"I'm still skeptical of the cleanliness of the tube that runs the water back to the filter basket."

That most likely is the source of the problem. Yeasts, fungi, bacteria, viruses can all harbor there. It doesn't get much air inside and never dries out, leaving a medium on which these things can grow. If you saw slime in the water reservoir think of what was growing in the tube. The tubes on beverage makers, soda guns, juice machines, ect., is one of the big things on the list, that the health inspectors check at restaurants.

What do you use to clean them? Run vinegar through them?

I perk a pot of straight vinegar every once in awhile ( probably not as often as I should) There used to be a product called *Dip It* to clean coffee makers but I haven't seen that in a long time. Must have been discontinued. Anyway, the vinegar works good and then you can pour it down your drains with some baking soda as a drain cleaner.

I bought some dip it cleaner just the other day at my grocery store (Winn Dixie).

I actually run the same pot of straight vinegar through several times. EAch time it seems to come out darker, leading me to believe it needs more than 1 trip through to work.

Here's an idea: do you fill the coffeepot reservoir the night before, to have it turn on with a timer? Sitting overnight might not be a good idea. That occurred to me, because I saw my water filter pitcher was scummy in the bottom one day, and I extrapolated to the coffeemaker. Since then I fill the reservoir in the morning and then run it immediately. Leave no water sitting around incubating stuff.

I've never been a fan of letting coffee or water sit overnight. It certainly doesn't produce better-tasting coffee, and I personally don't find making a fresh pot in the morning that time-consuming. I always let the pot and basket dry before putting them back on the coffeemaker and believe the coffeemaker itself (well, at least parts of it) gets a good drying simultaneously.

I do leave water and rolled or steel-cut oats overnight (or rice and water all day) in our high-tech rice machine. It has no tubes or hoses to harbor water, bacteria, mold, or other nasty stuff, and gives the mix a thorough boiling as part of its cooking process.

I'm glad to hear someone else runs the same straight vinegar through several times. I'm not sure about re-using it in the laundry, however, as it may have picked up some substances that could stain clothes, towels, or linens. Does everyone remove their coffee maker's water filter before vinegaring the machine? I forgot that once and think it had a negative impact on the filter.

I could not get refills for that filter so took it out shortly after we bought the coffeemaker. We filter the water separately anyway in a Pur or Brita pitcher. The filters are usually charcoal, I would think it would soak up the vinegar like a sponge.

After running the vinegar through several times I either pour in my sink to soak, or in the toilet.

I specifically started an account here to follow up on this post.
In October 2007, I started working for a small home-town Insurance agency. After a few months of working, I noticed that whenever the coffeemaker started brewing and the smell was wafting through the office, it would make me nauseous almost dizzy. When I got a cup of coffee I didn't want to drink it even though I wanted (and sometimes needed) a cup of coffee. At home I have no problems with my coffeemaker, enjoy inhaling the aroma, and never have any ill reaction to it. We also purchase the same coffee.
I stopped working almost a year after I started, have had time off for about a year and recently the office asked me to come in to cover for a few hours.
TODAY, my boss started a pot of coffee. SAME REACTION!
I notice the coffee pot is ancient and has probobly NEVER been cleaned thoroughly, I ran some water through it a few times and cleaned what I could before.
Maybe we are on to something here! Maybe hundreds of thousands of people are slowly poisoning themselves with their old coffeemakers!
I am going to mention this to my boss and suggest to him a new coffee pot! Maybe that is why he has MANY health problems!
Thanks for the post!

OT - I'm sure. When I got my first USAF assignment after basic the Sargent told me to come in early and have coffee made when everyone else arrived. I came in early, cleaned the coffeepot, made coffee and got a thorough chewing-out. I was told it was common knowledge that coffee pots were never to be cleaned, only rinsed. This would have been about a 60 cup aluminum coffeepot. I seem to recall that my grandmother had a small aluminum coffeepot which she never cleaned, only rinsed.

Tomatozilla -
There are a few bacteria and molds that could get a foothold in some of the tubing and build up a colony. However, they are not the ones that cause classic food poisoning or food-borne infections.

