Undoubtedly one of the most exciting coffee-making innovations in recent years has been the invention of the Keurig. What started out as a work-place-only solution to stale pots of coffee has evolved into one of the most successful coffee makers for in-home use to date. Even if they don’t own a Keurig themselves, nearly every coffee drinker today knows what one is. But even those who do own one probably can’t answer the question “How does a Keurig work?”
There’s some kind of magic that transforms the coffee inside that tiny K-Cup into a fresh, hot, delicious mug of coffee. It’s the kind of magic made of sensors, circuit boards, and silicone tubing. Today’s Keurig is definitely not your grandparent’s Mr. Coffee! We’re going to take a closer look at this sophisticated coffee-brewing system that makes brewing a single cup of coffee the simplest it’s ever been.
A Brief History of the Keurig
According to Wikipedia, John Sylvan is the mastermind behind the Keurig coffee maker design. His goal was to solve the age-old problem of workplace coffee turning stale and bitter while sitting on a warming plate all day. Sylvan first envisioned the individual coffee pods that would create one fresh cup of coffee at a time. Then he created the Keurig coffee machine as the method for brewing those single-use pods.
The Keurig company was founded by Sylvan along with his former college roommate, Peter Dragone, in 1992. In an amusing side note, Sylvan’s explanation for the company name is that he looked up the word “excellence” in Dutch. If you use Google Translator, however, you’ll find the top Dutch-to-English translations for keurig are neat, elegant, and exquisite. If you reverse the process and search the English-to-Dutch translation of “excellence,” you get “uitmuntendheid.” Even if the definition is a little off, Keurig was definitely the better choice for the company name than Uitmuntendheid!
A Workplace Solution
The first Keurig coffee makers were not released until 1998 and were made exclusively for office use. These over-sized commercial units were literally “piped in” to a water building’s water line, so, upon being hooked up, they could not be moved.
Once installed, however, these early Keurigs revolutionized the office coffee experience.
With the advent of the Keurig system, gone were the stale pots of coffee of mediocre quality. There were no more burners left on all day scalding the coffee, ruining empty pots, or creating a fire hazard. With a variety of K-Cups on hand, every employee could now brew their own fresh cup of coffee just they way they liked it right when they wanted it.
Talk about a great company (ahem) perk!
Keurig at Home
Of course the employees who were partaking in “the Keurig coffee experience” during the work week began clamoring for the same indulgence on the weekends. It would take another six years, however, for the technology of the commercial Keurig to be redesigned into a model both compact enough and affordable enough for home use.
By the time Keurig was ready to release their first home brewer in 2004, they discovered many of their competitors were, as well.
In an assertive marketing move, Keurig sent representatives into retail outlets to perform live demonstrations of their in-home machine and give out free samples of the coffee it brewed. This hands-on marketing strategy coupled with growing familiarity of the Keurig name through the thousands of workplace brewing systems that had been installed helped ensure Keurig’s quick domination of the single-serve coffee market.
Today, Keurig is a multi-billion dollar, multi-faceted corporation that has expanded its single-serve pod concept to include not only coffee but also tea, hot chocolate, a variety of specialty beverages, and even soup.
The K-Cup Design
As noted, Sylvan’s need to create a single-serve coffee brewing machine evolved out of his initial idea for an individual-use coffee pod. What’s now known as the K-Cup took years of trial and error to perfect. And there’s more to those little cups than meets the eye.
Each K-Cup consists of a small plastic container that’s fitted inside with a small paper filter. Coffee grounds are placed in the K-Cup’s paper filter. This is similar in concept to the basket and filter design found in a standard electric drip coffee maker.
The coffee and filter are sealed into the K-Cup using an aluminum foil lid. During the sealing process, the K-Cup is flushed with nitrogen gas to force out any oxygen in the cup. This prevents the grounds from oxidizing and going stale. The result is coffee that is perfectly portioned, compactly packaged, and hermetically sealed. Since K-Cup coffee is protected from oxygen, moisture, and light until the time it is used, it has a long and stable shelf life.
