about half way into this usage period.

Am I going to step up the lube activity since I'm already using more detergent? Probably not. The wear problem doesn't seem to be that big a deal. As has been wisely pointed out, the more you mess with the machine the more potential for trouble you risk too. Specifically, the more I stick my big steel wrench into my machines face, the more opportunity there is for a moments inattention to allow a big ding in the grouphead to happen. You need a good reason to disassemble a showpiece item especially.

So my cleaning approach is tweaked to clean a little more often with detergent than where I was before, guided by the criteria of maintaining a decently neutral water flavor. The only thing I don't like about it is that it's hard to remember to do anything every three weeks...

Considering the trivial cost of pins and a cam
Why produce and drink coffee with Dow Corning 111 as a flavour enhancer ?