The amount of those microorganisms it would take to give you an immediate "indelicate condition" is so big you would be seeing chunks in your coffee.

My guess - you had something else.

I too have been experiencing early morning 'intestinal issues' for a long time. Last week, I was on vacation and never once had a problem, even though I was drinking the same amount of coffee as soon as I got up every morning. The first morning after coming home, my problems returned.

I use a single-cup Senseo coffee maker (and LOVE it). I was already wondering if there is something different about my coffee that could be the cause of my problem. I am running pure vinegar through it as I write this. This coffee maker has a water container that holds enough water for me to make a large mug of coffee for 3 days before it needs to be refilled. I guess I will start dumping it after each day's brewing session and filling it with fresh water each morning. It will be interesting to see if my problem goes away.

"This would have been about a 60 cup aluminum coffeepot."

Aluminum is very reactive. What did you use to clean it with?

I'm cleaning my coffe maker w/straight vinegar as I write this! I use white vinegar w/bking soda all the time to clean my drains so today I will put vinegar thru several times. Thank you all for the re-use vinegar tip.

As an update, I posted last Wednesday that I was cleaning out my Senseo coffee maker with vinegar to see if I could eliminate my early morning intestinal issues. Since cleaning my unit, I have been dumping the water out of the tank after every mug of coffee I make - AND I've been using filtered water from my refrigerator instead of tap water. I haven't had any 'issues' since.

My dad has had the same coffee pot since I was in high school, and has never once ran vinegar through it, let alone cleaned it in any way. He, like many of us, was under the impression that the coffee would be hot enough to kill any germs etc. Over the past few weeks he has noticed that every time he drinks coffee at home, his stomach gets upset (not drastically, but noticeably). When he drinks it at work each day, he's perfectly fine. It is true that dispensers in restaurants are thoroughly checked by inspectors for good reason; perhaps we should all think twice about the tubes and water reservoir; of COURSE these are moist, warm areas perfect for ickies to live in. I am going to run the vinegar through immediately, and I just wanted to thank those who gave advice instead of rudely dismissing the issue.

Thanks to all for these posts. I realize this is happening to me at work and plan on cleaning our maker and its carafe soon. I have experienced classic food poisoning in the past, which is bacterial. But algeas, and it seems people are saying that they are growing algeas in their makers, can secrete toxins right into the environment. A reaction to a poison would not require time to develop, particularly if you're sensitive from repeated exposure. I would suggest regarding an old fashioned aluminum pot that having rinsed it, scrubbing it hard with a tablespoon or so of salt, then rinsing again, will get rid of any sliminess without leaving any residual flavors. Works good on a dog's water bowl too.

OK......>Running straight vinegar through mine as I write this too! I've always turned my coffee maker upside down to drain any water that might be in it onto the counter, then rinse the pot and the basket and I leave the lid cracked so it can dry out between uses. But how in the world are you supposed to get to the inside of those tubes? I've ALWAYS wondered what is growing inside of those tubes but could never get to them.

I just drank 2 cups of coffee from my local diner. And I'm home now staring at my Mr. Coffee coffee maker. I can find Dip-It locally and use it maybe once a year. I seem pretty unaffected by my consumption of coffee. My immune system seems to have adjusted to fight off anything in coffee makers. My Grandma told me you have to eat a peck of dirt before you die.

Lately I've been wondering why white coffe makers are becoming scarce.
Now I know....Inside my water reservoir and in the corners has lots of crud, I have been cleaning it our every so often, however dirt keeps coming back.
It's my opinion the black coffee makers hide the junk that's laying in the areas hard to clean.
I am looking for a SS electric pot that's reputable .
So far I haven't found any, these electric coffee pots can be cleaned and no hidden areas exist.