From K-Cup to Coffee Cup: The Basic Keurig Brewing Process
Making coffee with a Keurig machine is as simple as filling a reservoir with water, pressing the power button, and lifting the lid to drop in a K-Cup. Once the Keurig has heated the water and detects a properly-inserted K-Cup, it takes just one more press of a button to select the desired ounces of coffee to be brewed. Within a minute, fresh, hot coffee has been dispensed from the Keurig into the coffee mug, and the process is complete.
A Keurig truly is ridiculously simple to operate. It provides a fast, fuss-free, mess-free cup of hot, fresh coffee over and over again. No doubt this ease of use is a huge part of the Keurig’s appeal. Everything on the outside is elegant, sleek, and simple.
On the inside, however, the Keurig is a whole different machine. It’s a complex tangle of tubes and wires operating a heating element, pump, and circuit boards. The complexity of design behind our “simple” mug of K-Cup coffee is almost mind-boggling.
So let’s take a closer look at the inner workings of the Keurig. It’s quite fascinating!
Water for Coffee
Besides the coffee grounds inside the K-Cup, water is the other essential element necessary for brewing a cup of coffee with the Keurig. Although the size and exact configuration varies by model, every in-home Keurig has an easily-accessible reservoir for holding the water that will become the coffee. The water reservoir on a Keurig is more than just a container, however. It has some unique features and functions that are integral to the safe and efficient operation of the machine.
To help protect the inner components and prolong the life of the Keurig, the water reservoir contains a removable, changeable filtering system. The base component contains a fine mesh screen that will keep sediment from passing through the water into the Keurig. A charcoal-activated filter sits on top of this base and is locked in place by a casing with a long handle that simplifies the removing/replacing process. The numbers on the dial at the top of the handle represent each month of the year and can be turned to remind the owner in what month the filter will need to be changed again.
The replaceable charcoal filter helps remove chemicals and contaminants from the water in the reservoir. This is good for the Keurig in that is helps prevent calcium build-up on the inner components and tubing. It’s also good for the coffee drinker since charcoal filtration helps reduce the taste and odor of any chlorine in the water, thereby improving the taste of the coffee that’s brewed.
Water Level Sensor
The Keurig water reservoir contains an enclosed “pocket” that rests against the machine when the water container is properly set in place. Inside this sealed plastic pocket is a magnetized disc that floats when water is added to the reservoir. This magnetic disc interacts with a sensor that’s inside the Keurig’s casing to ensure there is enough water to fill the heating unit so that it doesn’t burn out and/or become a fire hazard.
As long as there is ample water to keep the disc afloat, the Keurig functions normally from power-up through brewing. When the water level in the reservoir drops, however, so does the disc. And when the sensor inside the Keurig no longer has contact with the magnetic disc, the heating element is switched off, the “Add Water” LED indicator light turns on, and the Keurig will not function properly until water is added to the reservoir.
Pumping and Heating
When a Keurig is powered on, water is drawn from the exterior container into the Keurig’s heating element so the brewing process can begin. There is a small pump located alongside the water filtering system on the inside of the Keurig casing that handles this task. The pump accesses the water through an inlet in the permanently-attached base where the reservoir sits.
The pump carries the water through the Keurig via heat-resistant silicone tubes and empties it into the heating chamber.
There are sensors of different heights within this sophisticated component that ensure the water is heated consistently with each use regardless of varying water levels.
As a safety feature, the water level indicator discussed in the section above will interrupt power to the heating element unless there is adequate water available to fill the chamber. Without this feature, it would be easy to burn out the heating coils and damage the entire Keurig, rendering it unusable. A red indicator light along the top of the Keurig alerts the user when more water is needed to continue and complete the brewing cycle.
Needles in the K-Cup
Once the filtered water has been pumped into the Keurig and heated, it is time to brew a cup of coffee. As we learned, the ground coffee used in a Keurig is pre-measured and tightly sealed within individual plastic pods called K-Cups. How exactly does a Keurig access the coffee inside the K-Cup? Through the strategic placement of very sharp needles.
To insert a K-Cup into the Keurig for brewing, one lifts the large handle at the top of the machine. This reveals the round holder where the still-sealed K-Cup is placed. It also reveals multiple warnings about the sharp objects — the needles — found in this area.
