Keurig K-Duo is one of the newer Keurig coffee machines available on the market nowadays but also one of the most popular with already around 20,000 positive reviews on Amazon.
However, proper maintenance of this machine is essential to keep the functionality the same as it did the day you bought it. It also helps you increase the longevity of the device!
Descaling is a vital part of a proper maintenance schedule and is often overlooked by most Keurig owners as an unnecessary hassle (when the machine appears to be working fine.. right?)
In this guide, we’ll explain why descaling your Keurig K-Duo regularly is so important, and how you can do it in a matter of minutes.
Not the right machine for you? Check out our other descaling guides for Keurig coffee machines below:
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Table of Contents
What is Descaling?
Water is the most dominant ingredient in a cup of coffee. But water isn’t just water. It contains minerals, such as magnesium and calcium. When you make coffee, these minerals get into the machine and form mineral buildup in and around the heating element of the coffee maker. These deposits are known as limescale (or ‘scale’ for short).
The process of eliminating the mineral deposits from the heating element is known as descaling!
How Often Do You Need to Descale Your Keurig K-Duo Machine?
The heating element of a coffee maker is not visible. So, mineral buildup often goes unnoticed for several months. The Keurig K-Duo user manual recommends descaling the coffee maker every 3 to 6 months to keep it in excellent working condition. The exact frequency can be decided based on the mineral content of the water you have been using and how many coffees you make
We err on the side of caution as many towns in the USA, in particular, have quite hard water and suggest descaling the machine every three months or 300 coffees – whichever comes first. This aligns with the best practice for Nespresso machines too.
That means if you use your machine often you may need to descale more frequently. Some examples of descaling frequencies are shown in the table below.
Number of coffees per day
Recommended Keurig K-Duodescaling frequency
1-2
Every 3 months
3-4
Every 3 months
5-8
Every 2 months
8-10
Every month
The frequency of descaling also largely depends on what is known as your ‘water hardness’ – which essentially means how much mineral salts are present in your town or city’s water supply. Areas with high water hardness will require you to descale your machine more often, and areas with low water hardness can reduce the amount of maintenance required.
Some models of Keurig machines have a warning light that will turn orange to alert you that the machine needs to be descaled.
In the case of the Keurig K-Duo, the touch screen will report the message “Time to descale the brewer!”
You’ll also want to regularly replace the Keurig water filter unit. Skip to THIS SECTION if you want to find out how to do that
To descale your Keurig Duo, you’ll need a descaling solution kit. A bottle of descaler that works for all machines costs about $15 from the Keurig website but only contains enough for 1 descaling cycle. ,
NOTE: Check whether there is any beverage pod in the K-Cup pod holder. You should remove it before descaling. You should also remove the water filter too or replace it with a new one at the end of the descaling process.
A Step-By-Step Guide On How To Descale Your Keurig K-Duo Coffee Machine
Use a wet cloth with a small amount of detergent to wipe down the body of the machine. It’s important not to wash the machine in the sink, as water can get inside and damage the electronics as well as cause rust.
Keeping the exterior of the machine clean from just, grime and greasy build-up is essential to stop dirt from getting into the machine.
Step 2: Descaling Solution Rinse
Nest we need to mix up the descaling solution and run it through the machine.
If you’re using a Keurig water filter, remove it before proceeding. It’s a good opportunity to also replace the filter while you do your descaling run.
Fill the water reservoir with a mix of descaling solution and water. If you’re using the Keurig descaler, use one bottle of descaler, and then refill with one bottle of water to achieve a 1:1 ratio. If you’re using another descaler, then follow the instructions on the back.
Plug the machine in, and ensure the machine is powered
Ensure there is no capsule in the machine. lower the handle and DO NOT insert a capsule into the machine.
With a mug inserted onto the drip tray, press the ‘POWER’ button, then select ‘POD’, press ’12’, and then hit the ‘BREW’ button. This will rinse the pod mechanism
Once complete, discard the contents of the collection mug down the sink
Next, insert the carafe into the machine onto the hotplate
Press the ‘CARAFE’ button, then select ’12’ and then press ‘BREW’.