I know this thread is a bit dated so I hope people will still receive my post, but YES Tomatozilla - I have just figured out I've been experiencing the same issue with my automatic coffeemaker! I had not used it for a year until today, and last I used it and packed it away a year ago (and I was getting extremely nauseous and stomach upset, hot/cold symptoms every time I drank the coffee,) I noted how dirty it was and cleaned it just with hot water and dishsoap. Well apparently thats not going to do it, because I just brewed a pot this morning, and now, I have been sick all afternoon with nausea and stomach cramps. So I decided to do a search and here I came across this thread. Thank goodness I am validated on this and now I know what to try. I am thinking not only will I clean all components by hand in hot water with straight vinegar, but might also run straight vinegar through 3x, and with baking soda the third time, and straight water a final time to rinse out the baking soda. My rationale is the first three rounds should loosen the crud and kill most bacteria, the fourth with baking soda would fizz and get into every crack and cranny possible, and finally the water to rinse it all out. Not sure if the baking soda will be good for the machine, but if not I am not too concerned, as the machine is not expensive... Please update me on your experiences, whether the vinegar/etc has continued to work for you, and thanks to everyone who posted valuable information on this.

Also, I wonder if a french press or something like that might be more healthy and hygienic. I am going to have to remember to ask my physician next time I see her, she is good with suggestions and will let you know what I come up with.

I soak my teapots in water with a little Clorox bleach. I wonder if you should soak the tubing in chlorine bleach water too.

I don't think any of you have ever seen the inside of a water line that runs to your sinks. We had rental and I watched my husband work on the faucets and lines to the sink. Yuck, they are full of that slime buildup. He lived there for awhile and was never sick and I am sure it is in our new home's plumbing by now.

Regarding a coffee pot, I doubt there is anything harmful in the pot unless it is something that you are allergic to. The coffee gets hot enough to kill anything harmful if it was there.

I run straight white vinegar through several times too. Then run straight water through a few times. It still tastes a little like vinegar for a couple of pots but not bad. It makes a world of difference in the taste of the coffee. It's just a lot better tasting after that faint vinegar taste is gone, maybe it is just my imagination. Then I pour the vinegar down my garbage disposal along with all the pots of water brewed because sometimes that thing gets a smell too. I don't use it very often and I think that is not good for it. So I get two cleaning jobs out at once with the same vinegar. I have a skinny brush that you can clean the water viewer with but never thought of cleaning the other tube. Will have to try that.

I know this is crazy to think about but I bought a used coffee maker from e-bay because Krups no longer makes a certain model and it's the best coffee maker ever...!!! so I thought what the heck I'll try it. I cleaned it like there was no tomorrow. It seems fine. It was clean when it got here but I still monster cleaned it. There is still one left on e-bay I'm tempted to get it too but maybe I wouldn't be so lucky next time!

I sometimes get a case of stomach woes from the coffee and have to dash to the ladies room. I often wondered if it is something to do with the pot. Or maybe that it is a hot drink. Couldn't believe OP posted this as I have wondered the same thing!

We are HUGE percolator fans. I have a Presto right now that I love. Here is why:

1) Coffee is always *really* hot.
2) All stainless interior.
3) We use four smallish scoops of coffee for 12 cups. Big savings.
4) Run Dipit through every couple of months and it's clean.
5) Taste. Best tasting coffee anywhere.

You can buy them on Amazon and they use the 3.5" disc filters. Farberware also makes them and we used to have one. Downside is after three or four years of daily use the heating elements in the Farberwares seemed to fade. I'm hearing better things about the Presto's lifespan but have only had it a short time so far.

Here's the thing, I only get the tummy upset in the mornings and not all the time. If I make a pot later in the day it doesn't upset my stomach at all ever. Weird...

Various descriptions above read like Irritable bowel syndrome to me.

I was recently diagnosed with ulcerative colitis and when I first started having symptoms was only when I drank coffee. The 2 may not go together at all, but I've always wondered if a dirty coffee pot could make me sick. Basically ulcerative colitis is inflammation of large intestines. There are studies that suggest that the inflammation is caused by some unknown pathogen. Who knows if I was ingesting bacteria over and over again.there were other factors like stress that triggered mine, so I'm not saying it was a coffee pot. It just causes me to be cautious. A great alternative is to buy a French press ( not expensive) and have French press coffee. It has no tubes at all and no hard to reach compartments. It's also the tastiest way to have coffee

I think I read this original posting & have been cleaning my coffee maker w/white vinegar ever since. Actually I leave the vinegar in the machine for about an hour before turning on so it has a chance to do what it does. I too then pour down drain & add baking soda. I love the idea of using the vinegar more than once. Good suggestion!