One needle is located above the K-Cup in the “lid” area of the Keurig that rises when the handle is lifted. The other needle is located in the bottom of the receptacle that holds the K-Cup. When a K-Cup is dropped into place in the Keurig and the handle is depressed to close the brewer, an audible “pop” can be heard as the needles pierce the foil on the top of the K-Cup and the plastic cup itself on the bottom.
From K-Cup to Coffee Cup
Once the lid of the Keurig is closed, pressure sensors cause blue LED lights to flash. This prompts the user to select the volume of water to be dispensed. Once a choice is made and the corresponding button pushed, the Keurig gets to work, pumping the heated water out of the heating chamber and up to the K-Cup holder.
Once water reaches the K-Cup, it is forced through the hole that has been punctured in the foil top of the K-Cup. Hot water floods the empty chamber of the cup. It surrounds and saturates the coffee grounds, transforming the plain water into brewed coffee. The coffee, of course, flows out of the K-Cup through the hole that was punctured in the bottom.
It is important to note that the hole on the top of the K-Cup where the water enters is larger than the hole in the bottom where the brewed coffee drains into your waiting mug. This allows the water to enter the K-Cup faster than it is dispensed. This ensures the water remains in contact with the coffee grounds long enough to produce a flavorful cup of coffee.
The Brains Behind the Brewing
Anyone who has used a Keurig know it is one of the simplest ways to make a cup of coffee. You put water in the reservoir, turn on the machine, pop in a K-Cup, select the size coffee you want, and that’s it, the Keurig does the rest. There’s no need to measure the water, hassle with paper filters, or scoop out messy coffee grounds.
As is typical with technology, however, the easier something is to use on the outside, the more complex it tends to be on the inside. The Keurig is no exception. So far we’ve looked at the water filtering and sensoring system and mentioned pumps, silicone tubing, heating chamber, pressure sensors, and LED indicators, all of which only scratch the surface of the Keurig’s hi-tech complexity.
With all the fancy features and functions, is it any surprise that a Keurig is also part computer? The true brains behind the brewing are the various printed circuit boards (PCBs) found within the machine.
I have to stop and confess right here that I am nowhere near tech-savvy enough to explain the components and functions of these boards in detail. Nor do I know what each is properly called. Still, we’ll take a brief look at them below, Those who understand these things can enjoy a good chuckle at my attempts to make sense of these complex parts in a few sentences. The accompanying photos, despite their poor quality (which will be explained in the next section), should provide added insight for those who understand what they’re looking at and inspire some mind-boggling awe for those, like me, who don’t!
Power Supply Board
Located at the base of the Keurig, interior to where the power cord runs into the machine, is a small power supply circuit board. This basic electrical component “filters” the flow of electrical current into the brewer. In addition to facilitating the proper electrical input, this board also contains safety features that help protect the Keurig against high-voltage spikes that could damage internal components or spark a fire.
Internal Circuit Board
The largest PCB in the Keurig sits vertically along the right interior of the unit. This board is responsible for the internal functions of the Keurig. Its components regulate the electrical flow within the machine so that the pumps and heating element operate safely and efficiently.
Upper Circuit Board
Another large PCB is situated horizontally just below the top operational control panel of the Keurig. This is the board that allows us to give direction to unit. It contains the power on-off button, the coffee-size selector buttons, the LED indicator lights, and the auto-off control.
About Those Blurry Images…
We own a Keurig, but only one. The external pictures I’ve used for this article are mine, but I wasn’t willing to pull our Keurig apart for illustrative purposes because I knew I’d never get it back together! So, to offer you a visual peek at the crazy insides of the Keurig, I nabbed screen shots from this YouTube video by electronicsNmore:
If you’re at all interested in a closer look at the complex inner workings of your Keurig — and how to test the Keurig’s various components for proper functioning — I highly recommend you check out this fascinating video by someone who clearly understands the technical workings far better than I.
Even though we’ve owned and operated one for a few years now, I never gave much thought to how a Keurig works. Researching this article was quite an eye-opener. Now we know that the simple process of making coffee with a Keurig is, in reality, anything but!
If you’re considering a Keurig — or are ready to upgrade — but are confused by all the different models available, check out our helpful Keurig comparison guide. We break down all the options and note the pros and cons of each model so you can choose the best Keurig for your needs.
What do you think of how much this “simple” coffee maker has going on inside it? Let me know (or just say Hello!) in the comment section below.