I’ve purchased, owned, and used both the K-Slim and the two different versions of the K-Mini, the regular Mini and the Plus version. Not only have I used all three of these machines but I’ve collectively brewed at least 500 k-cups in these machines combined…so I know how they work and how they differ.
Today I want to share with you what I’ve learned about each of these Keurig K-Cup coffee makers and give you advice on which one to choose.
There are actually a number of differences between these machines but only a few main differences that are actually important. To start this article off I’d like to first summarize only the important differences right off the bat.
The K-Slim has a small 36oz detachable water reservoir in the rear compared to a single cup reservoir in the upper rear of the K-Mini and the K-Mini Plus. The K-Mini will brew all of the water placed in the reservoir, regardless of how much is used, while the K-Slim will only pull 8, 10, or 12oz of water from it’s water tank based on which cup-size selection you press. Only the K-Mini Plus offers a “Strong” button that slows the brew process down a bit so that the brewed coffee tastes better.
Of these three brewers I’ve included the K-Slim on my list of best entry level (cheap) units and the K-Mini Plus on my list of “best for your money” units. You can see the entire list of best Keurig coffee makers here.
Which Do I Recommend?
Of these two models I recommend most people to opt for the K-Mini Plus if you can afford the slight increase in cost but if you can’t then opt for the K-Slim over the base model K-Mini; it’s cheaper and although it doesn’t make the best coffee it will still give you a cup first thing in the morning in less than a minute.
You can see one of the best deals ever on the K-Mini Plus right here or this Cyber monday / cyber week deal on the K-Slim here.
URGENT UPDATE – There is a new option to the SLIM that was released in 2022. You can now pick up a K-Slim +ICED which upgrades the unit to a hot coffee / cold coffee k-cup brewer. Unless you are in the market for a dedicated iced coffee brewing option the Slim Iced version is being heavily marketed this year as we push in to the 2023 shopping season.
► You can see the best places to buy the K-Slim here and the best places to buy the K-Mini Plus here.
In addition to the few important differences summarized above they are also the minor differences.
These minor differences will probably only be important to a small number of people that that are shopping for entry level Keurig machines.
Further into this article I’ll cover minor differences such as dimensions, the time required to brew a cup of coffee, the brew size selections, and the temperature of the coffee when it gets to your cup just to name a few.
Better Alternatives To The K-Slim & K-Mini
For most people considering the K-Slim I suggest looking at the K-Express as a better option and for those considering the K-Mini for it’s smaller size I find the K-Compact is a nice alternative because it’s still small but can hold 3-4 cups of water in it’s reservoir.
Here are my comparison articles for those machines:
► K-Mini (Plus) vs K-Compact
► K-Slim vs K-Express
But first I made a video comparing these two machines that I want to show you. It should address a lot of your questions and then after the video we’ll get more granular.
Does The K-Mini or K-Slim Make Better Coffee?
If you want to compare these machines based solely on their ability to make good coffee then your best bet will be the K-Mini Plus, followed by the K-Mini. The K-Slim simply doesn’t have the ability to make very good coffee under any circumstances.
The vast majority of k-cups start producing pretty week coffee as your cup size gets to 8-ounces and above but the K-Slim doesn’t give you the option to brew anything smaller than an eight ounce cup so you will always get somewhat weak coffee out of it.
The two K-Mini’s however are designed to be water-in-water-out systems so if you put 6.5 ounces into the reservoir then that’s how much coffee your machine will make. You can make anything between six and twelve ounces of coffee and for me I like brewing about 7oz cups out of my machines as this gives me a slightly bigger cup while minimizing the watering down effect of using too much water.
Of the two K-Mini machines the K-Mini Plus offers a “Strong” button which is why I say it will make the best tasting coffee of the three machines. The strong button will slow the flow of water through the k-cup giving you a more complete flavor extraction. When you use this setting your coffee brews slightly slower but most people won’t notice the extra 20 seconds of wait time although they will probably notice the flavor of their coffee is more complex and complete.
Of course the K-Mini Plus is the more expensive of the three units but by a lot and I think the higher quality of brew is worth the extra bit of money you’ll spend on it.
Make sure to see this post for all of my K-cup coffee maker reviews and this post to learn what the strong button does.
Is The K-Mini Smaller Than The K-Slim?
If size and shape is a big deal for you then you will also find the K-Mini to be a better machine for you because it does take up less space.
The K-Slim and K-Mini are exactly the same width so they will both take up the same lateral width on your countertop but because the K-Slim gives you a multi-cup refillable water reservoir that is placed in the back of the unit the extra depth is noticeable – it will stick out further on your counter which may be problematic if you only have limited counterspace in your kitchen for actual food prep.
