Can Stainless Steel Affect the Flavor of Coffee?

Does stainless steel affect the flavor of coffee?

Coffee makers are quite often made of stainless steel, especially the small espresso makers. Although most mugs and cups for drinking coffee are made of china, porcelain or paper, stainless steel is sometimes preferred for cups which need to have a lid put on them or cleaned in a particular manner. Although stainless steel has many benefits in that it is extremely durable, tough and easy to clean, many coffee drinkers feel that the use of stainless steel either in the coffee maker or the drinking cup can adversely affect the flavor of the coffee. But is there any truth in this?

From a scientific point of view, stainless steel cannot affect the flavor of the coffee. Steel is a stable and inert compound, and even when formed into a cylinder such as a mug and filled with boiling hot liquid, there are no chemical reactions going on which could mean that the flavor of the coffee is altered. It does not start to break down or corrode, which is exactly why it is such a popular choice for professional kitchens and for environments where hygiene and cleanliness are essential.

However, that’s not the whole story. Steel is porous just like other materials such as plastic or glass used for coffee pots, and china or paper used for cups. This means that tiny particles of oils from fingers or mouths can seep into the surface of the steel and even a thorough cleaning regime won’t remove them. Over time, these oils and other tiny particles start to rot down and when they come into contact with a hot liquid they pass back into it and affect the flavor. This is obviously much more of an issue when dealing with stainless steel coffee mugs than with makers, as the mugs have much more contact with fingers and mouths. To minimize the effects of the stainless steel on the flavor of the coffee, it’s important to ensure that mugs are rinsed out well using hot, soapy water after use. If any sort of build up or residue is noticed on the inside of the cup, this can easily be remedied by filling the mug with household vinegar and leaving it to soak overnight, before rinsing it out. There are special products available which do the same job, but they are often full of harsh chemicals and best avoided for things you are going to drink from afterwards.

When talking about stainless steel coffee mugs, these are usually used for situations such as travel or when working in an environment where it is essential liquids are not spilled or mugs are not easily broken. Lids on the mugs are designed to be tight fitting to avoid drips or spills and as a consequence this cuts off the aroma of the coffee. Smell is a massive part of taste, and not being able to smell the coffee inside the cup can lead many to believe that the flavor has been affected by the container.

33 thoughts on “Can Stainless Steel Affect the Flavor of Coffee?”

  1. Calaverasgrande

    I disagree.
    I have had stainless coffee mugs that are brand new. Only been washed with hot water.
    They made the coffee taste terrible.
    Then I washed them with soap.
    And the coffee tasted terrible.
    After a year of use the coffee tasted terrible in exactly the same way.
    It doesn’t taste like old coffee. It doesn’t taste like cheap coffee. It makes the expensive $20 lb coffee taste like convenience store coffee.

    I do not know chemistry. But something is going on.
    I certainly did not psychosomaticly imagine the coffee to taste bad.
    I spent $50 on that mug/thermos. I expected it to make my coffee taste better!

    1. I completely agree. My wife and I have run informal experiments where we use clean, new stainless mugs (lidless, so as not to affect aroma) and even quality coffee roasted the day before tastes flat and cheap compared to an identical pourover in a ceramic mug.

    2. I completely agree with you. The better the coffee the worst it tastes. Perhaps, the higher acid of lightly roasted coffees. Science and my taste buds do not jive here.

    3. You are correct in assuming that there is no scientific research behind the science claims made in this article. In fact this article is a dangerous lie. The fact of the matter is that coffee is acidic and causes and acidic foods cause an unhealthy reaction with stainless steel and other metals. Here’s some actual science behind the matter;

  2. I agree and so do many others I have had this discussion with. There is something to this…… I now only use ceramic travel mugs! Cheers!

  3. Something surely is amiss. I bought an expensive stainless steel coffee maker and the coffee tasted like the metal carafe even after cleaning it thoroughly. Not sure what else to do to get my coffee to taste like coffee. Any suggestions?