Press the ‘POWER’ button to turn off the hot plate (we don’t need to heat the carafe!)
Let the brewer stand for 30 minutes to allow the descaling fluid to take effect.
Step 3: Fresh Water Rinse
The next step is to rinse out any remaining descaling solution from the water reservoir.
Then, pour fresh water into the reservoir until the water level reaches the MAX FILL line.
Return the empty collection mug onto the drip tray.
Run a ‘Pod Rinse’ bypressing the ‘POWER’ button, then select ‘POD’, press ’12’, and then hit the ‘BREW’ button. This will rinse the pod mechanism
Empty the contents collected in the mug into the sink.
Repeat steps 4 and 5 at least 3 times to ensure the machine is thouroughly rinsed, for a total of 4 rinse cycles.
Run a ‘Carafe Rinse’ bypressing the ‘CARAFE’ button, thenselect ’12’and thenpress ‘BREW’.
Empty the contents collected in the mug into the sink.
Repeat steps 7 and 8 at least 3 times to ensure the machine is thouroughly rinsed, for a total of 4 rinse cycles. Note: you may need to top up the water reservoir in this time.
The descaling is now complete. Reinsert the filter cartridge if you had removed it at the start of the process.
Download: Get a copy of our descaling cheatsheet below.
These are three steps you need to follow to descale your Keurig K-Duo coffee machine. There’s also this video below from the Keurig youtube channel to help visualize the process!
How To Replace The Water Filter On Your Keurig K-Duo Machine
Your Keurig coffee machine also has a small carbon water filter cartridge that has the purpose of removing impurities from the water that comes out of the water reservoir.
The Keurig K-Duo user manual recommends replacing these every 2 months, although we find it easier to do it every time we descale the machine.
What You’ll Need:
To get started, you’ll need to get a pack of replacement water filters.
Keurig also sells this cleaning kit which comes with 2 filter cartridges, 4 rise pods, and a bottle of descaler. This is convenient if you want to just buy one thing, but we don’t ever use the rinse pods and think you get better value by buying the filter cartridges and the Eco Descaler separately.
You’ll also need, a glass of water (to soak the filter cartridge)
How to replace the filter pod:
[Time Required: 6 Minutes]
It’s really simple to swap out a filter cartridge.
Take the filer out of its package and place it in a glass of water for 5 minutes to soak.
While it’s soaking, remove the plastic filter unit from your Keurig K-Duo machine’s water reservoir. disassemble the unit and dispose of the old filter cartridge.
Rise the mesh filter in the base of the unit to clear out any debris that’s become lodged there.
After 5 minutes have passed, take the filter out of the water and give it a quick rinse under the faucet/tap to rinse off any filter material.
Finally, insert the filter back into the base of the plastic filter unit, and clip the unit back together. Inset this assembly back into your keurig’s water reservoir and you’re done!
This video from Keurig’s official Youtube channel shows exactly how.
Frequently Asked Questions And Issues:
Here are some of the issues you may experience while performing a descaling run:
Foam dispensation
Brewer not filling properly
can you use vinegar instead of descaling solution
What is descaling solution made from?
Can you make your own descaling solution?
Can I use any descaler in my Keurig K-Duo machine?
What happens if I don’t descale my coffee machine?
Is decaling soltion toxic
Can you descale with baking soda?
Q. Why is there foam coming out from the coffee machine?
When you perform this task, you may find foam coming out from the brewer due to the cleaning action of the descaling solution. Don’t panic. It is the aftereffect of the reaction between the descaling solution and mineral deposit.
Most descaling solutions use a concentrated food-safe acid as the active ingredient. In the case of the Eco Descaler we use, this is citric acid – so any foam or residue from the descaler is perfectly harmless in diluted quantities.