If size is your biggest concern then you should note that both of these units are big compared to some of the smaller options out there by different companies. I own and have reviewed almost all of the smallest k-cup coffee makers here for your convenience.
The Water Reservoirs Are Very Different Too
Both the K-Slim and the K-Mini Plus have water reservoirs that can be removed from the unit. This makes it possible to wash them out at the sink or in the dishwasher and they can be filled at the sink too.
In contrast the basic K-Mini features a non-removable reservoir meaning you have to bring water to the machine to fill it up (usually this will be your coffee mug) but this also means it’s very hard to clean out the reservoir if any debris gets into it.
Both the K-Mini and the K-Mini Plus have a small mesh filter screen at the bottom of the reservoir which stops large particles of dust, hair, or other debris from entering the machine. The screens need to be cleaned periodically and the basic K-Mini just makes it hard.
You can put anywhere from 6 to 12 ounces of water in the K-Mini’s reservoirs for brewing and cleaning but of course the K-Slim’s best feature is it’s larger reservoir that can hold multiple cups of water at a time. From my experimentation I can get about three 8-ounce cups of coffee brewed from one full reservoir on the K-Slim, about a day’s worth of coffee for me.
The reservoir is small compared to other Keurig reservoir brewers but certainly bigger than the K-Mini or the K-Mini Plus.
How Fast Does The K-Slim Brew Compared To The Mini?
The K-Slim brews a cup of coffee in just over 30 seconds from when you hit the brew button compared to around 45-seconds for the K-Mini. If you use the strong button on the K-Mini Plus this will extend it’s brew cycle to around 70 seconds which is slower but the extra brew time does make your coffee taste better.
Which Machine Brews The Hottest Coffee?
The K-Mini and K-Mini Plus both seem to brew slightly hotter coffee based on my thermometer readings from the cup however the differences is so small that no one is likely to tell the difference.
Which Is Best: The K-Slim, The K-Mini, Or The K-Mini Plus
The K-Mini Plus is easily the best unit of these three because of it’s strong button that allows for a full bodied cup of coffee. It also gives you the ability to brew any size cup you want between 6 and 12 ounces. I prefer brewing 7-ounce cups.
Click here to see the best places to buy the K-Mini Plus.
Between the two entry level units I think the plain K-Mini is better than the K-Slim because it also gives you full cup size customization and brews slightly slower however some people really prefer water reservoirs and if you buy the K-Slim you get a small reservoir that can even accept a charcoal water filter if you choose to buy one separately so this could be considered better by some.
Here are a couple links you can use to see my recommendations for best places to buy the K-Mini or the K-Slim.
If You Like The K-Slim or K-Mini Than See These Head-To-Head Comparisons
► K-Mini vs K-Mini Plus
► K-Mini vs K-Express
► Difference Between K-Compact, K-Classic, and K-Select
Are Cheap Keurig Coffee Makers Worth Buying At All
One thing I’ve failed to discuss in this article to this point is where or not either of these machines actually make good coffee in the first place.
For one I have an article all about this topic that I think you should read: Does Keurig Make Good Coffee At All?
In that article I make the case that Keurig coffee is good enough if you stick with machines that have a strong option to brew slower and if you stick to the smaller brew sizes on your machine of choice.
Here are a list of k-cup brewers that have a strong button and here are a couple Keurig’s, the K-Select and the K-Elite, that I compared that both have small cup sizes available.
Keurig coffee is also going to taste better if you can keep your machine cleaner. I have a full guide to preventing clogs in your Keurig here and I would be failing you if I didn’t mention the fact that the K-Slim is easier to keep clean than the K-Mini or the K-Mini Plus due to it’s removable water reservoir and it’s ability to accept a charcoal water filter if you choose to buy one separately.
From just the K-Slim and the Minis if I were to buy one today or recommend someone which one to buy I’d say the K-Mini Plus without hesitation simply due to size and quality of coffee brewed relative to it’s price point.
You can find out the best place to buy the K-Mini Plus here.
I Have More To say About The Other Keurigs
Below I’ve listed some further reading to help you better understand which Keurig is best for you and how they are all different. Choose an article from this list that looks interesting and keep learning.
► Do Travel Mugs Fit Under Keurig Coffee Makers
► Keurig K-Duo vs K-Duo Plus vs K-Duo Essentials
► Keurig vs Cuisinart
► Best Biodegradable & Compostable K-Cup
► Difference Between The K-Supreme Plus & K-Supreme Plus SMART
► K-Elite vs K-Supreme
► Keurig K-Café vs Nespresso Vertuo Plus
► Keurig K-Supreme Plus SMART Review
► K-Café vs K-Latté