Quick Answer: I wouldn’t recommend the Keurig Duo or the Keurig Duo Plus. If you want a dual K-cup and drip coffee maker, I’d instead recommend the Ninja DualBrew Pro.
This is my comparison of the Keurig Duo vs Duo Plus.
I own or rather used to own, the Keurig Duo. The machine hardly ever dispensed the correct amount of coffee in its carafe side, with servings of carafe coffee gradually getting smaller and smaller.
Its carafe side was basically unusable within six months of my buying it. It was a waste of money.
To see whether the Keurig Duo Plus is a better option than the K Duo, I’m going to answer the following:
- Whether the Keurig Duo Plus’s carafe side pump is more reliable than the Duo’s (if not then you should just avoid both products entirely).
- Whether the Keurig K Duo Plus’s thermal carafe and pitcher-style reservoir makes it a more user-friendly machine than the K Duo?
- If the answer to both these questions is no, then whether there are any dual-brew coffee makers worth buying?
Should I Buy the Keurig Duo or the Duo Plus?
I wouldn’t recommend buying the Keurig Duo or the Keurig Duo Plus.
Both machines have poorly manufactured carafe side pumps which makes the machines really unreliable.
In particular, their serving sizes of carafe coffee are really unpredictable and rarely bear much resemblance to what you program.
In fairness to Keurig, most dual K-cup and drip coffee brewers (Keurig manufactured or otherwise) are crap.
I think fitting two pumps in one machine (without making it ridiculously expensive) is just difficult.
By far the best dual coffee maker is the Ninja CFP307 DualBrew Pro.
It’s more expensive than the Keurig Duo Plus, but it more than makes up for it with its reliability.
Unlike Keurig’s dual coffee makers, you’re not likely going to have to replace the Ninja DualBrew Pro within a couple of years of ownership.
What Are the Differences Between the Keurig Duo and Keurig Duo Plus?
Here are the following differences between the Keurig Duo and Duo Plus:
Keurig Duo Plus Has a Stainless Steel Thermal Carafe; the Keurig Duo has a Glass Carafe
While I generally prefer thermal carafes to glass carafes (not least because I’m clumsy and have smashed the latter in the past), I actually think that the Keurig Duo’s carafe is a downgrade compared to the Duo’s glass carafe.
It’s impossible to pour from the Keurig Duo Plus’s thermal carafe without a lot of water dripping down the front of it. As this water runs down the carafe’s outer body, it’s going to end up on your floor or counter, not in your cup.
As one Amazon reviewer puts it:
Even otherwise positive reviews of the K Duo Plus complain about this, suggesting that it’s a problem affecting all units.
The Keurig Duo’s glass carafe is…fine. It’s not going to make a mess every time you pour from it, unlike the Duo Plus.
Winner: Keurig K Duo
The Keurig Duo Plus has a Pitcher Style Water Reservoir; the Duo has a Flatter Water Tank
The Keurig Duo Plus has a tall “pitcher” style reservoir with a handle. This sits atop a pad to the right of the machine. It can swivel to the back of the machine as well if this makes storage easier.
The Keurig Duo has a wider flatter reservoir that attaches by sliding down the back of the machine.
The Duo Plus’s water tank is much easier to fill and carry than the Duo’s.
The water reservoir design is one part of the machine where the Keurig Duo Plus is hands down better than the Keurig Duo.
Winner: Keurig Duo Plus
The Keurig Duo Plus is Two and a Half Inches Slimmer than the Keurig Duo
The Keurig Duo Plus saves these two and a half inches by having a single spout for both its carafe and single-serve coffee.
The two machines are also different shapes from each other. The Keurig Duo Plus is the same shape as the Keurig Supreme Plus (which I have).
Below is an image of my Keurig Duo and Keurig Supreme Plus so you can see how their shapes differ:
Winner: Keurig Duo Plus
The Keurig Duo Plus is Typical $30 – $60 More Expensive than the Keurig Duo
The prices of the two machines will vary online, but this is what I could find from digging around on Amazon, Walmart, and Keurig’s own website in March 2023.
Winner: Keurig Duo
What Are the Similarities Between the Keurig Duo and Keurig Duo Plus
Here are the similarities that the Keurig Duo and Keurig Duo Plus share:
They Both Make Coffee in the Same Way
The Keurig Duo and Duo Plus have identical brewing mechanisms, meaning that their coffee will taste the same.
Both have the same-sized brewing chamber (so have the same brewing ratios) and brew drip coffee for around one minute per cup.
They both include a “strong” button which allows them to brew a richer coffee by slowing down the brewing time. This “strong” brew option only affects the way that the two machines brew K-cup coffee.
The upshot of this is that if you only care about coffee quality, then you are better off with the Keurig Duo than the Keurig Duo Plus.
Don’t buy the Keurig Duo Plus assuming that it will make a better coffee than the K Duo because it’s a direct upgrade. Internally, the two machines are the same.
You can find out more about the Keurig Duo Plus in my Keurig K Duo Plus review.
They Both Offer the Same Serving Sizes
Both machines offer the following preset serving sizes:
- K-cup size: 6 oz, 8 oz, 10 oz, 12 oz
- Drip coffee side: 6 cups (30 oz), 8 cups (40 oz), 10 cups (50 oz) 12 cups (60 oz)
I don’t like that the two machines do not allow you to make small servings of drip coffee.
Their ground coffee chambers only hold enough ground coffee to make an 8-cup serving of coffee. If you brew a bigger serving than this the coffee comes out super watery (I talk about this in more depth in my Keurig Duo review).
