# Aluminium exposure from an old aluminium boiler?



## FairRecycler (Sep 26, 2019)

I keep thinking of health risks of old aluminium boilers, where the adonised layer in place - to avoid aluminium exposure, widely used in the food industry - obviously faded out, due to calcification and/or probably due to the use of harsh chemicals to decalcify.

On most older boilers (pre 2015) the internal surface is not like on a new one, even after a good clean, so you can expect some aluminium exposure.

I was wondering not long ago. Would the coffee puck not filter out the majority of such contamination?
It would be interesting to measure aluminium content of water from a very old and very bad condition boiler and then the same but trough the coffee puck so the aluminium content of the espresso. I wouldn't be surprised on filtration effect above 80%, however this is only a guess.

Any experts here on the topic?


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## Agentb (Feb 11, 2017)

FairRecycler said:


> I was wondering not long ago. Would the coffee puck not filter out the majority of such contamination?


 I would think that would be a reasonable thought, most of the corrosion will be insoluble, and probably more will arrive in tap water if used than leached out of the boiler.

I had a quick search and found Corrosion properties of aluminium alloys and surface treated alloys in tap water

and Aluminum in Coffee focussing on Moka pot and a drip filter which might be interesting.

The amount of Aluminium in the coffee itself is going to muddy the water so to speak.

It would be interesting to know what alloys and treatments are used on these boilers.

Some hard water corrosion in that bottom photo! 😹


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## Ozzyjohn (May 31, 2020)

Thanks @Agentb- I've picked out an extract from the conclusions in the second linked document where they are brewing coffee in an aluminium Mokka pot - it seems to support the hypothesis put forward by @FairRecycler

" Interestingly, the Al content in the final beverage was lower compared to that of the brewing water, which points to ad/absorption processes in the ground coffee beans. We attribute this to the chelating and binding properties of proteins and humic substances in coffee powder."

An interesting topic, for sure.

Regards,
John


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## HDAV (Dec 28, 2012)

No expert but I grew up in a house with lead pipes..... 🤷‍♂️ Won't the aluminium oxidise rapidly ? Something I have wondered, aluminium is often used as a sacrificial anode in boat engines

is it ultra small particle that are the issue? Or the big chunky flakes of scale you find sitting in the bottom of the boiler.


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## Northern_Monkey (Sep 11, 2018)

@HDAV - I think most lead pipes have a passivated layer built up over the years as they would be pretty old even back in the day. The water companies used to and hopefully still do add in phosphate to help reduce lead issues.


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## HDAV (Dec 28, 2012)

Northern_Monkey said:


> @HDAV - I think most lead pipes have a passivated layer built up over the years as they would be pretty old even back in the day. The water companies used to and hopefully still do add in phosphate to help reduce lead issues.


 Isn't the same true for the alu boiler? A layer of oxide rapidly forms thus the aluminium doesn't contact the water directly ?

seems it's been discussed before

https://www.coffeeforums.co.uk/topic/23129-aliminium-boiler-should-i-be-worried/?do=embed


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## Northern_Monkey (Sep 11, 2018)

@HDAV - It does form a protective oxide layer, but the corrosion found in aluminium boilers and shower screen holders is much higher than I would expect for domestic lead water pipes.

Admittedly I have only sen a few lead water pipes in real life though. The descaling or acidic water does seem to give the aluminium parts a bit of a hammering.


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## HDAV (Dec 28, 2012)

Heavy pitting is one thing build up of scale another, I grew up in a hard water area now live in a soft water one the difference I. Kettles is huge


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## L&R (Mar 8, 2018)

A new Gaggia boiler doesn't have layers, coatings inside from factory, all you see when you open it after use is oxide layer.


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## FairRecycler (Sep 26, 2019)

@L&RR

I'm sure I read it somewhere (I'll try to find it later), these are anodised.


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## allikat (Jan 27, 2020)

FairRecycler said:


> @L&RR
> 
> I'm sure I read it somewhere (I'll try to find it later), these are anodised.


 Given there's no colouring , perhaps it's to ensure a consistent oxide layer over the entire boiler?


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## L&R (Mar 8, 2018)

yes, oxide layer saves aluminum to dissolve quickly into water.


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## MrShades (Jul 29, 2009)

In a world where McDonalds gets sued for selling hot cups of coffee that don't have an explicit "Warning: contains hot beverage" on them...
do you really think that Gaggia would still be selling aluminium boiler based machines all around the world today if there were any proven health issues with them? I don't.

Aluminium boiler health issues are a non-sorry as far as I'm concerned.

(Anyway it's essentially impossible to be in contact with pure aluminium)

Sent from my iPhone using Tapatalk


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## FairRecycler (Sep 26, 2019)

@MrShades This is exactly my point of view, however I've recently had the 3rd customer questioning the boiler material, due to concerns regarding to aluminium...

Probably worth to mention it's not only GAGGIA but pretty much every sub £500 machine has aluminium boiler.

On the other hand If I was given a tbsp of aluminium powder, matching the weight of the missing chips/holes of Classic boilers I've seen last year, I would say a definite NO to that.

I've started to dig into a brass boiler project, like the one on youtube, If I was to buy it from the chap, it would cost me around £190, identical volume with 1500W, but a lot more thermal mass, and bye-bye galvanic corrosion, no preheat installed. I cant see anyone would buy that TBF


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## Catlady101 (Sep 26, 2020)

apparently you can test for aluminium in solution by using a solution of ammonia ( no details given of concentrations) but from other googling the most common solution of ammonia is 1 Molar which is about 35g/litre which if my brain is still switched on is about a 3.5% ammonia solution.

you just take the samples and add some ammonia - the aluminium ions come out of the sample to create a white precipitate and I guess you eyeball the various samples side by side to see which has more white stuff in, as long as the ammonia solution stays the same concentration it might work?

I have to confess I do try and stay away from aluminium as best I can, my little Mokka is stainless steel etc, but I don;t think you can completely avoid it these days.


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## FairRecycler (Sep 26, 2019)

@Catlady101 It's quite difficult.

As per the study @Agentb shared above:

"Some foods that are naturally high in the total Al content include oats, potatoes, and spinach.4 A beverage that has been recognized for high concentrations of Al is tea."

"Regardless of the Al content in the raw beans, all of the subsequent production steps, postharvesting processes, storage, and packaging could enhance the metal concentration in the beans or ground coffee powder. Al has many different applications during postharvesting treatments, processing, and packing, including its use in airtight containers for transport or as easy-to-use capsules (CAPs). The Al content of the final beverage depends on several aspects: the Al content in the coffee beans, its water solubility, and the different brewing methods, during which the metal in brewing devices can partially dissolve."


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## csrti946 (Mar 26, 2019)

The Al link with Alzheimer's was disproven, well as much as anything can be disproven in observational studies. I would have to dig back to my undergrad days to find the guff. The debate with Al in cookware has been going on for a very long time...


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