We noticed one day, while refilling the reservoir on our Keurig K50 classic coffee maker, that it had a greenish tint inside of the reservoir. Greenish tint?!
Having a swimming pool, the greenish tint was instantly recognizable. Algae!
After browsing through some information online about mold and bacteria inside coffee makers, we learned that all coffee makers, including regular filter and pot makers, do get mold and bacteria build up.
Not only mold and bacteria, but algae too!
So, we decided to figure out the best way to clean and sanitize our Keurig coffee brewer –
and we do mean… get it really, really clean.
We will be talking about several things in this article.
- Why you need to deep clean your Keurig coffee maker.
- Removing algae, mold and bacteria form your brewer
- Cleaning the internal parts of the brewer
- Cleaning the external parts of the brewer
- Descaling your Keurig brewer.
- Deodorizing your Keurig brewer.
- Regular maintenance of your coffee maker.
And along the way, we will giving you many tips of how to deep clean your Keurig coffee maker and how to keep it clean – and what not to do.
So, what can you do to disinfect and sanitize your Keurig brewer and get it really, really clean?
Are there toxic mold and bacteria in your brewer?
No matter how desperate you were for a cup of coffee, we don’t think you would brew your coffee with water out of a pond.
Is it possible for toxic levels of bacteria and mold to build up inside your Keurig coffee maker like the water out of a pond? Not really. More than likely, there will only be trace amounts of either algae, bacteria or mold.
But, we want the cleanest water and environment for brewing our coffee because… not only is it healthier, but our coffee will taste better.
Chances are good that your coffee maker (Keurig or not) has some bacteria, algae and mold developing inside of the machine. It can manifest inside of any part of the brewer – the water reservoir, the tubing, the heater, the pod holder, or any part.
Heating the water helps to sanitize.
That being said, we should point out that most single serve coffee makers, including Keurig, heat the water to about 190 degrees F..
Most common bacteria die off at about 104 degrees F.
Most common molds die off at about 140 degrees F.
It is less certain what it takes to kill off algae, (algae have been discovered in the ice of the Arctic to volcanic heat vents under the ocean) but to kill most common algae anything over 110 degrees F should do the trick.
So, once the water from the reservoir reaches the water heater and is heated inside the coffee maker, it does kill almost all of the bacteria, algae and mold.
If that is the case, do we really need to clean our Keurig brewers at all? Can there still be problems with these unwanted intruders?
Yes, because they can build up in the parts of the brewer before the heater.
And if the machine sits with no power between uses, then those intruders can build up inside the heater during that time span.
Let’s look at each of these organisms one at a time.
Bacteria inside your coffee maker
There are many types of bacteria, and the more harmful bacteria strains are not as common as other not-so-harmful or completely harmless strains. Harmful, toxic bacteria could still be in your brewer in small trace amounts.
It’s not just the toxic effects you need to be worried about. Bacteria, even harmless bacteria, can have byproducts that cause other undesirable things in your coffee maker – like odor and bad taste.
Now, if you have city water, it is filled with chlorine for the soul purpose of killing off bacteria and any other organisms. In fact, there is as much chlorine in the water from your faucet as can be found in a public swimming pool. Yes, it’s true. You can test it yourself.
Some of the chlorine is taken out through water softeners and water filters. Charcoal filters are especially good at removing chlorine.
The Keurig water filter, inside of your Keurig water reservoir, is a… charcoal filter, and does reduce chlorine levels. Reducing chlorine levels, however, may allow bacteria and mold to grow inside your machine.
You can find bacteria living inside your brewer in any part. Again, probably not in toxic levels, but better to be clean (safe) than sorry.
Algae inside your coffee maker water reservoir
If you haven’t cleaned your Keurig water reservoir in awhile, take your finger and feel along the inside of the reservoir near the bottom. Does it feel slimy? Slippery? If it does, then you have some mold or more likely, algae buildup.
You may even see, if you look closely and hold it up to the daylight (as we did), a slight greenish tint. That is for sure some type of algae buildup.
Algae lives in or near water and requires sunlight or light to live and grow. In fact, keeping your Keurig coffee maker with the reservoir exposed to sunlight will increase the chances of algae buildup in the reservoir, and throughout the rest of the brewer.
Is this algae buildup going to be bad for you or toxic? Probably not. There are many types of algae and they are generally not very toxic.
But, bacteria, which can be toxic, love to flourish in and around algae.
Algae will most likely abound in your water reservoir where the water is exposed to sunlight or other light sources. Then it can get sucked into the brewer from there.
And besides any toxic effects, algae may affect the taste and smell of our coffee – giving it that pond water aroma.
Mold inside your coffee brewer
Some molds can be very toxic. You won’t find mold living in water, like algae, but they do like a moist environment – which abound around your coffee maker.