I’d have hoped that Keurig would have spotted that this was an issue with the K Duo and rectified it with the K Duo Plus, but this has not happened.
Pretty much every other dual coffee maker on the market lets you choose your own serving size based on how much water you fill the machine with. This helps them overcome their often too-small brewing chambers as you can just brew smaller batches of coffee to prevent them from being watery.
It’s a shame that you cannot do this with either the Keurig Duo or K Duo Plus, and I think that it makes these machines two of the worst dual brewers on the market right now.
They both have Unreliable Pumps
Both machines have poorly designed pumping mechanisms on their carafe side. This gives the two machines the following technical issues:
- Serving sizes decreasing over time: By far the biggest technical issue I found with the machines was that their carafe side serving sizes decreased over time. These serving sizes get smaller and smaller until you can’t make carafe coffee with the machine at all. I had this problem with my Keurig Duo.
- Incorrect serving sizes on the carafe side: I saw a lot of Amazon reviewers complain that the machines’ output on the carafe side can be completely different from the serving size you select. One Amazon reviewer eloquently described the Keurig Duo Plus’s carafe serving sizes as “a crapshoot”.
- The machines constantly want to descale: The machines’ deteriorating pump makes them “think” that it has a limescale issue (they “think” that it cannot pump water because its pipes are clogged rather than there being an issue with the pump itself). They, therefore, stay in “descale mode” (even after descaling) and are unable to brew more coffee.
A former Keurig customer support representative said that Keurig’s dual brewers tend to succumb to technical issues more often than their other machines. Here is what she said, pulled from this thread:
These pump problems are by far the biggest reason why I think you should stay away from both the Keurig Duo and the Keurig Duo Plus.
Are There Different Models of the Keurig Duo?
Keurig currently manufactures three combination drip and K-cup brewers. As well as the Keurig Duo and the Keurig Duo Plus, Keurig also makes the Keurig K Duo Essentials.
The Keurig Duo Essentials is just the Keurig Duo, but without the “strong” button and with no 6 oz or 6 cups serving size.
The Keurig Duo Essentials offer 8 oz, 10 oz, and 12 oz servings on the K-cup side and 8 cup, 10 cups, and 12 cup servings on the carafe side.
The table below shows the differences in features between the Keurig Duo, Keurig Duo Plus, and Keurig Duo Essentials.
|Keurig Duo Plus
|Keurig Duo Essentials
Available serving sizes
6 oz/cup, 8 oz/cup, 10 oz/cup, 12 oz/cup
6 oz/cup, 8 oz/cup, 10 oz/cup, 12 oz/cup
8 oz/cup, 10 oz/cup, 12 oz/cup
Water tank type
Flat tank, attaches to back
Pitcher, attaches to side or back
Flat tank, attaches to back
You can find out more about these machines by reading my:
I really wouldn’t recommend the Keurig Duo Essentials, even if it is quite a bit cheaper than both the K Duo and K Duo Essentials.
The Duo Essentials will always make watery carafe coffee because its serving sizes are too large for its brew basket. Its lack of strong brew functionality also means its K-cup coffee is really weak too.
It’s just a poor machine all around, and far inferior to the cheaper Hamilton Beach Flexbrew.
Are There Any Good Dual Carafe and K-Cup Brewers?
The two best dual carafe and K-cup brewers are:
- Ninja CFP307 DualBrew Pro (overall best dual brewer)
- Hamilton Beach 49976 Flexbrew (best affordable dual brewer)
If you’d like to find out some more good dual K-cups and drip brewers then please see my roundup of the best dual brewers.
Ninja CFP307 DualBrew Pro (Overall Best Dual Brewer)
The Ninja DualBrew Pro is one of the few dual brewers that will likely last you upwards of three years of daily use.
Ninja has smartly realized that the complexities of fitting two separate pumping mechanisms in one system mean that you need to use superior parts than with a single K-cup or drip coffee maker.
Ninja uses these superior internal parts. The Ninja DualBrew Pro is therefore more expensive than other dual brewers but it will make up for this with its longevity.
I specifically recommend the CFP307 DualBrew model. Other Ninja DualBrew Pro models see you paying even more just to be able to make coffee types that they do not execute well (their terrible cold brew for example).
The Ninja CFP307 DualBrew Pro, therefore, gives you the best value for your money of all Ninja dual brewers.
You can find out more about how Ninja machines compare to Keurig in my comparison of Keurig vs Ninja.
Hamilton Beach 49976 FlexBrew (Best Affordable Dual Brewer)
The Hamilton Beach FlexBrew makes better coffee than the Keurig Duo and Duo Plus for two reasons:
- It easily allows you to make single servings with loose grounds: This larger ground coffee allowance on its single-serve side means you can actually make strong 10 oz and 12 oz coffees.
- You can make any serving size up to 60 oz on its carafe side: You can make fuller flavored carafe coffees when you brew smaller serving sizes. The Hamilton Beach FlexBrew allows you to do this whereas the Keurig Duo and Duo Plus have a minimum 30 oz serving size on their carafe side.
While the Hamilton Beach FlexBrew still has similar reliability issues as the Keurig Duo and Duo Plus, its relative affordability means that this is more forgivable.
The Keurig Duo is slightly better than the Duo Plus as the Duo Plus does next to nothing to justify its additional cost.
I do not recommend either machine, however. If you want a dual K-cup and drip brewer I would instead recommend the Ninja CFP307 DualBrew Pro.