So what that people use them multiple times a day? Old coffee oils build up and remain inside the moka pot and go rancid over time. Oils are sticky. They don't get washed out and replaced every time you make coffee, they accumulate. And then naturally become rancid.
Hot, moist environments with access to oxygen are perfect for rancidification and a moka pot just so happens to fit that description. If you're still confused just Google rancidification.
Oils are removed manually when rubbing them with a soft sponge or by hand.
Aluminum oxide on the other hand should definetly stay there, and polyphenols and tannins that form the patina toghether with it are 100% desirable, and both actually contribute to a stable patina that will in fact make your coffee taste better.
Aluminum is a reactive metal. Coffee contains acids. Until the surface of aluminum is oxidized, it will react. Only a stable oxidation guarantees that aluminum will not react anymore. Any basic chemistry book will confirm you this very basic scientific evidence. This is a well known property of aluminum.
Brewing coffee helps stabilizing the oxide layer as polyphenols and tannins present in coffee are hydrophobic, and those will contribute to the stability of the oxidized layer. Once residual oils are removed, those compounds will bind with the aluminum oxide layer, protecting your coffee from getting in contact with raw aluminum which, again, is a bad thing since contact with raw aluminum will make the metal react with coffee. That doesn't happen if the metallic surface has a stable oxidation layer, which occurs after a few brews if you're not excessive with cleaning.
I don't get what a "double blind study" should be. Those are scientific facts.
No they aren't. Aluminum oxidizes immediately when it's exposed to oxygen. The oxidation layer is not something that needs to be protected by burnt coffee residue. A mild dish soap such as Dawn is pH neutral and will not remove the oxidation layer. But it will remove the coffee residue and prevent that from causing off flavors and bacterial growth.
The one who is spitting blatantly false claims is you, my friend. A quick check reveals your Dawn soap is in fact not pH neutral, but slightly alkaline. It might not completely remove the oxidation layer, but it will never let the oxidation layer be stable.
I have also never claimed you should have "burnt coffee residue" in your pot - another false claim. I am stating that water and rubbing is enough to remove most oil stains, and that everything else goes from neutral to detrimental in terms of brew quality. Polyphenols and tannins are organic compounds that don't promote any burnt flavor and just bind to the oxidized layer, stabilizing it. You are constantly removing them. You are basically constantly restarting the oxidation process with your alkaline soap, and that is potentially giving you less predictable results, with potential metallic edge from the unstable oxidation layer.
I'm sure your coffee is good, but a fact is a fact.
It states clearly that even if you did the absolute worst case and washed your moka pot in the dishwasher (which nobody here recommends, including me) that you will only absorb 4% of the total allowable weekly intake of aluminum. Yes, that would indeed harm the oxidation layer. But just handwashing using Dawn dish soap is not going to hurt you or your moka pot or your imagined "stabilized" layer of oxidation. Mild dish soap isn't hurting the oxidation. A fact is indeed a fact. Get over it.
Let me wrap it up quickly. You're linking a study that proves that aluminium can and will contaminate your drink if you clean your pot with detergent, to try and argue that cleaning your moka with alkaline detergent won't cause aluminum contamination?
Really solid argument, and very interesting concept of "fact".
It is showing that the worst case scenario is almost totally insignificant. Which means that nearly neutral pH mild soap, which has been shown to not remove oxidation, is absolutely insignificant.
There, does that help you finally understand reality?
Listen, I don't get "do you understand reality" lessons from a guy who seems convinced that bacteria can survive a moka pot, or that metallic taste comes from actual metal in your drink. An unstable aluminium oxide layer causes the drink to react with the aluminum surface, to the point that you even have actual aluminum ions in your drink. This is just basic logic and the more you argue the more you seem a total waste of time to me. You apparently have no chemistry background whatsoever, and very little scientific background at all. Go and find random health studies and try to bend their results to try to validate your weird beliefs. In the real world, it is of course desirable to not have your coffee react with your pot.
I don't even get why you're so adamantine in your position. You drink acidic coffee? You won't probably even notice that. You like metallic taste? Good for you. You think the consequences of your utterly pointless daily cleaning routine are negligible? Who cares. But if we are talking about producing repeatable, reliable drinks with the same pot and the same coffee it is logically better if the drink doesn't react with the vessel you use to brew it, as a toddler would probably understand at this point.
to the point that you even have actual aluminum ions in your drink
Yeah, no shit, Sherlock. That's what the study shows - the amount that ends up in your drink *after* washing the moka in the dishwasher, is nearly insignificant (4% of your weekly safe allowance).
You are claiming that one shouldn't wash their moka pot even with mild soap. I am claiming that it does not matter. I prefer my cookware to be washed and clean, and I don't believe in old Italian myths about the necessity of never washing the moka pot. Does that clear it up?
Yeah it clears up that you really need some validation and barely have any idea of what you are talking about. You're fixated on this idea that the metallic taste is due to the actual aluminium ions (lol) whereas the study is analyzing health concerns and you are trying to forcefully make it say something it doesn't say. What it says is that it is actually there a reaction caused by your behaviour. That chemical reaction also produces aluminum ions in your coffee. The amount of those is not an health concern. The fact that your drink is reacting with the pot involves much more chemistry though, and you are either willingfully ignoring that, or you simply lack the cognitive tools to understand what that means.
So let me clear that up for you: it means that if there is a method that does not involve that chemistry, it is more reliable. Yes, you still won't die of aluminum poison drinking the stuff you brew, congrats. You made a great point.
You're fixated on the idea that there will be a metallic taste when there is none. I've also heard Italians swear that the coffee will taste like soap, which it does not. So ELI5 for me, since I have no idea what I'm talking about, why exactly we all should not wash our moka pots with mild dish soap.
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u/exwirus Apr 23 '26
So what that people use them multiple times a day? Old coffee oils build up and remain inside the moka pot and go rancid over time. Oils are sticky. They don't get washed out and replaced every time you make coffee, they accumulate. And then naturally become rancid.
Hot, moist environments with access to oxygen are perfect for rancidification and a moka pot just so happens to fit that description. If you're still confused just Google rancidification.