La Pavoni Europiccola rust and bad tasting coffee

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Salcoffee

#1: Post by Salcoffee »

Hi,
Is it normal to have rust inside the boiler of Europiccola. Mine is rusted. The rust does not seem to leech into the water as I took a cotton swab and rubbed it inside and no rust came onto the swab. But my Europiccola has been brewing harsh bad tasting coffee for some time. I had the machine since 2011 and it is used on average at least 3-4 times per week. I think it's the rust that's contributing to the bad taste. Any thoughts?
...BTW I use a Vario grinder, I clean it regularly with Grindz, I descale the machine with Dezcal. I've used a variety of coffee from local roasters to brand names, I do have my favorite Miscela d'oro but the last bag I bought still to my dismay made a bad brew. Thanks.

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rpavlis

#2: Post by rpavlis »

The boiler and all the normal things inside are all brass and copper. The only way there could be rust in the boiler is for a steel object to have somehow gotten into it. I have an old 1978 La Pavoni. When I first got it, it kept getting rust inside. I discovered somehow someone had dropped an M6 nut into the boiler. In contact with the water and the more noble metal, copper, the nut underwent rapid electrolytic corrosion and the water looked almost like orange juice after a very short time from the suspended iron oxide. Once I noticed the problem and removed the ordinary steel nut the problem instantly went away.

You could have bad ring seals. This can look like rust, and there can be particles of coffee that get into the boiler this way that might look like rust particles. When you have bad seals usually when you first push down the lever it will give a bit as the small amount of air trapped below the piston is squeezed through the seals. Water is more viscose, so you can complete the pull, but some brewed coffee and possibly small particles can get past the piston and from there on to the boiler. Deposits will form in the boiler from this that can taste bad.

I did not notice this once until there were substantial coffee deposits. I first changed the piston seals. Then I drained the boiler thoroughly, rinsed it with a bit of 190 proof alcohol. (From rum shop.) Then I put in about 50mL or so more 190 proof alcohol and shook the boiler around tipping it at every angle, and then I drained it out. I repeated the process, drained it thoroughly, and then rinsed out the boiler with tap water several times. Finally I filled the boiler with my standard brew water, about 1.0 mM potassium bicarbonate in distilled water.

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Salcoffee (original poster)

#3: Post by Salcoffee (original poster) »

Thanks for the reply. Maybe it is the seals, like you said i do get some "air" when I first start my pull, which I pull the lever back up again to eliminate the air so I can start my pull with full pressure from the start. But my machine was new when I bought it and no other nuts besides the factory ones are in the boiler.
But generally speaking, for everyone else, is rust normal on these machines? Can I order a new boiler from the factory to replace mine? Or not to worry.

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rpavlis

#4: Post by rpavlis »

It really cannot be rust, because rust only can form from iron! Thus rust is certainly not normal! (But rust could be from iron in the water, but that much iron in water would make it taste bad when drunk.) Copper and brass are inert things for the most part unless in contact with certain things. (Like high concentrations of salt.) Cupric oxide is black, cuprous oxide is reddish, neither copper oxide really matches the colour of rust.

It is easy to disassemble these groups. I can have mine in pieces, cleaned, and put back together in about 15 minutes. I have timed doing it. (Though there is a learning curve to do this.) Were you to disassemble it, you could check for severe build up of "gunk" inside, and you could check the condition of the seals. I tried to get a digital image of a bad seal, but the image did not show the problem very well. The healthy seal is smooth all the way across the surface that contacts the walls of the group or cylinder liner. Bad ones have a sort of "fold" in them along the contact surface. I would advise removing the pins and handle and the acorn nut and locking nut on the piston rod before removing the group from the boiler. (There is a special tool that makes removing and replacing the pin clips easier. These tools come in two types, one for internal clips and another for external ones.) I replaced the pins on mine with brass rods that I threaded on the ends and put acorn nuts on them to make servicing easier and for cosmetic effect.

Many are shocked the first time they disassemble a group from almost any espresso machine by the deposits and "gunk" inside.

Salcoffee (original poster)

#5: Post by Salcoffee (original poster) »

Thanks,
BTW, is the inside of your boiler brown/red looking?

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rpavlis

#6: Post by rpavlis »

The inside of a boiler that uses water that does not scale gets a coating of CuO mostly, which is dark brown and is just a thin layer. This is very impervious and forms fairly quickly and is stable.

By the way, you could also be having problems with the polyphenylsulphide cylinder liner. They eventually fail. You can tell this also by disassembly of the group.

Salcoffee (original poster)

#7: Post by Salcoffee (original poster) »

Thanks,
I took another look inside the boiler, it's reddish in color which at first glance one would assume to be rust. But I rubbed my finger on the inside wall, and the surface is smooth, even the bolt holding the sight glass looks rusted but it's smooth and not rough and the color did not rub onto my finger like rust would have. As you say then it's a coating of CuO. I let the water cool and poured it into a pitcher. The water was clear and it tasted clean. I think I do need to replace the gasket, since I'm getting very little creama? I'm hoping to get my machine like before, I was pulling some amazing shots....it's been a long while...I'm not giving up on these levers'
I like to get other owners of the Europiccola response on the color of the inside of their boiler. Thanks everyone.

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Salcoffee (original poster)

#8: Post by Salcoffee (original poster) »

I think there's another reason for the bad taste. The grouphead may be too hot. I have a pressure state that reads 1.0 bar. Is that the factory setting? Would lowering it produce better coffee?

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drgary
Team HB

#9: Post by drgary »

Lack of crema can come from grinding too fine.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

Salcoffee (original poster)

#10: Post by Salcoffee (original poster) »

Thanks Gary,
Maybe the grids are too fine. I'll look into that.