  4. Stainless steel does make my coffee taste not as good…to the point where I don’t enjoy it so I don’t even bother taking it to go anymore. I ordered a ceramic travel mug but go figure, it broke in the mail! Anyways, I’m glad to see I’m not the only one who thinks it makes the coffee taste differently. I brew organic coffee at home, but with the stainless steel I’d rather just pick up a coffee at Dunkin Donuts or somewhere while I’m out.

  5. I just purchased some very expensive 20oz mugs for coffee and 30oz for cold beverages, I also bought stainless steel straws. I can attest the flavor is definitely altered, I but flavored coffee and I thought maybe I got a bad batch! But I put the coffee in a ceramic cup and the flavor comes through just fine! Same goes for soda it just tastes different. I’m wondering… I have silver fillings and some gold caps
    ( I don’t due well with porcelain ) in my mouth, could there be a reaction going on ???

  6. I agree, something is amiss, clean or not my SS mugs always make coffee taste worse than my ceramic mugs at home, and I wash them both the same way. I just found that Bubba now sells a ceramic-lined, fully stainless steel, vacuum insulated travel mug with no exposed ceramic on the outside to break. Honestly this makes my coffee on the go taste better. It’s pricey at $20 though. I picked a couple up at WalMart. This is the best idea ever, worth the premium. Now, how do I make coffee into something not lined with SS that’s still insulated?

  7. I noticed my coffee was less flavorful in some travel mugs but not others (all lidded) and after some investigation came to the conclusion that only the stainless steel, and not the plastic mugs affected the richness and fullness of the flavor. I would still use my trusty leak-proof travel mug accepting the trade-off of flavor for dry carry-all bags. When my coffee maker broke down I got one with all the right things: right temperature water and a sprinkler style water pouring head. The coffee was mediocre even though I was using the same beans as in my old maker. The basket for holding the paper filter was stainless steel. I switched it out with a ceramic cone on top of my coffee mug in place of the metal basket and glass carafe and was rewarded with an excellent rich and flavorful cup of coffee.

    Remember that “non-reactive” refers to how a food will affect the finish of a pan. Acidic foods will interact with and essentially dissolve some metals, and when those metals are found in cookware the finish will be affected by the food. What seems to be going on here is that the stainless steel is not begin affected by the coffee (it is non-reactive) but the coffee is being affected by something in the metal. If I had to give an educated guess (I made it through Organic Chemistry in college) I would suggest that ceramic, which is used as an electrical insulator, is carrying no charge and has no / little reaction with the coffee. Stainless steel, however, is a good conductor and thus by definition has a few easily liberated ions floating around. It makes sense that the acidity of the coffee is indeed interacting with the ions of the stainless steel that simply are not available in ceramic.

    Any researchers out there looking for an easy experiment?

  8. Exactly, try drinking orange juice (high acidity) from a stainless steel bottle and see if it doesn’t taste ‘metallicy’… Stainless will affect flavor no matter how hard you clean it out.

  9. Stainless mugs seem to be all the rage. So I bought one. Here’s the deal. The flavor has definitely been altered and not to the better. But it gets worse. I am on a 3 to 4 hour sleep cycle. Always have been. Not to worry. I like getting up at 3 am, fix a cup of coffee (using an Aero Press) and do some of my best writing for an hour or so. About 5:30 am I go back to bed and always get another 3 hours of sleep. Coffee has never been a problem. With the stainless mug I am buzzed so intently I cannot sleep. I hate that feeling. To get that buzz with the Aero Press I would have to have 3 cups. So it is back to my trusty ceramic mug. I love that thing. It is many years old, chipped here and there but fits my hand.BTW, you just can’t beat Aero Press IF you follow their directions exactly. Water at 165 degrees. NEVER let the grounds soak. Pour and push. You get the absolute essence of coffee, some say elixir. It has less acid and less caffeine. I promise you.

    1. This is rediculous of course … steel is not causing an increase in caffeine. As for the others posting that it affects taste: it isn’t the steel, it’s likely the plastic or silicone lid. If you put coffee in a steel mug and a ceramic, drink both from a straw with closed eyes, you won’t be able to tell the difference.

