This is my Keurig K-Duo Review. The Keurig Duo is Keurig’s attempt at a combination drip coffee machine and single serve K cup coffee maker.
I bought the Keurig K Duo and spent two days testing it out, as well as looking at reports from other owners on YouTube and the surprisingly active Keurig subreddit, to put together the most comprehensive review of this coffee maker online.
Overall, I found that the Keurig K-Duo was good at making single-serve pod coffees but produced a subpar drip coffee.
The machine is also let down by its poor design and build quality meaning that it is prone to leaking in several places and often succumbs to technical issues within its first year of ownership.
That being said, its ability to be configured in advance and ability to keep drip coffee warm in the pot for several hours does give it the hands-off convenience suitable for families of drip coffee drinkers and small offices.
Overview of the Keurig K-Duo
The Keurig K-Duo is one of Keurig’s three coffee machines (along with the Duo Plus and Duo Essentials) that can make drip coffee along with single serve coffee using K cups.
The machine has two dispensers, one dedicated to drip coffee on the left, and the other dedicated to single serve coffee on the right. This does significantly increase the Keurig K-Duo’s width compared to other Keurig machines.
You can find the dimensions of the Keurig K-Duo below:
The height of the Keurig K-Duo is a bit of a problem as you have to lean over the machine to remove the reservoir to fill it up. This is difficult to do if there is not much clearance space between the top of the machine and your cabinets above it.
Since the machine cannot make a drip coffee and a filter coffee at the same time, it does leave you wondering why the Keurig K-Duo does not save space by just having one dispenser.
The machine was very easy to set up, and I was able to make coffee within ten minutes of unboxing the machine. The button control panel was super intuitive especially considering the large number of brewing options available to you.
Keurig K-Duo’s Highlights
The machine has a “strong” button that allows you to brew single serve coffees for 25% longer. This made a noticeable difference to the depth of flavor of your pod coffees, and I would now argue that this feature is a must have on any K cup coffee maker.
It has a hotplate to keep your drip coffee hot. This hotplate stayed on for two hours after the drip coffee was brewed. This could be a Godsend for people who don’t like making filter coffee in a French Press because it does not stay hot for long enough.
Keurig K-Duo’s Lowlights
Poor design and build quality. The machine leaked from several places, making it hard to use without needing to clean up spilled coffee or water afterwards. The machine simply did not feel like it was built to last, and this feeling has been backed up by the large number of technical issues that its users report online.
It makes weak coffee when programmed for larger servings. The machine struggled to make coffee of sufficient strength when making a 12 oz single serve or more than 10 cups of filter coffee.
Overall I would not recommend this product. The drip coffee that it produces is poor, and although it can make good single serves, you are better off buying smaller Keurig machines such as the Mini Plus or Keurig Supreme.
Features and Functionalities of the Keurig K-Duo
As stated earlier the Keurig K-Duo can make both single serve coffee using K cups and drip coffee from coffee grounds.
The machine has a wide array of functionalities that allow you to customize when and how these two types of coffee are made. I will break down what these are according to the type of coffee that they apply to:
Single Serve K-Cup Coffee
Serving sizes: The Keurig K-Duo allows you to make K cup coffees in 6 oz, 8 oz, 10 oz and 12 oz servings.
“Strong” setting: This lengthens the brew time of single serve coffees by 25%. The difference in strength was noticeable in a blind tasting that I held with my housemates. The strong setting does a lot to counteract the common complaint that coffees made from K cups are too watery. The difference is particularly noticeable with 6 oz and 8 oz coffees.
Drip Coffee
Serving sizes: You can make drip coffees of 6 cups, 8 cups, 10 cups and 12 cups. Bear in mind that cups here refer to 5 ounces of coffee. I prefer to drink a 10 ounce cup of coffee (for context this is the size of a Tall coffee at Starbucks) so in reality you can half the amount of cups that the Keurig K-Duo tells you that you are brewing to work out serving sizes.
