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Which Coffee Makers Don’t Get Moldy?

The French Press, Chemex and Percolator are examples of coffee makers that are resistance to mold and other germs due to their open and simple designs.  Mold generally wont grow because these methods don’t have enclosed areas to trap moisture  and feature simple parts to clean!

Which coffee makers don’t get moldy?  Any coffee maker without enclosed parts to trap moisture and coffee residue will not have mold problems.  According to a NSF study of germiest home items, coffee reservoirs are one of the dirtiest places with yeast, mold and E. Coli.  The Chemex brewer, French press and Percolator don’t have spaces to trap moisture and generally are considered much more flavorful coffee then the standard auto drip coffee makers.

 The Chemex brewer is the easiest to clean and has the least areas to trap moisture and particles.  Essentially an open hourglass, water will evaporate out without being trapped. Being clear glass mold cant hide in any dark places either.  

 The French press is a second choice due to having some areas that can trap moisture and residue namely in the screen and various small parts. Very easy to clean as disassembly is simple as unscrewing the screen and giving it a quick cleaning.  

Finally the stovetop Percolator comes in last. While these brewers are generally all stainless steel and get boiled on the stove to a full 212 F, they can trap a lot of moisture and residue.  Leaving a Percolator with grounds and full of moisture is still not a big deal. Often I forget to clean out my Percolator and remember the next day or two later. Simply disassemble the pot give it a quick clean and you are back to brewing.  Not one Autodrip will be this simple to clean or stay as clean.

Read on to find out what makes each of these coffee makers so awesome, beyond being mold free!  You might even find your new favorite way to brew coffee.


The Chemex is my latest brewing technology and one of my favorites.  I don’t recall where I first saw this but I have found it makes the generally the best coffee.  For those that somehow have not discovered the Chemex yet, it is really just a conical filter in a fancy glass carafe.  But the magic is in the filters because as the story goes a chemist came up with the idea for Chemex with his knowledge of chemical extractions and processing.  One thing I didn’t realize was how old this invention is though as it was invented in 1941! So much for being cutting edge I guess.

I really like it because it filters exceptionally well yet leaves the coffee smoother than autodrip.  I find the best autodrips with good filters, still somehow make the coffee harsher. This may be the fact that autodrips have a lot of nooks and crannies that trap old coffee residue and particles.   Maybe it’s the mold or E Coli!

 I also have read in several resources that autodrips generally brew too cold versus Chemex where you are more directly controlling the water temperature from your boil kettle. I would agree as often by the time my pot of autodrip is done it’s usually warm but not piping hot.  According to the Speciality Coffee Association of America the golden temperature for perfect brewing is between 195-205 degrees Fahrenheit. This is definitely not a problem with the Chemex as you pour almost boiling water directly over it and get the ideal temperature. One final note on the Chemex it certainly is one of the most elegant pieces of coffee hardware you will have in your kitchen.  I often do marvel at both the simple yet elegant design. I see why this design has been placed in several design museums as a work of art.


Ah the percolator, another very steampunk looking gadget that makes awesome coffee on the stove or in the camp fire.  My small five cup percolator has survived many campfires and charcoal grill brews. I only melted the plastic top once because I put it on too small a grill and put a hot lid directly on top of it, whoops.  I wouldn’t mind a nice glass perc top though as I’m not sure if I like plastic getting soaked in boiling water.

The percolator is also an old style coffee maker predating the autodrip by about 150 years. Invented as alternative to tea and beer it allowed easy brewing of coffee for its stimulating effects.  It works by using gravity and the action of boiling to pump water on top of the coffee similar to an autodrip. The main drawback is it recirculates already brewed coffee over the grounds. In all my years of brewing with a percolator I have never found myself with a single bad cup other then putting too few grounds in.  

Is it the best coffee maker? I think it’s certainly one of the more robust ways to brew coffee. You feel like your drinking a manly cup of motor oil for sure. I do find it to have a lively and robust flavor. Though in my last post my back to back taste test results were surprising! I have only one complain generally that the grounds do get into the coffee and that is irritating to my throat.  If you have acid reflux a percolator pot may not be your best coffee maker.

French Press

If the chemex and the percolator had a baby it would be the french press.  Is this the best coffee maker for you? Well maybe, purist argue it gives you the best and truest flavor.  Haters say it gives you a over extracted cup with a fine soot of grounds in every cup. Would I agree with both points, well yes.  I do love my french press though again I do find the grounds/soot irritating. Before you say it, yes I do try to pour it off into a serving carafe after it brews but you still get some level of residue in the coffee.  Maybe I need a new one with a better screen but it works for the occasions I use it. Also very aesthetic this is also one of the more pleasing coffee makers to have around, especially in stainless steel.

Related Questions:

Should you clean your coffee makers with bleach or vinegar?

If you decide to go with either a french press, percolator or Chemex pot good news you don’t have to use bleach or vinegar to clean them as they dont trap residue and moisture.  Bleach and vinegar cleaning is focused on autodrip coffee makers to fight the germs that develop in the enclosed areas. While both will kill germs in your Chemex, french press and percolator it is unneeded.  SImply rinsing out these coffee makers after a brew will eliminate this issue. NOte it may be effective to occasionally use vinegar to give one of these a more through method. I find sopa can leave residues even in stainless steel and contribute off flavors.  VInegar has not ever been an issue in anything I cleaned.

How often to clean a coffee maker?

Using the Chemex, french press or percolators eliminate the need for frequent cleaning with a simple rinse.  SInce there are no enclosed areas cleaning is not generally required. The french press screen may need an infrequent bruising with a soft bristled brush to remove embedded coffee grounds.  The percolator also may need to be disassembled infrequently to clean all the enclosed areas like the perc top threads.

Should you use no rinse sanitizers from beer brewing?

The point to understand with no rinse sanitizers from beer or wine making is that they are made to kill germs but not clean.  What this means is that while sanitizers will kill germs or mold but they will do nothing for coffee residue. Considering this I would not recommend using this in coffee equipment solely because it won’t really help anything.