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Most people who are dependent on caffeine have breakfast with an old friend — the coffee maker. Every morning you scoop in the coffee, add some water and flip it on, but have you ever wondered what’s happening inside. How does the water get from the reservoir over to the coffee grounds in the filter basket? How does everything heat up so quickly, and what on earth is that gurgling noise?
In this article, we’ll look inside a typical drip coffee maker so you can understand exactly what’s happening when you make coffee. We’ll also look at the possible problems that might cause your coffee maker to stop working. By the end of this article, you may look at your old friend in a completely new way.
Before we get into that, however, let’s do a quick coffee rundown. Coffee plants are evergreen tropical shrubs and small trees, and they grow best between the Tropic of Cancer and the Tropic of Capricorn (often referred to in the coffee world as the Bean Belt) which makes sense because the plants enjoy lots of rain and gentle temperatures. Coffee beans as we know them are actually the seeds of the fruit of the coffee plant — called coffee cherries — and these popular plants have been cultivated by man for hundreds of years.
The two most commonly grown species of coffee plants are Coffee arabica (Arabica coffee) and coffee canephora (Robusta coffee). For more details about what’s in your morning cup, check out the article How Coffee Works. There are lots of coffee makers on the market that can arguably make a better pot of Joe, but in this article, we’ll be focusing on the trusty drip. If your tastes do run fancier, check out the article How the Clover Coffee Maker Works. On the other hand, if you’re gunning for an insider’s look at your kitchen’s appliance of the year, we’ll crack it open and take a peek at the next page.
How the Coffee Heating Element Works
The heating element in your coffee machine is a very important component. It serves two very important functions in the coffee-making process. It heats up the water before it is sprayed over the coffee grounds and it keeps your coffee warm after it’s made.
The resistive heating element is simply a coiled wire that heats up when it is supplied with electricity. It is usually embedded in plaster so that it will last much longer. The resistive heating element is placed between the metal warming plate that sits beneath your coffee pot and the aluminum water tube.
The aluminum water tube is how the water passes through the heating element. It is connected on either end to the cold-water and hot-water tubes and passes the water along beneath the resistive heating element so that it gets nice and hot.
Between the resistive heat element and the warming plate is a white grease that is used to help distribute the heat throughout the plate to keep your coffee warm. This grease is not easy to clean up, so be careful if you ever come in contact with it!
Controlling the heating element is done first and foremost by the power switch. When you turn the coffee machine on, it begins to supply electricity to the heating element so that it can get hot.
There are also sensors that detect when your coffee machine is getting too hot and respond accordingly. They can shut off the heating element and then turn it back on when it has cooled down. The sensors continue this cycle to keep the heating element at just the right temperature.
The Coffee Making Process
Making coffee with a drip coffee maker is pretty easy from your perspective. All you have to do is fill up the reservoir, scoop in the right amount of coffee, put the pot in place, and wait. While you’re waiting, the coffee machine is working on getting everything ready for you.
Here’s a look at the journey from water to coffee through your machine:
- It all starts in the reservoir. You pour your cold, filtered water in and close it up to let it do its business.
- The water moves through the hole in the bottom of the reservoir into the cold-water tube underneath.
- The cold-water tube passes the water through the one-way valve into the aluminum tube beneath the resistive heating element. The water will move part of the way up the hot-water tube within the machine.
- When you turn the coffee machine on the heating element starts to get hot. After a few minutes, the water contained in the aluminum tube will start to boil.
- The boiling water creates bubbles that are big enough to push the hot water through the hot-water tube all the way up through the coffee machine to the faucet.
- The faucet sprays the hot water so that it can even drip over the coffee grounds.
- The hot water saturates the coffee grounds and carries their flavors with it down into your waiting coffee pot.
The Coffee Making Process
Espresso machines are a fast and easy way to get an intense concentration of caffeine in only a couple of ounces of coffee. Once the water is heated up you will only be waiting for about 30 seconds before your shot is ready to go.
Here’s how you get from water to espresso:
- You fill the reservoir with water and turn the machine on.
- The machine starts to heat the water in the heating chamber and lets you know when it’s at the perfect temperature.
- You take the portafilter out of the machine and fill it with the appropriate amount of finely ground coffee. After tamping it down you lock the portafilter back into the machine.
- With your coffee ready to go, you put a small cup under the spout to catch the espresso when it’s done.
- Turning the machine to the espresso setting will engage the switch within it that tells the machine it’s time to go.
- The pump will activate and begin to pressurize the water inside the heating chamber until it reaches about 220 psi of pressure.
- All of that pressure forces the water out of the heating element through the coffee grounds in the portafilter and out of the spout into your cup.
Fixing a Clogged Coffee Machine
If your coffee machine is not functioning the way it should, then it’s probably clogged. Here are a few simple steps you can take to unclog it so you can enjoy your coffee.
Clean out your coffee machine. You can add a cup of vinegar to a reservoir full of water and run your coffee machine as normal. Once all of the water has gone through the machine discard the rinse water. Run a reservoir full of clean water through your coffee machine a couple of times to get rid of the vinegar completely.
Make sure the drain hole isn’t clogged. The hole at the bottom of the reservoir is how the water gets through the machine. If it’s stopped up you should unclog it using a small wire or toothpick to let the water flow through again.
Check the water spout. Make sure the spout where the coffee comes out is completely clean and not being blocked by anything.
Clean out the valve. You will have to remove the base of the coffee machine to get to the valve. Make sure your coffee machine is unplugged before cleaning the valve with warm water and detergent. This should remove any mineral deposits blocking it.