I too signed up to leave a post as I was researching
the cleanliness of Mr. Coffee and similar coffee makers. My conclusion: they’re
breeding grounds for bacteria. If you look in the bottom of the coffee maker you
may see red or pink around the hole or in the tiny spaces you can reach to
clean by hand. This is a bacteria
known as Serratia marcescens. I took my Mr. Coffee apart and poked white
pipe cleaners of various widths into the holes in the reservoir and through the
plastic tube-- all came out bright red. And of course you can’t even get
into the lower reservoir. Who knows what that looks like! I’m going for a
percolator. Yes they still make them but could only purchase them online.

I use instant coffee, it's easier on your stomach if you have indigestion problems.

Actually bacteria do not like coffee grounds(they are mildly acidic), they do like warm and moist conditions though. You should wash your carafe and filter housing after using, once a month clean with white vinegar. As with your washing machines(clothes and dish), you should let your coffeemaker air out after using to keep mold and bacteria from growing.

If you are wondering what to do with your used coffee grounds, you could throw it in your compost pile. Worms love used coffee grounds.

Icky Stuff Lurking in Your Coffemaker

Composting Used Coffee Grounds

You're absolutely right: bacteria loves warm, moist conditions. The bacteria I'm witnessing isn't growing where coffee grounds or coffee is. It's growing in places not easily reached by either hand washing or running vinegar through. Look at your coffee maker, take it apart to get to the plastic tube and you will understand. Also the lower "tank" can never be cleaned or aired out. Water still dribbles comes out after days of airing and turning the maker upside down multiple times. My maker was regularly cleaned with vinegar. I even used hydrogen peroxide. But you can't clean what you can't get to.

Wow. This all makes me very glad I only make coffee by the pour over method with a Melitta filter holder. Both filter holder and kettle can go into the dishwasher for sanitizing when I've made my cup. Very convenient too if you only make 1 cup a day like I do.

I recently purchased a Hamilton Beach coffee maker that makes either single shots or a full pot. From day one I tasted a metalic/plastic taste which I've been trying to remedy (unsuccessfully). And whenever I drink the foul tasting coffee, I get bowel issues. I even vomited the first time. Thinking it was a virus, I originally didn't relate the two things. Rather than food poisoning from bacteria or such, I'm thinking this might be more like chemical poisoning. It doesn't happen when I drink coffee from any other source, only with coffee from the new (repeatedly cleaned) maker. Anyone know what chemicals they might be using in the new maker?? (And if it will go away?)

I never buy a coffee maker before inspecting how can I clean it. My present maker is a 4 cup Mr Coffee, it can be cleaned thoroughly with baking soda and a long thin bladed knife with pieces of towel to get into the corners. I also run baking soda / vinegar at different intervals through it, and rinse also. The carafe cleans up like new with baking soda.. I like a clean pot, makes the coffee taste better. Yes I sometimes need to make another pot, however others are just not able to be cleaned

Yes. I found a coffee maker in storage at work, cleaned it up, and made pot. After drinking the coffee I got a burning pain in my stomach. The next day I cleaned it more with two cycles of white vinegar and about a dozen cycles of water. I made another pot and the same thing happened; only this time it turned into cramps that lasted for three days. That was 5 days ago and my stomach is still sore. I went to the doctor and found I have internal bleeding. At times I feel really bad; like I'm taking the flu. I took the coffee maker apart and the heating coil is aluminum. Warning! Don't use an old filter type coffee maker that hasn't been used in a while. They are poison!

OH MY GOSH! So is that for 100 percent sure what caused the internal bleeding? That's pretty scary. When you say "don't use old type filter machines" - can you be more specific? It sounds as if you're saying any drip coffee maker that uses a paper filter that you put coffee grounds in.

My coffee maker is a kitchenaid drip coffee maker and I cleaned it the other day. It gets used frequently. It has a removable water pitcher from the back and it actually felt a little slimy on the bottom, and only filtered water goes in there, nothing else - and it even has a vent hole so that it can get air in the pitcher that holds the water - and I always turn the maker upside down to let all residual water come out into the counter then wipe it up so it can dry as quickly as possible... examining the coffee maker it seems pretty clean. the hoses look like a plastic material to me, not aluminum.