Q. Is Your Keurig not filling correctly?
When you descale a Keurig Keurig K-Duo machine with a higher calcium scale quantity, you may find the brewer not filling accurately after adding the descaling agent. This situation leads to ineffective scale removal. You may also hear the sound of air blowing out.
To address this issue, you must switch off and unplug the brewer. Then, you have to remove the descaling solution from the reservoir and clean it thoroughly. Water must be refilled before plugging and turning the power on. The next step is to repeat the Fresh Water Rinse cycle recommended in Step 3.
Under normal circumstances, the issue will be resolved. If you experience the same problem again, you must keep the brewer unplugged for half an hour before starting the rinsing task.
Q. Can you use vinegar instead of descaling solution?
Scientifically speaking, cleaning your Keurig machine with vinegar is almost exactly the same as with a commercial descaler solution.
Unfortunately, however, vinegar tends to peel off the scale build up in flakes which could clog your machine causing irreparable damage. We’ve heard numerous cases of people having to throw out their coffee machine because of this. We’d recommend sticking with a commercial descaling product.
Q. What is a descaling solution made of?
Descaling solution is generally an acidic chemical that is capable of dissolving mineral salts such as oxides and carbonates. Notable descaling agents include acetic acid, citric acid, and lactic acid. These are all food-safe chemicals, however citric and acetic acid do impart a more noticeable taste to the machine, thus lactic acid is typically preferred.
Q. Can you make your own descaling solution?
You can make your own descaling solution using vinegar or citric acid, though we’d recommend using a commercial descaling product in a concentration that is proven not to damage your machine.
Q. Can I use any descaler in my K-Duo Machine?
Yes, in fact, you can use all descaling products in any brand of coffee machine. Just make sure to read the machine’s specific descaling instructions to make sure you use the correct amount of product.
Q. What happens if you don’t descale your coffee machine?
Scale builds up inside the pipes restricting the flow of water. If this happens inside the heating element it prevents water from reaching its optimal brewing temperature. When this happens it’s impossible to extract the full flavor from the coffee pods and the flavor will become weak. Severe scale buildup can clog water flow completely, causing a machine to stop working.
Q. Is descaling solution toxic?
Our favorite Eco Descaler descaling powder is completely non-tox and eco-friendly. It’s made from citric acid which is food safe in moderate doses. Other descaling solutions may use caustic chemicals such as sodium hydroxide which is highly toxic, so please check the label if unsure.
Q. Can you descale with baking soda?
We don’t recommend using baking soda to descale your coffee machine.
Q. How do you clear the descaling light on the Keurig K-Duo machine when it’s stuck on?
Some users have reported an issue where the light indicating that descaling is required becomes illuminated, and won’t clear automatically when you run a descaling cycle – no matter how many times you try.
If this happens to you, try pressing and holding the “8” and “10” buttons simultaneously for 3 seconds. This should force clear the warning.
Descaling the Keurig Duo takes around 75 minutes and consists of a descaling run and a rinse run.
You can use any brand of descaling product in your Duo, as long as you dilute it with the correct amount of water to the manufacturer’s instructions.
We recommend using the Green Pods Eco Descaler. It comes with 4 sachets (Typically 1 year’s supply) which are perfectly portioned. It’s environmentally friendly, and it’s also more cost-effective than the name-brand Keurig Descalers.
✔️ ENJOY BETTER TASTING COFFEE: Infrequent descaling is the #1 reason your coffee is tasting bad. Descale and you’ll taste the difference.
✔️ SAFE FOR YOU AND YOUR MACHINE: Our Eco Descaler is safe for all machine parts. It leaves no harmful residues and does not cause corrosion within the coffee machine.
✔️ WORKS ON ALL COFFEE MACHINES: Designed and tested on all leading coffee machines including Nespresso, Keurig, Dolce Gusto, Caffitaly, Breville, Delonghi, and more.
Tristan is a professional engineer and amateur coffee aficionado. He started The Green Pods when he saw just how much waste was being produced by the single-serve coffee machine market.