Pause and Pour: While your drip coffee is brewing you can press the brew button at any time to pause the brewing process in 20 seconds. This gives you full control over the amount of coffee that you make. The number of cups you set at the start just tells the machine when to stop brewing.
Auto brew: The Keurig K-Duo allows you to set up a time for your drip coffee to start being made up to 24 hours in advance. This is a fantastic timesaver in the mornings.
Below you can find a table comparing the features of the Keurig K-Duo to Keurig’s two other drip coffee/single serve combination coffee machines: the Keurig K-Duo Essentials and the Keurig K-Duo Plus.
| Machine | Keurig Duo Essentials | Keurig Duo | Keurig Duo Plus |
| Dimensions (Height, Width, Depth) | 12.74 inches x 12.27 inches x 13.44 inches | 12.92 inches x 10.94 inches x 12.76 inches | 14.90 inches x 7.68 inches x 15.88 inches |
| Maximum height with lid up | 16.80 inches | 16.90 inches | 17.50 inches |
| Maximum mug clearance (drip tray removed) | 6.5 inches (7.5 inches) | 6.25 inches (7.25 inches) | 7 inches (8 inches) |
| Serving sizes | 8-12 oz K cup; 8-12 cup drip coffee | 6-12 oz K cup; 6-12 cup filter coffee | 6-12 oz K cup; 6-12 cup filter coffee |
| “Strong” button | No | Yes | Yes |
| Auto brew | Yes | Yes | Yes |
How Good is the Coffee Produced by the Keurig K-Duo?
Since the quality of coffee produced by the single serve and drip coffee sides of the machine is markedly different, I’ll review them separately.
Single Serve Coffee
The Keurig K-Duo produces a good single serve coffee only if you brew a 6 oz or 8 oz cup and use the “strong” button.
Ten and twelve ounce single serve coffees come out too weak even when the “strong” button is used. This is not necessarily the fault of the machine, but rather a function of the K cups themselves.
K cups only hold 10-11 grams of coffee. This is meant to be enough coffee for six ounces of water. K cups simply are not designed to make 10 oz and larger coffees.
The Keurig K-Duo is compatible with My K Cup Universal Reusable K cups that hold up to 17 grams of coffee grinds. Although I have not tried these, they should make a decent strength 10 oz coffee (if you use the “strong” button), but will probably still struggle with a 12 oz serving.
Drip Coffee
For drip coffee, let’s just say that the Keurig K-Duo is designed for maximising convenience over the quality of coffee produced.
The drip coffee produced in a Keurig K-Duo is far more water than similar coffee made in a French Press. This wateriness becomes more pronounced as the serving size increases.
My theory behind why this is is that the heating element in the machine does not heat the water up high enough for the water to extract the coffee properly.
Drip coffee should be brewed at around 205 degrees Fahrenheit, whereas tests on the Keurig K-Duo indicate that the coffee is brewed at closer to 180 degrees Fahrenheit. The more water that needs to be heated, the lower the maximum temperature it will reach, meaning that larger servings will turn out even weaker than smaller ones.
I’d therefore recommend that you do not brew more than 8 cups of coffee at a time with your Keurig K-Duo. Even then do not expect it to come close to a filter coffee that you get from a coffee shop or even one that you could make with a French Press or a pour over at home.
How Easy is the Keurig K-Duo to Use?
The Keurig K-Duo’s ease of use is the best thing about it. It is both easy to set up and program the type of coffee that you want.
Set-Up
It only took 10 minutes to get the Keurig K-Duo from unboxing to being able to make my first coffee.
All I had to do to set the Keurig K-Duo up was plug it in, fill the reservoir to its maximum capacity, turn it on and then have the machine produce a 12 oz single serve coffee without a K cup and one 12 cup drip coffee without any coffee grounds. This was to clean out the mechanism of any dust that may have collected in its inner pipes.
