How Does a Keurig Work? Understand The K-Cups And Machines

By Shabbir
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Those of us who love our Keurigs probably wouldn’t be able to survive without our single serve fix every morning! But we may be taking these coffee makers for granted: after all, when was the last time you wondered how does a Keurig work?

The way Keurig coffee makers work is actually why they’re loved and hated by either spectrum of the coffee loving community.

Let’s take a closer look.

How does a Keurig work and brew coffee?

Keurig coffee makers use unique pods called K-cups to brew coffee. The K-cups allow these coffee makers to brew just a single serving of coffee every time. This is quite a change from a typical drip coffee maker where you’d need to brew at least 2 to 3 cups in one go.

In fact, Keurig’s exploding popularity probably ushered in the single serve coffee maker era!

Understanding the K-Cup

Before analyzing how Keurig machines work, it’s important to understand how the K-cup works, since the K-cup makes the machine!

Keurig actually did a pretty good job making the K-cups, at least from an engineering perspective. From the outside, the K-cup looks like a simple plastic cup with a lid on it.

However, there’s a lot more to the K-Cup than meets the eye.

On the outside, there is a little plastic cup and a foil lid. Inside, there is a little paper filter basket attached to the top of the cup.

inside of a k cup

Coffee grounds(or indeed, tea leaves or even hot chocolate powder) rest in the paper filter, and there is a little gap between the bottom of the filter and the bottom of the K-Cup.

Before the foil lid is sealed, the manufacturer flushes out the entire cup with nitrogen. Nitrogen is used so that the oxygen is displaced and the only gas now in contact with the coffee grounds is nitrogen.

This is a critical step as nitrogen is an inert gas, and by locking out moisture and oxygen, maximum freshness is retained.

Many K-cup manufacturers use freshly roasted, freshly ground coffee to fill in their K-cups, but this can’t be said for all manufacturers.

Ideally, you’ll get fresher coffee when you get K-cups from smaller roasters rather than big box stores. Even though the grounds are stored correctly, you never know when the beans were roasted unless the manufacturer specifies it!

It’s also useful to note that not all K-Cups are made the same. Depending on the blend you choose, the actual amount of coffee will vary. Typically, most pods have 9 to 12 grams, but some specialty roasters even go all the way up to 18 grams, which would be a very bold 6 ounce cup or a very pleasant 12 ounce cup!

k cup brewing process

How the Keurig brews coffee

Nearly all Keurig coffee makers work in the same way when it comes to the brewing process. Indeed, all Keurigs simply have a button for you to choose the brew size, and that’s about it! The machine will take care of the rest.

The Keurig brewing system has two needles that it utilizes to make your cup.

The needles come into play when you place the K-Cup in the Keurig and close the lid. The first needle is in the lid, and when you close it down on the pod, it pierces the foil lid, opening up a pathway for water to flow through.

The second needle is where the bottom of the K-Cup sits. Here, K-Cups are pierced from the bottom side to provide an outlet for the brewed beverage to flow through. After flowing through the bottom needle, your coffee will hopefully end up in your cup!

Here’s where the magic happens, though.

Inside the Keurig is a water tank and a myriad system of tubes and pipes. Water flows from the water reservoir and into the pipes, where it is taken to a heating chamber to be rapidly heated.

Keurigs will keep a bit of hot water all the time for as long as the machine is on. This is to ensure that you always have a cup of coffee on hand whenever you need one and you don’t have to wait for the machine to generate more hot water before brewing.

From the heating chamber, water flows through the small needle in the top of your K-Cup. Forcing water through the smaller needle pressurizes it. The pressure is not as much as an espresso, but it’s still high enough to properly extract the coffee fast enough,

The hot water flows through the coffee grounds, through the paper filter, and through the needle on the bottom into your cup.

The amount of water that the machine will dispense depends on the brew size that you decide to use.

Since there is no complex brewing here and just a straight, pressurized brew, not only can you make brewed coffee but also hot chocolate and tea.

The pressure and temperature take care of all of the extraction for you.

This really neat video from Wired is a cool stop motion that shows the inner workings of a Keurig machine.

