Keurig Slim vs Mini Plus

This is my comparison of the Keurig K Slim vs K Mini Plus, two of Keurig’s more compact coffee machines.

I own the Keurig K Mini Plus and spent half a day looking at product demonstrations of the K Slim, speaking to Keurig’s customer support reps, and browsing Amazon reviews and the Keurig subreddit to put together this comparison.

With the two machines being a similar price to each other, let’s see which machine provides better value for money.

Keurig Slim vs Mini Plus: Which One Should I Purchase (Quick Answer)?

The Keurig K Mini Plus is a better coffee maker than the Keurig K Slim. The Mini Plus makes better coffee due to its inclusion of the “strong” button. Although new models of the Slim use multistream technology, I find that this still leads to poorer coffee than the Mini Plus can make with the strong button on. 

Although the Keurig K Slim does not make as good coffee as the Mini Plus, it does have a superior heating system, meaning that it can make several cups of coffee in quick succession without the brewing temperature dropping.

This means that the Keurig K Slim might be more suitable for office use where its ability to make several coffees quickly may be tested.

Overview of Products

The table below shows how the Keurig K Mini Plus and Slim differ:

AttributeKeurig K SlimKeurig K Mini Plus
Dimensions (height, width, depth)12.14 inches x 4.76 inches x 15.20 inches12.10 inches x 4.50 inches x 11.30 inches
Maximum lid-up height17.28 inches16.80 inches
Mug clearance (drip tray removed)6.00 inches (7.00 inches)6.00 inches (7.00 inches)
Reservoir size48 oz (stores water)12 oz (fresh water each time)
Serving sizes8 oz, 10 oz, 12 ozUses all water in reservoir each time
Strong buttonNoYes
Multistream technologyYesNo
Altitude modeYesNo
Descale modeYesNo

The Keurig K Slim has several features and automation that the Mini Plus does not have.

These include:

  • The addition of a larger reservoir that stores water for later use
  • Preprogrammed serving sizes
  • The addition of an altitude mode (which brews the coffee at a slightly lower temperature) and a descaling mode (which forces the machine to brew a 12 oz serving in order to descale it).

In my opinion, these additional features and automation do not actually improve the quality of coffee or the usability of the Keurig K Slim compared to the Keurig Mini Plus. If anything they detract from the machine, rather than improve it.

Let’s have a closer look at how these features affect the way the two coffee machines work and the quality of coffee that they produce.

Quality of Coffee

The Keurig K Mini Plus makes better coffee than the Keurig K Slim. This is in part because the Mini Plus’s “strong” button creates a stronger brew than the Slim’s multistream technology, but also because the Slim does not allow you to brew a coffee smaller than eight ounces.

Standard-sized K cups hold enough coffee for a six-ounce serving, meaning that unless you purchase My K Cup Universal Reusable pods you will always get a watery coffee with the Slim.

The Sim and the Mini Plus try to achieve the best quality coffee in different ways. They are:

  • Keurig K Slim uses “multistream technology”: Multistream technology just means that the Slim punctures your K cup with five holes in the top, rather than one hole. This means that water has more entry points into the K cup so that all the coffee grounds in the K cup get evenly extracted.
  • Keurig K Mini Plus uses the “strong” button: The strong button brews coffee for about 20 seconds longer, increasing the Mini Plus’s brew time from around 50 seconds to 70 seconds. For reference, the Slim brews coffee for 40 seconds. As a general rule of thumb, the longer coffee brews for, the stronger and fuller-bodied it will be.

I tested the Keurig K Mini Plus with the “strong” button on against the Keurig K Supreme Plus (which also uses multistream technology) with the “strong” button off.

I found that the longer brewing time created by the “strong” button being on creates better coffee than multistream technology does without the “strong” button.

It follows that the Keurig K Mini Plus will make stronger, fuller-bodied coffee than the Keurig K Slim.

Another reason why the Keurig K Slim makes poorer coffee than the Keurig K Mini Plus is that the Slim has a minimum serving size of eight ounces.

K cups were designed to brew 6-ounce coffee servings. They only hold enough coffee ground in them to produce a decent strength coffee at 6-ounce servings. Therefore the Keurig K Slim will always produce a watery coffee when used with a standard-sized K cup.