I'm so sorry you're having to go through this - it sounds awful.

Most (filtered) coffee makers that I've seen are very obstructive internally..Before I buy one I look into the water chamber, if I can't see everything I won't buy it. I use a $15,00 black & Decker 4 cup pot that's wide open, when it get soiled I fill it with a solution of baking soda, let it sit a while and with a sharp object and strong paper towel go deep into the corners to get the crud...Even though I use nothing but filtered water there's always a crud build up...I'd hate to see what these pots are that cannot be viewed into the crevices.

I've had a lot of drip coffee makers - and I'm like you, Japus, I want to be able to clean it as best I can...You should try one where the water chamber is totally separate from the unit itself, like my Kitchenaid. After having this I won't buy one unless the water chamber is separate. Coffee scum isn't able to get in there. The only thing that goes in there is filtered fridge water. I'm able to take it off and wash it top to bottom. Also, the way this is designed, during brewing, you don't get any coffee splatter during brewing on the machine except for the area where the dripping occurs - the way it's designed, the rest of the coffee maker is sort of sealed. The only thing I cannot get to is the line that runs internally, so I'm hoping vinegar and hot water and frequent use are keeping bacteria low in that line....I might try baking soda

A family member works for Whirlpool in Greenville, Ohio - a few years ago, she gave me 2 Kitchenaid coffee makers. I still have one unopened. I've been using this one at least 3 years, maybe 4. I went to amazon and noticed this one is almost identical to mine, other than the front digital part which looks like it has minor differences, but otherwise, it's the same.........Another thing I will add, I have a Mr. Coffee 8 cup thermal carafe that fits it perfectly, so I use that instead of the glass one that came with it......

Here's the one I have - or at least very close to the one I have - I really do like the design. I think it's the best coffee maker I've ever used. easy to clean for the most part and very reliable.

Kitchenaid Coffee Maker

That's an old post I know but I thought to share my feedback. I got exactly this same sickness and stomach upset feeling with a specific coffee machine, and guess what? It's a brand new coffee machine. I have another machine, and use a French press every now and then but I've never got this feeling when using them. I'll try cleaning this new one with vinegar, otherwise will obviously return it back.

Has anyone switched from a regular coffee maker or Keurig to a coffee press or pour over method??

This is interesting! I had not thought about this but anything that stays damp will get moldy so it makes perfect sense to me! The part of the drip maker that holds the water, stays moist all the time. I bet there is slime in mine too! YUCK! Anyone that says that drinking slime wouldn't cause you to be sick isn't using their heads!

We just got a new coffee combo machine and a friend wanted our old one. I thought I should give it a cleaning and new filter. Omg! Omg! I may NEVER EVER drink coffee anywhere but home again! The water reservoir was the most sickening sludge filled thing! I had NO idea or took a split second to think about this nasty build up! Seriously... I used a baby bottle brush and nearly an entire roll of paper towels cleaning it up. I had always cleaned my pot and sterilized the outside! ‍♀️ I’m wondering if a teaspoon of bleach on occasion would be okay along with a could runs of vinegar? ☕️

I don't know whether bleach would be ok for your machine, but do not mix chlorine bleach with any other cleaning product! Many of them, like vinegar, will cause a chemical reaction which releases highly toxic chlorine gas. It can damage your lungs among other things.

Thanks! Yes, I know about combining products. I’m going to run a teaspoon of bleach with a full pot of water once a month. I will post the results in a few months. To me, I had rather purchased new coffee maker once a year than ever find that I’ve been drinking pond scum. I’m still a little freaked out!

Thanks for the reply! Happy New Year!

Stovetop espresso makers aka moka pots are also a good alternative- the pressure brews a stronger cup than a drip usually does, but not nearly as strong as actual espresso and when done right it's extremely delicious and it's much easier to clean and keep clean

I leave a small piece of copper wire in our Brita pitcher and never have slime build-up, even though we leave it on the counter, not the refrigerator. After reading this thread, I'm thinking of doing the same with our Technivorm coffee maker reservoir.