Although this process may seem quite simple, there’s actually quite a bit going on. A little computer inside the Keurig controls everything and ensures everything is working as it is supposed to.

A sensor in the water reservoir lets you and the machine know if there is enough water in the reservoir. If there wasn’t enough water, for example, the heating coils could overheat and burn out as there would be no place for the energy to be transferred to.

The computer also controls the amount of water that goes into the heating chamber and into the brew.

Also read:

Pros of this brewing system

  • By far, the biggest advantage of pod and K-cup brewers is the speed at which it can brew one cup of coffee.
  • By utilizing hot water and pressure, coffee can be extracted very quickly
  • The generic brewing system allows you to make coffee, hot chocolate, and even tea
  • K-Cups are very convenient to use and having a sampler pack lets all household members drink their own preferred coffee
  • The water reservoir is generously sized to accommodate multiple brews before refilling

Cons of this brewing system

  • Pods are much more expensive that coffee grounds
  • Pods generate a lot of garbage
  • Coffee purists don’t consider Keurig to be “real” coffee
  • Keurig machines themselves tend to be expensive

How to use a Keurig

The beauty of the Keurig coffee maker is the simplicity and ease of use. Brewing a cup of coffee is incredibly simple, and whether you see pods as great or diastrous, there is no disagreeing that the Keurig coffee maker brews quick coffee.

To get started, you’ll need to have water in the reservoir, at least enough for your desired cup size(6 ounces or more), depending on how much you’re looking to brew.

Once the machine is powered on, lift up the cover of the pod chamber and place your pod in. Press the lid down firmly to snap it shut. This pierces the cups and gets the K cup ready to brew.

If your Keurig supports it, you can now press the “strong” button to make a stronger brew. Otherwise, just press the button for your desired cup size, and the Keurig will start buzzing and whirring and dispense a cup of coffee in just about a minute.

Next, just open the lid, remove the K-cup, and your machine is ready for the next cup of coffee.

It’s worth noting here that Keurig does offer to recycle K-cups, so you can actually collect the K-cups and send them back to Keurig rather than throwing them away.

A shocking fact about Keurig K-Cups is that the amount of K-cups thrown out every year can go around the whole Earth multiple times!

A short history of the Keurig

Keurigs were invented by a gentleman named John Sylvan. John got the idea from being fed up of drinking (or at least seeing people drink) poor, stale coffee at work.

The problem back then was that there as no way to effective brew a single cup of coffee. Basically, you had to brew a whole lot of coffee at once, and then everyone poured themselves a cup from the pot.

The first people would get a fresh cup, and the later people would get a stale cup.

John developed the single serve Keurig machine, which was initially meant as a commercial brewer for office settings.

Those brewers were plumbed coffee makers that hooked up directly to a water line so the machine would never run out of water!

Eventually, the office version became so popular that demand increased for a home version too! It would take a while, but eventually a home version was released and Keurig has been making one successful brewer after the next.

Keurig did happen to make a slight blunder when they released the Keurig 2.0 system, though! The new system was meant to lock Keurig machines to very specific kinds of pods that had special barcodes.

This meant that any roaster could not just make their own pods without getting licensed from Keurig, and it also meant that many of the very popular reusable K-cups would no longer work.

Keurig received a huge amount of backlash for this and they deprecated the Keurig 2.0 system. The new Keurig brewers all use the original K-cups, which means that they’re compatible with any kind of K-cup.

This has resulted in many smaller roasters such as Bones Coffee and Death Wish Coffee making K-Cups with their signature coffees, too.

Overall, it seems like a smart decision!


The Keurig is a really interesting concept and brought something to the coffee brewing world that was not easily available previously: single cup convenience.

Of course, detractors will say that Keurigs are blasphemy and not real coffee, and many would agree that coffee without freshly roasted, freshly ground beans is not coffee.

However, not everyone has the time to grind and brew every single time, so Keurig wins in the convenience department every single time.

Hopefully this walkthrough of how Keurigs work was useful and entertaining for you!

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About Shabbir

Shab is the Chief Caffeine Officer at Coffee Brewster. When he's not weighing out coffee beans for his next brew, you can find him writing about his passion: coffee.