Older portafilters with internal brass exposed and taste

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#1: Post by redbone »

Lousy title I know. I'm wondering if others have this issue or is it just me.

Some of my older machines have chrome over brass portafilters. These P.F. now have exposed brass on the inside where it appears the chrome has come off over the decades. As much as I've cleaned and soaked them, I find the brass imparts an off smell and taste. Some worse than others.
My previous Zacconi was so bad that I had the bottom cut and essentially made it into a bottomless portafilter. The Faemina although has a smell up close it does not seem to impart to much to the cup.
I'm reluctant to rechrome the P.F. as I'm not sure of Cadmium exposure or have another food safe sealing process done like dlc, as Some forms have been certified in the EU for food service. https://en.wikipedia.org/wiki/Diamond-like_carbon

Fairly recently I replaced a vintage LaPavEuro P.F. with a stainless steel one from Cafelat, partly due to a similar issue and never looked back.
I found the S.S. easy to clean, imparting not smell or taste in the cup. Although an argument can be made this is new, it does not have any layers of another metal on top that may come off and is a harder metal than brass.

Most of my vintage levers boiler are made of brass but found straight water (no coffee) contact does not impart a taste or smell issue once the brass is seasoned and sealed. Issue seems to happen with coffee to brass contact. Maybe due to coffee PH or properties within hot coffee causing leaching.
Anyone else found this exposed brass on portafilters to be an issue and if so found a reasonable solution ?
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#2: Post by Marcelnl »

I always thought my original faemina pf inside was never chromed, but am now using a SS bottomless version from Francesco for a while. I never thought the exposed metal on the inside affected taste, the dwell time would make that hard IMO if the PF had been exposed to coffee for decades any metal coming out of the surface layer would long have leached almost completely...I'm also not sure how fast chrome is removed by espresso without any abrasion, my guess is that it takes ages for real good chrome layer to be removed, just looking at the drip tray that is still chromed and is much more exposed to abrasion by cups.
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#3: Post by jwCrema »

Even new portafilters are chrome over brass based on what I have purchased over the last five years. I have a new Cremina pf that is showing some brass now. It took about 2 years to expose brass on ECM and Cremina pf's, without using an abrasive cleaner for both. I was very surprised.

I am also using a ss bottomless pf now, only because it's really easy to keep clean. I can't detect a taste difference when the brass is kept clean.

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#4: Post by civ »

redbone wrote: ... wondering if others have this issue or is it just me.
... much as I've cleaned and soaked them, I find the brass imparts an off smell and taste.
I myself have a Cimbali Junior D/1 (ca. 2000) and a couple of EPs.
All have PFs with brass showing (100% in the EPs) and I have never noticed (ever) any strange smell or taste.
I keep the PFs regularly clean with a scotch brite type pad.



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#5: Post by samuellaw178 »

While we're on this topic - has anyone ever sent the brass in pf for lab analysis? Is there the slightest hint of lead in there, or other potential brass additive? That seems to be another major concern other than the also-very-important taste aspect.

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#6: Post by aecletec »

I was thinking... you could get the gub'ment to test it for you... boil a portafilter in water for a bit? ;P
http://www.measurement.gov.au/Services/ ... ticUse.pdf

The corrosive aspect of coffee is a factor... but so is the tendency for it to coat a surface and perhaps isolate it from the rest of the solvent...


#7: Post by erik82 »

The chrome flakes coming off of your portafilter are also a risk. E-61's are also brass with a chrome finish and they tend to lose some of that finish too during years of use.

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#8: Post by HB »

I've removed some off-topic posts and put this thread on a short cooldown.
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#9: Post by sweaner » replying to HB »

Oh, come on Dan, my picture was funny and tragic at the same time!
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#10: Post by rpavlis »

Brass is a bronze type alloy that contains copper and zinc. Machinable brass contains some lead. When brass is machined the surface tends to accumulate lead--it is added to lubricate the chips as they are removed to prevent their sticking to the tool and work piece. There is a standard technique for removing this lead and many other surface contaminants that involves using concentrated acetic acid and 30% hydrogen peroxide.

These are somewhat nasty materials. Instead you can use standard house hold white vinegar mixed with 3% hydrogen peroxide. White vinegar is typically somewhat over 1.0 M acetic acid, usually about 5 to 6%. Mixing vinegar and 3% hydrogen peroxide at a ratio of 2 parts vinegar to 1 part 3% hydrogen peroxide works well. When I machine brass parts that are to contact food or drink, I use this. You should have the part very very clean and polished first, and immerse it for about 15 minutes, at least 10. Be sure there are no machining oils on the part. The object will look beautiful after this treatment until the surface oxidises.

Rinse the object with plenty of water after this. I normally put a gram or so of one of the potassium or sodium phosphates into about 100 mL of water, and dip the object in that for a few more minutes, and then rinse again very thoroughly. Do NOT dry the surfaces that will touch food or drink with anything that is abrasive, even polishing compounds after these treatments. Most metal phosphates are extremely insoluble and tend to coat the brass surface and protect it from external things.

Take care NOT to allow strongly acidic things to be in contact with brass or copper things.

I have used about 50 to 100 mg/litre of potassium bicarbonate for brew water for years. This produces no scale at all, even after constant use of the machine for years. That means no descaling, which always draws all sorts of things into solution and removes protective layers from parts. Relying on the bicarbonate in hard water tends to give erratic bicarbonate concentration because the scale formation removes much of the bicarbonate from the water. You can use sodium bicarbonate too, but to me it tends to give a slight brackish taste, that may not be a negative for many other people. Coffee beans contain massive concentrations of potassium, magnesium, and calcium. (Especially potassium.)

Perhaps your water is not alkaline enough. A big advantage of mixing brew water this way is that one can control exactly what one has!!!

Furthermore avoid water with chloride. Copper and many other metals form complexes with it.