Yes, I soaked it in Cafiza too. This is what the last piece looked like before:

I removed my 2-1/2 year old Duetto's mushroom for the first time just now. I have been running it on pretty gross hard water a lot, but I descale on a somewhat regular basis, and recently switched to filtered water. The mushroom is not scaled at all, and the chrome is actually mostly intact. However, it has got a lot of clumps of some sort of brown particulate on it, especially at the top. I also noticed the same gunk at the bottom of the mushroom chamber, and in the cam chamber. It kind of looks like metal shavings. Is this... bad?

I opened the brew path and poured water into the mushroom chamber, and it all came out into the drip tray. It's sitting on the bottom and there seems to be a lot of metal particles. I assume some of it is chrome that came off the mushroom. Is it normal to have that kind of crud inside the group?

My main purpose for servicing the group was to lube the cam and pins. I added a spot of Dow Corning 111 on all the surfaces and it now glides like you wouldn't believe. Absolutely worth a few minutes to lubricate now and then.

After flushing out the clumps of particulate, I re-assembled the mushroom, turned the machine on, and discovered the pump ran but not a drop of water came out of the group. A quick Google search and I realized the tiny exit hole in the upper part of the mushroom must be blocked. Opened it back up and there was indeed a little clump of the same material stuck right over it. Fished it out and now the machine runs beautifully.

I have a measuring cup full of all the water and metal bits I flushed out of the group. There is a tiny bit of scale, but most of it is obviously copper-colour metal particles. I've backflushed a couple times, and I'm still getting stuff coming from the three-way valve, as well as a small amount in the blank basket. I guess it should clear up once everything I dislodged gets flushed out. Is it normal to find this sort of thing in an unserviced E61 group?

In this thread, I posted this pic of a descaling kit I was developing -

Degraded espresso machine performance OR "The Scale Monster Attacks!"



You are much better off by leaving the mushoom out of the group and replacing it with an expanding plug and spacer. The expanding plug in SS is available from McMaster-Carr and the spacer is homemade from PVC pipe. There's probably more than a few of those particles still lodged behind the dispersion screen.

nixter wrote:I have had my Giotto evo for almost a year now so I think it's time to check for scale. My tap water is some of the softest around (0.3 grains per gallon) I couldn't find a lower number in North America. Even so I run all my water through a Brita. Is the condition of the mushroom enough of an indicator of scale? If my mushroom looks clean should I just leave it another year?

Your water might be 'too' soft - for an experiment you might try a little harder water to see if your espresso tastes any different. A tank or two of harder water isn't going to bother your machine.

BTW - 6 years ago I covered this in Sputtering e61 & HX scale build-up - Cured! a topic where my brew water wasn't even getting close to proper brew temps. There was so much scale in my system I figured that it was insulating the HX loop preventing the brew water from heating. Check that thread out for some extreme 'mushroom scale porn'...


Note the shiney new chrome plating. That was wiped out after I detergent backflushed right after descaling the machine. I had flakes of chrome for 3 months coming out of the gh. I recommend spacing out descaling and backflushing by some time....

Here's my contribution:

Comments are welcomed.

Clearly, mine looks very different! The lovely soft green stuff looks to have a lot of copper carbonate. In particular, I wonder about the ratio of corrosion product to scale here. This reflects 6 months (first pass at a descaling interval) of daily use in medium-soft water. The screen had a little gray-green slurry on it, but the chamber and thermosiphon ports were pretty clean. Cleanup revealed that each of the green blobs covered a spot where corrosion of the underlying brass had lifted a flake of the nickel plate.