Mold does not always require sunlight to grow and abound. So, mold can build up in the darkness inside the brewer.
You may find mold inside your reservoir, inside the machine internal parts, inside the heater tank, and in the outgoing external parts of the brewer like the pod holder.
Dealing with scale inside your coffee brewer
The other thing that builds up in your brewer is scale.
Scale is minerals the leech from your water and cling to parts of your coffee maker, inside and outside.
Scale is not toxic and does not need disinfected – but it does need dealt with.
Descaling your coffee maker is another topic entirely – which we have covered in detail in the post linked to below.
Again, scale is not toxic and any buildup should not change the taste of your coffee. But, the buildup does have a tendency to plug up the lines in your machine. This will cause the early demise of your Keurig brewer, which is why Keurig recommends frequent descaling.
Why take the chance on any of that – and we want our brewers really really clean, right?
When you do descale your coffee maker, you are also working toward sanitizing and disinfecting it.
A first step in cleaning and sanitizing is to descale your brewer – do this first.
Cleaning out the algae mold and bacteria from your single serve coffee maker with white vinegar
In this section we will deal with disinfecting and sanitizing your coffee brewer of algae, mold and bacteria – both inside and outside your Keurig machine.
You have just descaled your brewer. What else do you need to do to get rid of the toxic elements inside the machine?
Whether you have used the Keurig brand recommended descaling solution or you have used distilled white vinegar, there is really nothing more you need to do for the inside of the coffee maker.
That’s right, nothing. Because in the case of distilled white vinegar, it has properties that are anti bacterial along with anti algae, and anti mold.
The same acids that worked at descaling also kill mold, algae and bacteria.
Does white vinegar kill everything? No, it does not kill all bacteria. Some of the more resilient bacteria like streptococcus can remain. But, it does kill most bacteria and, is not caustic or harmful to you or your machine.
It is not recommended by Keurig, but the acidic content of vinegar is no more harmful than the citric acid that is in the Keurig brand descaler – as you learned in our descaling post.
To use it, follow the step by step instructions found in the post we just mentioned. That’s all you need to do to sanitize and disinfect the inside of your brewer, The outside we will cover in a minute.
Is there anything more you can do to sanitize your coffee maker?
Using hydrogen peroxide to clean your Keurig coffee maker.
Yes, you can go one step further.
Another anti-bacterial you can use is hydrogen peroxide. It is very effective at killing unwanted organisms, mold, algae and bacteria- and is not toxic or caustic when very diluted.
It is an oxidizer, though. That means it can oxidize or corrode the metal parts of your brewer. So, don’t leave it sit too long in the machine and make sure you rinse out the machine thoroughly.
Hydrogen peroxide has a couple of advantages over white vinegar…
First, it has no odor and using it generally acts as a deodorizer.
Second, it has a taste very close to water itself. This means it will not leave behind residues that will affect taste.
In fact, hydrogen peroxide generally neutralizes both odor and taste by oxidizing and destroying components that may cause bad odor and taste, like bacteria, for example.
How do you use hydrogen peroxide to clean your Keurig coffee maker?
Simply repeat the steps used in descaling your Keurig brewer with distilled white vinegar. We will give you those steps again replacing the vinegar with hydrogen peroxide.
Step by step using hydrogen peroxide
These is the step by step method for models with a larger removable water reservoir.
- Empty the water reservoir on your Keurig.
- Remove any filter and filter unit from your reservoir if you have one installed.
- Use a large coffee cup or container for hot liquids and pour about 5 oz of hydrogen peroxide 5% and pour it into your reservoir. Do this twice (10 oz of hydrogen peroxide total) for non pour-in type reservoirs – the removable type. ****Just use the cheap hydrogen peroxide found at your local drug store ***
- Fill that same large coffee cup with clean water you would normally use for brewing your coffee. And do this twice also for non pour-in reservoir type units.
- Place the reservoir back on the brewer, and make sure your Keurig brewer is powered on.
- Empty the K-cup pod holder – do NOT place a pod in the holder, leave it empty.
- Place an empty cup (10 oz or larger) and brew a 10 oz size cup. Do this until the brewer says to add water.
- Now let it set at least 20 minutes – that is all it needs. Don’t let it sit for more than 1 hour.
- After letting it sit with the hydrogen peroxide solution, empty the water reservoir and this time fill it with clean water. Run as many cups through the machine as necessary (without using a k cup pod) until needing to add water.
- You may want to repeat the last step to insure that you have removed all of the hydrogen peroxide solution from the brewer.
- You are now ready to brew coffee as you normally would.
How Keurig recommends cleaning their coffee makers.
If you visit the Keurig website and look for (or Google it) how to clean a Keurig coffee brewer, you will get a page on how to descale a Keurig Brewer.
Is descaling and cleaning the same thing according to Keurig? Well, sort of.