Both the Keurig K Slim and K Mini Plus can take My K Cup Universal Reusable pods. These hold more coffee (enough for a decent 8-ounce serving size), so can salvage the poorer coffee made by the Slim.

Just remember to buy the multistream compatible My K Cup Universal Reusable pods if you have the Slim. These have five points of entry at the top to allow it to work in a multistream system.

Quality of Coffee Winner: Keurig K Mini Plus

It’s honestly a shocking design flaw that the Keurig K Slim both cannot make 6-ounce servings and has no strong button. It’s almost as if they designed it for people who like watery coffee.

Size and Aesthetics

The Keurig K Mini Plus is more compact than the Keurig Slim. Most of the difference in size between the two machines is found in the machine’s depth, with the Slim being 4 inches deeper than the Mini Plus. In terms of height and width, there is very little in it between the two machines. The Mini Plus is also available in a wider range of colors than the Slim.


Both the Mini Plus and the Slim were designed with saving space in mind.

The machines are two of the slimmest K cup coffee machines on the market (both Keurig and non-Keurig machines) having a width of 4.5 inches (Mini Plus) and 4.76 inches (Slim).

The main difference between the two machines, as far as size goes, is in the depth of the machine. The Keurig K Slim is around four inches deeper than the Mini Plus (15.20 inches vs 11.30 inches). This extra depth is to accommodate the larger reservoir at the back of the machine.

The additional depth of the Slim means that it will jut out further forward on your counter. This can limit the amount of forwarding countertop space that you have for food preparation.

You should bear in mind that although the Keurig K Slim and Mini Plus are advertised as Keurig’s most compact machines, neither are significantly smaller in height than other Keurig machines.

Therefore, if you have low kitchen cabinets then both the Slim and Mini Plus still may not fit under them.

Keurig Mini Plus with lids up
All Keurig coffee machines have a maximum lid-up height between 16.80 and 17.50 inches (pictured: Keurig Mini Plus)

Available Colors

The Keurig K Mini Plus is available in seven different colors, you can find this below (you can also get it white which I have not included).

The Keurig K Slim is available in three colours, you can find these below:

Size and aesthetics Winner: Keurig Mini Plus

The Keurig K Mini Plus wins this due to its more compact size and a wider range of available colors. The Oasis color seems particularly popular among Keurig’s customers and it’s a shame that the Slim is not available in this color.

Ease of Use

The Keurig K Slim automates the coffee-making process far more than the Mini Plus. Although this creates poorer-tasting coffee, it does make the Slim easier to use than the Mini Plus. The Slim also has a superior heating element compared to the Mini Plus, which makes the Slim much better at brewing multiple cups of coffee in succession.

Ease of Loading the Machine with Coffee and Water

The Keurig Slim is an easier machine to load up with coffee and water, mainly due to its larger reservoir capacity and ability to store water in its reservoir between brews.

The Keurig Slim has a 48 oz reservoir tank (this holds enough water for six of the machine’s smallest coffees). This gives you one less step in loading up the coffee machine compared to the Keurig K Mini Plus which requires fresh water for each brew.

The Keurig Slim’s reservoir attaches to the back of the machine and is easy enough to remove/reattach even when it is full to its capacity. 

The only time that removing/reattaching the Slim’s reservoir might be tricky is if you do not have much clearance space between the machine and your cabinets above it. If this is the case then it might be easier to just fill up the Slim’s reservoir with a jug, rather than removing it.

Although the Keurig Mini Plus’s reservoir is removable, it is so wide and shallow that it is hard to carry when full without spilling water everywhere. Therefore I prefer to just keep the reservoir attached to the machine and fill it up with a jug. 

The measurements on the Mini Plus’s reservoir are not that easy to read, making it hard to measure out serving sizes. Since the Slim has preprogrammed serving sizes, this is not an issue.

The Mini’s reservoir is precarious to carry when full of water

Ease of Programming the Machine to Make Coffee

Despite the Keurig K Slim’s additional functionalities over the Mini Plus, the two machines are equally as easy to programme.

Keurig does a fantastic job of making their machines easy to program, regardless of how complex their functionalities are.

They do this by always making sure that each function has its own dedicated button, that these buttons are well labelled, and that “eligible” buttons flash during each stage of the programming progress.

I can’t see anyone having a problem with programming either machine to make the coffee that they want.