The only difficulty that I had when setting up the machine was filling up the reservoir.
Unfortunately, the Keurig K-Duo has a poorly designed reservoir in that it is very wide and thin, and only has about an inch of clearance between the maximum line and the top of the tank. This makes a full reservoir hard to carry without sloshing water everywhere.
The reservoir is also fitted to the back of the machine, meaning that you have to bend over to remove it or put it back in its place.
This is awkward because there is often very little clearance between the top of the machine and the bottom of your cabinets, so you either need to turn the machine around or try to put the reservoir in at an angle. This, again, can often lead to water being spilled on your machine and counter.
The machine came with all its removable parts attached in their rightful place, with the exception of the carafe which came in a separate box. All I had to do was slot the carafe under the drip coffee dispenser for the machine to be fully assembled.
The machine also came with an instruction manual that was pretty much useless, however the machine is so easy to set up and use that this did not really matter.
Programming Different Coffees
The Keurig K-Duo is programmed using a buttoned control panel. You can see an image of this below:
Here is what all the buttons do:
- The on/off button.
- Hour and minute button to set the time (time is shown on the screen). The Keurig K-Duo needs to “know” the time for its auto brew function.
- Sets the auto brew function. Once you press this button the machine will prompt you to set a time for the drip coffee to be made.
- Select serving size. The numbers correspond to ounces for single-serve coffees and cups (5 oz) for drip coffee
- Select drip coffee
- Select single serve
- Brew/pause brewing
- “Strong” button
Although there are a lot of different buttons, selecting the type of brew that you want is really easy thanks to the fact that the relevant buttons flash at every point of the programming process. You can find a demonstration of this in the video below:
How Easy is the Keurig K-Duo to Clean?
The Keurig K-Duo is a messy machine, plain and simple. The amount of cleanup that is required after every coffee that you make (especially so with drip coffees) is one of the worst things about the machine.
Below I have listed the parts of the machine that need to be cleaned, how to best clean each part, and how often each part needs to be cleaned.
Carafe Lid
Every time I made a drip coffee I found that a small amount of coffee leaked onto the lid of the carafe.
This meant that the lid of the carafe needed to be wiped down with a wet cloth after each use.
The lid of the carafe also leaked coffee whenever you poured a cup out meaning that my counter also needed a wipe after every coffee.
The inside of the carafe can be easily cleaned just by rinsing it with water after each use.
Removable Parts
The filter coffee port, K cup port, reservoir and drip trays are all removable and should be cleaned once a month. Unfortunately none of these are machine washable so need to be cleaned by hand.
The drip trays hold 8 ounces of liquid on each side and this means that they usually take about three weeks of daily use before they start overflowing.
K Cup Needles
The top needle that punctures the K cup can collect coffee residue around it and this can affect its ability to puncture pods.
You can clean this either by wiping it with a paper towel between your thumb and forefinger (be careful not to prick yourself) or by scraping it down with a straightened paperclip. This should be done every time you see residue around the needle.
The bottom needle on the Keurig K-Duo is in the K cup port and can therefore be removed and rinsed.
Descaling
The Keurig K-Duo will tell you when it needs descaling. The clock will say “descale” in its top left corner and it will not let you make another coffee until it has been descaled.
To descale simply fill the reservoir to its maximum capacity with two parts water and one part descaling solution, then run a 12 oz single serve and 12 cup drip coffee without any coffee grounds or K cups in the machine.
Overall the long term required maintenance of the machine was not too unreasonable although I was not happy with the fact that the machine spilled some coffee pretty much every time I used this.
This, combined with the poorly designed reservoir, made the Keurig K-Duo frustrating to use.
Are there any Known Issues with the Keurig K-Duo?
I scoured through Amazon reviews, the (surprisingly active) Keurig subreddit and the comments of YouTube videos about the Keurig K-Duo in a bit to find out whether there were any problems with the machine that got mentioned by users again and again.