In the Keurig recommended cleaning process they suggest using a combination of descaling solution and water, about a 50/50 combination.
Keurig emphasizes the need to descale your Keurig brewer, but not so much the need to clean it or sanitize it, meaning kill the germs and mold.
Will using the descale solution also sanitize the machine? This is uncertain with the Keurig brand descaling solution, because it was hard to determine what ingredients are in the Keurig brand solution.
After some searching, we did come up with the basic ingredients.
What are the basic ingredients in the Keurig brand descaling solution?
Short answer: Citric acid, Silicic acid, Phosphates, Bleaching Agents, and Water. Get the details below.
Mostly, Citric Acid, about 50% or more. That means that more than half the solution is made up of citric acid. It’s a great descaling agent and is natural.
Silicic Acid, about 3%. Less than 3% of the solution is silicic acid. Silicic acid is “a weakly acidic colloidal hydrated form of silica made by acidifying solutions of alkali metal silicates.” This acts as a stabilizing agent.
Phosphates and Bleaching Agents, about 5%. Phosphates are a salt or ester of phosphoric acid. Phosphoric acids are used to enhance flavor in foods and are considered harmless. This and other bleaching agents are combined as the cleaning (not descaling) agents included in the descaling solution.
And the rest… water.
Keurig claims their solution will descale, remove calcium and other scale (mineral deposits) that may build up inside of the brewer internal parts and tank. (which we believe it does a good job) But is says nothing about cleaning any other elements like mold buildup.
Does the Keurig descaling solution also sanitize? Well, it may, because it does contain bleaching agents and phosphates- but Keurig makes no claims that it sanitizes or disinfects.
Keurig also makes no claims on their website that their descaling solution is all natural or non-toxic. Some of the bleaching agents may be toxic. And the phosphates are not very desirable either.
What does Keurig say about cleaning mold and germs from their coffee makers?. Well, nothing.
You can make up your own mind about how natural and chemical free you want Keurig cleaning experience to be. Or it may boil down to frequent cleaning and how cost effective you want your cleaning solution to be.
Either way, both ways of cleaning and descaling work well – it is up to you.
Cleaning the external parts of your Keurig.
You have cleaned the internal parts of your Keurig. Now what about the external parts, like the reservoir, the pod holder, and the drip tray?
Easy. Simply remove all the parts that you can.
Remove the reservoir and lid and then detach any water filter from inside it.
Remove the drip tray and separate any parts.
Remove the pod holder. It may not look like it will come out, but it does. Keurig has instructions on how to do this on their website.
All of the removed parts can go into your dishwasher. Most parts of most Keurig models allow for sticking them is a dishwasher.
If you don’t want to chance it, then simply wash them with dish soap and water as you would any dishes. Scrub them good.
And do not forget to rinse all external parts thoroughly, especially the water reservoir. Leaving behind soap residue will affect the taste of your coffee.
What you should NOT do to clean your Keurig.
DO NOT try using alcohol to clean your brewer internal parts!
Even diluted alcohol… and here is why.
It can be dangerous to put alcohol in a Keurig machine because of the alcohol vapors. As the Keurig heats the solution of water and alcohol it produces alcohol vapors – even when diluted. (We know this is true because we performed a little experiment in a pan on a stove.)
The alcohol vapor comes out of the solution along with the water vapor (steam), and it will catch fire. You can’t light the liquid solution on fire to save your life – but – those alcohol vapors catch easily.
It is possible that a spark or static spark or something else could cause vapors to ignite and cause a fire or explosion in your Keurig. We admit it is unlikely, but possible. (yes, we know there are Keurig-like alcohol beverage machines)
We do not recommend using ammonia to clean your Keurig.
It will be difficult to totally remove the ammonia odor and taste from your machine.
Don’t use household cleaners to clean your Keurig.
Household cleaner may do a great job at killing off bacteria, mold and algae – but they leave behind residues and chemical odors that you do not want inside your brewer and getting into your coffee. Oh, and then there are those potentially toxic residues left behind.
Can you use dish soap inside your Keurig brewer?
No way. The foaming agents will cause havoc and again the residues will be very difficult to get out of the machine.
Regular maintenance of your Keurig coffee brewer
Keurig recommends regular descaling using their brand descaling solution about every 3 to 6 months.
We think every 3 to 6 months is a good interval between each descaling of your brewer, whether you use the Keurig brand solution or white vinegar.
Considering that every descaling is also cleaning and sanitizing the internal parts, no more than 6 months is probably best even if you are using very clean water.
You may want to coordinate changing your water filter (if you have one) in your brewer with descaling your brewer.
The external parts and reservoir really should be cleaned at least every 3 months, or as often as you wish.
Don’t forget that there are 2 needles that puncture the K cup pods. Each can use regular checking and cleaning. Every 3 to 6 months is good for doing this.