General User Experience

The Keurig Slim has a more powerful heating element than the Mini Plus.

This means that the Slim can make coffees about twice as fast as the Mini Plus. The Slim is also significantly less noisy than the Mini Plus.

The Slim can also make several cups of coffee in a row much faster than the Mini Plus (again, because of this improved heating element). The Slim may well, therefore, be more suited to an office environment than the Mini Plus.

Ease of Use Winner: Keurig K Slim

The Keurig K Slim is a fair bit easier to use than the Mini Plus because of its larger capacity reservoir, preprogrammed serving sizes and improved heating function. That being said, the additional automation on the Slim does reduce the quality of coffee that you can make, mainly because it does not allow you to brew a 6-ounce cup of coffee.

Ease of Cleaning

The Keurig Slim’s larger reservoir and multistream functionality makes it harder to clean than the Keurig K Mini Plus. The multistream functionality can make a big mess in the port and the port holder, meaning that you need to clean the inside of the Slim much more regularly than the Mini Plus.

Cleaning the Reservoir

The reservoirs of Keurig machines have two parts that need to be cleaned.

Firstly the body of the reservoir needs to be cleaned about once every two weeks as grime can build up on its inner surface.

Secondly, the valve and filter of the reservoir (the small hole where water drains into the machine) need to be deep cleaned with a needle (or a straightened-out paperclip). Grime can deposit there and damage the water pump in the machine.

Both the Keurig K Slim and Mini Plus have removable reservoirs, making them easy to sponge down.

Cleaning Keurig K Mini Plus reservoir
Sponging down the Keurig K Mini Plus’s reservoir

The tallness of the Slim’s reservoir means that deep cleaning its valve is trickier than the Keurig Mini Plus. 

To clean the valve of the Keurig Slim you need to get your arm all the way into the bottom of the tall, thin reservoir. It’s not that easy to do this and still have fine control over what you are doing when cleaning the valve. You also cannot see where the grime is depositing in the valve, which only makes things harder.

As the Keurig K Mini Plus’s reservoir is small and wide, it is much easier to deep clean the valve as you can easily access it and see what you are doing throughout the cleaning process.

Cleaning the K Cup Port

Both machines have removable K cup ports that can be cleaned in the sink. The part of the machine where the K cup port sits should also be cleaned when the K cup port is removed as coffee liquid and granules can spill into here.

Although you clean the K cup pods of both machines in the same way, the multistream functionality on the Slim leads to you needing to clean the K cup ports more often than with the Mini Plus.

Having five points of entry for water into the K cup means that much more coffee is spilled into the K cup port and machine every time you make a coffee. I need to clean the inside of my Keurig K Supreme Plus (which also has multistream) after roughly every 10 coffees. This is about three times as often as I need to clean the K cup port of my Mini Plus.

Descaling the Machine

Both machines are descaled in the same way. The only difference is that the Keurig K Slim tells you when it needs to be descaled (the descale button starts flashing when this is the case) whereas the Mini Plus does not.

I like Keurig K Slim tells you when it needs to be descaled as the regularity in which a machine needs to be descaled depends on the mineral content of the water that you use in it.

Descaling your machine exactly when it needs to be done could add to its longevity and the descale warning on the Slim helps you make this happen.

Ease of Cleaning Winner: Keurig K Mini Plus

Although the two machines are similar in their ease of cleaning, the Keurig K Slim’s multistream functionality means you have to clean it much more often than the Keurig K Mini Plus.

Final Verdict

The Keurig K Mini Plus is a better coffee maker than the K Slim. 

Keurig made two huge mistakes with the Slim, namely their exclusion of the “strong” button and having the machine produce a minimum serving size of 8 ounces. This means that the machine is incapable of making a decent-strength coffee with standard K cups.

The Keurig Mini Plus has everything you need for a compact single-serve coffee maker. While its coffee will not knock your socks off, its “strong” button means it can produce decent strength coffee up to 8 ounces with a standard K cup and up to 10 ounces with a My K Cup Universal Reusable pod.

One advantage that the Slim has over the Mini Plus is its ability to brew multiple cups in quick succession. This, combined with the larger storage reservoir means that it may be more suitable for office use than the Mini Plus.

For more information on the Keurig Mini Plus, please see my comparison of the Keurig Mini vs Mini Plus.

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