  10. I found this thread because I was searching for an answer as well. The stainless steel does affect the tast somehow. I’m a fisherman, there’s a neat little gadget sold to help get odors off your hands, such as fish. It’s a stainless steel bar of soap(not made of soap but shaped like one) . Just rinse your hands in water with the bar and it neutralizes odors. If you google it you’ll see what I mean.

  11. Metals are reactive with acidic and alkaline foods. If you’re cooking with ingredients like tomatoes or lemon juice, your food can take on a metallic flavor when prepared in a SS vessel. This is common knowledge. It’s the same deal with coffee.

  12. Of course it affects the flavor. Metals are reactive with acidic and alkaline foods. If you’re cooking with ingredients like tomatoes or lemon juice, your food will take on a metallic flavor when prepared in a SS vessel. This is common knowledge. It’s the same deal with coffee.

  13. Same experience, when using stainless steel mugs with coffee and creamer there is a sharper acidic taste and I cant leave coffee out as long as I can with ceramic cups.

  14. The article is not true. From my experience. Not only does stainless steel change the flavour, but it also makes my throat hurt. This includes stainless steel thermos brands and hot water dispensed from stainless steel tanks (Gas stations or home espresso machines)

    Glass is the only material that does not give me a sore throat and all previous flavours can be washed off with soap.

    1. Yess! My throat hurts too! Tastes SO much more acidic even though it’s made in the same machine and I only change the cup to SS. Disappointed I need to stick to cold drinks with my Yeti. It does keep coffee so hot, but I HATE the taste.

  15. We have a metal coffee carafe for our coffee maker. We opted for it instead of the glass version with the hot plate underneath. I find that all coffee tastes more acidic and I don’t enjoy drinking it… at all. I can’t find the science to support this claim, but I know it’s true. I would love to see a blind taste test!

  16. I completely agree that stainless steel mugs makes coffee taste off. I only use disposable paper coffee cups now for travel.

  17. The steel itself has flavor, smell it then tell me otherwise. Explain why it doesn’t effect the coffee flavor? Personally I can’t stand a stainless steel coffee mug or thermal bottle.

  18. It’s the same here in England. I decided to switch from my aluminium moka espresso pot to a similar one in stainless steel, made by Bialetti no less, so not cheap. I also bought good quality coffee beans from a boutique store in London’s Soho.
    Imagine my horror at the metallic aftertaste, even after a dozen attempts…I thought it was the high roast beans, but no it’s the pot. Coffee tastes better medium ground in my cafetière which of course is glass. I don’t know whether to persevere or just throw it out…

  19. seems like most of you suffer from a placebo affect with this. i drink both tea and coffee out of both steel and ceramic mugs. i do not notice the difference.

  20. The article is correct. It doesn’t change the taste (consider that most of the wine in the world is in steel before glass).

    It’s not the steel you’re tasting, it’s the way your mouth is reacting with the metal. People that drinking technique is a little sloppier are more likely to claim this to be a problem. Less polished metal will react more quickly with your tongue and lips, so the drinking vessels with the brushed interior are more likely to produce this (they also won’t impart flavors b/c less porous. Buy a mug with a mirrored or electropolished interior.

    Travel tumblers and lidded cups are a horrible way to taste your coffee anyway because the coffee can’t breathe and you can’t smell it. There is stainless steel mugs with a classic shape, no lid and a mirrored interior and the coffee tastes great out of them. They’re the first mugs grabbed from the cabinet in a house full of coffee snobs.

    1. So, if I just stop licking the inside of my coffee cup, and drink it through a straw, it won’t taste bad? Not buying into that.

      And as to “placebo effect,” I suppose there is some sort of folié a groupe going on, where everyone on this thread only thought about stainless making coffee taste bad after reading others’ questions.

      Or, perhaps, there are different grades of stainless steel, some more reactive than others?

  21. I got stainless mugs to use with my coffee warmer. I had no expectation whatsoever of a different taste and it was very noticeable the first time, second, fifth. It’s the same strange taste every time despite my high motivation to enjoy coffee that doesn’t get cold. I had some green tea in it and it seemed fine. I don’t drink that as much so I wouldn’t notice a difference as easily though

    At least I can use the mugs for tea, I think I’ll leave it to someone else to ever taste test coffee in a stainless mug again

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