Keurig Single Cup Coffee Maker
MINI Plus B31 Brewing System

Quick Look
Keurig B31 MINI Plus
Model B31

green check mark Most people like it!

3.9 out of 5 stars 3.9/5      527 reviews

between $50 and $100 $50 - $100 USD

The B31 MINI Plus Keurig single cup coffee maker is the least expensive in Keurig's line of brewing systems.

The MINI Plus differs from other Keurig models in that the water reservoir only holds enough for a single brew.

Owners sum it up:

This is an excellent little K-cup brewer for anyone that is looking for one for a dorm, an office cube, or for occasional use in the kitchen ..........C. L. Paul

You do have to do the steps in order or it does not work. It was a learning curve to get a cup of coffee every time ..........Jones

Product Details

Model B31

With a small footprint and very minimal cleanup, the MINI Plus is particularly appreciated in households with only a single coffee drinker.

Among those who were indecisive or hesitant, a popular sentiment is that they are thrilled with the purchase and sorry they didn't get it sooner.

Brewing is easy, with only a few steps.

However, the machine's design is such that the steps must be performed in a precise order. Despite blinking indicators on the front panel guiding through the steps, some consumers still struggle with the correct order.


K Cups in counter top holder

The patented single serving beverage packet used in all Keurig single cup coffee makers is called the K-Cup. There are over 200 varieties of K-Cups from which to choose, including teas, hot chocolate, and other beverages.

In addition, there are several ways to use your own ground coffee in these brewing systems.

Read more about K-Cups, K-Cup varieties, and using your own ground coffee in your Keurig single cup coffee maker

Brewing - How to Use the MINI Plus

Brewing consists of a few simple steps, and is finished in a little over two minutes.

Due to the design of this Keurig single cup coffee maker, those steps must be done in a precise order. Some find this a little challenging first thing in the morning.

Step 1:  After turning on the power, and with the K-Cup holder lid in the closed position, fill the water reservoir.

Keeping the K-Cup holder lid closed prevents the water from draining into the lower heating chamber, and allows you to accurately use the metered fill indicators on the reservoir. If you allow the reservoir to drain into the lower chamber while you are filling, it is easy to overfill.

adding water metered cup sizes
Step 1 - add water cup level indicator

Cup Size

Cup size affects the intensity of the flavor. It adds more or less water to the same amount of coffee.

To get a larger quantity of brew with the same intensity, you will have to brew more than one K-Cup.

Keurig recommends the use of bottled or filtered water.

The reservoir is metered for 3 cup sizes: 6 oz, 8 oz, and 10 oz. Any amount over the maximum 10 ounces will overflow into the drip tray.

Step 2:  Lift the brewer handle. This allows the water to drain from the reservoir into the heating chamber. It takes about 5 seconds to drain. If you close the brewer handle before draining is complete, you will end up with a short cup.

Step 3:  Insert a K-Cup, get your mug in place and lower the handle to close the K-Cup Holder lid.

left handle insert k-cup brew button
Step 2 - raise handle Step 3 - insert K-Cup and lower handle Step 4 - Press Brew button

Step 4:  The "brew" button should now be flashing blue, indicating you are ready to brew. Press the brew button to start.

The unit takes about two minutes to heat. Once heated, water is forced through the K-Cup and brewed coffee is dispensed. Brew temperature for this Keurig single cup coffee maker is set at 192°:F.


The reservoir on the MINI Plus is single use only - you must add water each time you brew. This means you must wait for it to heat up each time you brew, unlike other units that hold hot water as long as they are turned on.

removable drip tray
Removable drip tray with overfill indicator

The unit features a removable drip tray that catches overflow from the mug or from the cold water reservoir. Remove the tray to accommodate short travel mugs.

When the drip tray gets full, a red float ball pops up to remind you to empty the contents.

cord storage
Cord storage in the back

The electric cord can be fed into the back of the unit for storage.

The K-Cup holder and funnel are top-rack dishwasher safe, at low temperature.

The rest of the machine, including the reservoir, drip tray and drip tray plate must be hand washed or wiped.

Keurig provides a one year warranty covering defects in materials or workmanship under normal home use.

Bells and Whistles

Auto Off  Automatically powers off 90 seconds after the last brew.

Step-by-Step Indicators  The "Add Water" indicator, a "Brew Handle" indicator, and the Brew button use colored lights to guide you through the brew process.