My research revealed three common issues that Keurig K-Duo owners found with their machines. These are:
- The machine does not make the desired amount of filter coffee: Keurig K-Duo users often found that the machine made several fewer cups of coffee than what you set it to brew. This problem seemed to get worse as the machine got older. There was no obvious way of fixing this problem with users just having to put up with it and brew extra pots of coffee when needed.
- The Keurig K-Duo goes into descale mode far too often: Several users reported that their Keurig K-Duo goes into descale mode on a weekly basis, or just stays on descale mode completely. In descale mode, a machine can only make a 12 oz K cup or 12 cup drip coffee. Some users have reported that holding down the 8 and 10 button for five seconds while the machine is on fixes this problem, however other users claim that it does not.
- The 1r error code: This is where the Keurig K-Duo does not pump water and displays 1r in the top left corner of the clock. The 1r error refers to an error with the reservoir connecting to the machine. While it can be fixed by repositioning the reservoir and/or by cleaning the valves that connect the machine to the reservoir, it can sometimes also mean that the machine needs to be replaced.
Alternatives to the Keurig K- Duo
There are two machines that offer similar functionalities to the Keurig K-Duo but are better designed overall.
These are the Hamilton Beach Flexbrew and the Keurig K-Duo Plus.
Hamilton Beach Flexbrew
The Hamilton Beach Flexbrew is also a dual pod and drip coffee maker with the two types of coffee being made either side of each other.
The Hamilton Beach Flexbrew has the same functionalities as the Keurig K-Duo, including a strong setting, the ability to schedule brews and options to make up to 12 oz single-serve coffees and 12 cup drip coffees.
For me the Hamilton Beach Flexbrew edges the Keurig K-Duo because of its superior build quality. This makes it less susceptible to the technical issues that plague the Keurig K-Duo.
You can find more information about how these two machines stack up in my comparison of the Keurig Duo vs Hamilton Beach Flexbrew.
Keurig K-Duo Plus
The Keurig K-Duo Plus is Keurig’s upgrade of the Keurig K-Duo. Keurig made the following changes to the Keurig K-Duo when creating the Duo Plus:
- There is only one dispenser for both drip coffees and single-serve coffees. This means the Keurig K-Duo Plus is only around two-thirds as wide as the Keurig K-Duo
- The awkwardly shaped reservoir on the Keurig K-Duo has been replaced with an easy to use tall reservoir with a handle on the Duo Plus. This makes the Duo Plus much less messy to use than the Duo.
- The carafe has been redesigned. It is now made of metal to stay hotter for longer and the lid has been redesigned so it does not leak coffee when being poured.
- The Keurig K-Duo Plus has an extra three quarters of an inch of cup clearance compared to the Keurig K-Duo. This was because some users complained that they could not fit their travel mug in their Keurig K-Duo.
I’d say that Keurig did a good job in troubleshooting the worst problems with the Keurig K-Duo when making the Duo Plus and therefore the Duo Plus is worth the extra bit of money.
You can find out more about this machine by reading my Keurig Duo Plus review and my comparison between the Keurig K Duo and K Duo Plus
Conclusion: Poor Design and Build Quality Lets Down a Cool Idea
To reiterate: I would not recommend you buy the Keurig K-Duo.
The main reason why someone would want to buy a machine that produced both drip coffee and single serve coffee is convenience. However the amount of cleaning that this machine requires, and the sheer number of technical issues that it has negates any convenience that you might derive from it.
Keurig seems to have acknowledged their mistakes when making the Keurig K-Duo as evidenced by the fact that they rectified a lot of these with their Duo Plus.
I would therefore recommend either buying the Keurig K-Duo Plus or Hamilton Beach Flexbrew if you want a dual drip and single serve coffee maker.
If you want to find out more about the single serve coffee makers available to you, please find my verdict on the best coffee makers for K cups.