  • The Add Water indicator flashes blue when there is not enough water in the reservoir.
  • The Brewer Handle Indicator flashes blue once a minimum of 6 ounces has been added to the reservoir. This is to remind you to open the brewer lid and let the water drain into the heating chamber.
  • The Brew button flashes blue when the machine is ready to brew.
  • The Brew button flashes red while water is heating in the lower chamber.
  • The Brew button is a solid red when the coffee is dispensing
control panel

Keurig B31 MINI Plus Color Options

If you are looking for fun colors to spice up your kitchen or desk, the MINI Plus Keurig single cup coffee maker is the Keurig of choice.

Many retailers carry only the most popular Black, Platinum, and possibly Red. But is a good place to look for the more exciting color options.

yellow keurig turquoise MINI Plus purple coffee maker
Yellow Turquoise Aqua Purple
blue B31 flash green white k-cup
Blue Flash Green White
silver colored red coffee maker black
Platinum Red Black

See other 1 cup brewers
View all Keurigs

Product Specifications

Manufacturer Keurig
Model #B31 MINI Plus
Avg Rating 3.9 stars 3.9 out of 5
Number of reviews 527
Price Range between $50 and $100 $50 to $100 USD
Max Brew 10 oz
Programmable N
Auto Off Y 90 seconds
Thermal Carafe N
Pause & Serve N
Filter Type n/a
Warranty 1 year

User Manual

Click image to view or download User Manual
pdf file Owner Guide
B31 MINI Plus
Keurig Brewing System

Pros and Cons - What Real Owners Like and Dislike

Overall like it


bullet The small counter top footprint and low maintenance of this Keurig single cup coffee maker make it ideal for situations that don't justify a larger machine. The MINI Plus is unobtrusive. Consumers really appreciate that this brewer "fills the gap" in situations like these:
  bullet There is a single coffee drinker in the household.
  bullet People who only want a cup now and then.
  bullet Times when you'd just like to enjoy a beverage, but don't really "need" it. A small cup after dinner, for example - nice but not worth the mess of brewing a pot.
  bullet Someone who wakes up before the rest of the household can make a quick cup for themselves before putting on the 12-cup drip machine for the family.
bullet The MINI Plus is a great machine to take with while traveling. The fact that you can drain the heating chamber completely makes this possible. The compact size makes it easy to transport. Many appreciate the superior taste and cleanliness over hotel coffee.
bullet The MINI Plus gets lots of compliments on the consistent good taste of the brewed coffee, more so than the larger Keurig models. Since all Keurigs use the same K-Cups and brew method, it is likely that the MINI Plus achieves a better extraction temperature, and therefore produces a better tasting product.
bullet Consumers like the polished, sleek design of this Keurig single cup coffee maker. The compactness makes this model ideal for many situations: boat, RVs garage, dorm room, travel, cabin, small kitchen, vacation home, master bedroom, desktop, storage in a cabinet rather than counter top.
bullet This brewer's simplicity make it a good fit for users who just don't have a lot of time to pay attention to making coffee. It's great for brewing a cup as you are running out the door. No programming, no worry about turning the power off, no water being kept hot in the tank. And there is virtually no clean up - you can take your cup and go.
bullet Some consumers really like that this machine's reservoir only holds the one serving. They know the water used for brewing is always fresh and clean.


bullet There are many who hate the design element which requires the brewer lid be closed while filling and then opened to drain water into the heating tank. If you don't follow the steps exactly, you can end up with an overflow into the drip tray. The brewer gets very confused and won't brew until you've completely drained it and started the process again. Some consumers understand the process and never have problems, while others are frustrated again and again.
bullet Though this Keurig single cup coffee maker is supposed to accommodate "small" travel mugs, many consumers even have trouble fitting their regular household coffee mugs under the brew funnel. Mugs over 5" tall will be a problem.
bullet Consumers who already own a larger Keurig model frequently expressed some disappointment with quality of materials used in the MINI Plus. In comparison, the MINI Plus seems to be made of cheap, clunky plastic.
bullet The MINI plus seems to be even more finicky than other Keurig models about the water used for brewing.
  bullet Keurig recommends the use of bottled or filtered water.
  bullet Keurig advises against the use of distilled or reverse osmosis water.
  bullet Based on the response from Keurig Customer Service to consumer calls about the MINI Plus's failure to brew, it seems as if even a few brew cycles using tap water can be enough to clog the machine and require descaling.
  bullet Consumers report trouble using any kind of chilled water. It seems refrigerated water does not heat to the proper temperature within the two minute heat cycle allotted by the brewer, so the brewer fails to brew. Later, when it reaches room temperature, the brew cycle will be successful.
bullet As with other Keurig single cup coffee maker models, there are reports of brewer malfunction, often within the first week of use. With the MINI Plus, the reports do not point to a widespread design issue. Reports indicate that user error may be the source of many "malfunctions".
bullet K-Cups are not recyclable at this time.

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