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Drip Coffee Makers
History
The world’s first drip coffee maker appeared in France more than 120 years ago. Known as the “Biggin”, it was a pot that consisted of two tiers, an upper chamber and a lower chamber.
The upper chamber is a rudimentary brewing chamber, where the coffee grounds are placed. Hot water would be poured into the upper chamber, where it would interact and extract the oils and essences of the grounds, and it would eventually seep through holes in the bottom of the upper chamber and flow into the lower chamber.
The “Biggin” was a fairly simple device, but it paved the foundation for the development of the more advanced and modern coffee makers that we see and use today.
However, the “Biggin” still lacked a key component, which all drip coffee makers use today - the coffee filter.
The First Coffee Filter
In 1908, Melitta Bentz invented the first paper filter. During those days, brewed coffee usually tasted bitter since it was common for the coffee grounds to find its way into the cup.
She thought that if she could find a way to filter out the coffee grounds during the brewing process, coffee wouldn’t be as bitter and it would taste so much better. After testing out different materials for her filter, she finally found that her son’s blotter paper, which he used in school, worked best.
She realized that her paper filter not just prevented the coffee grounds from finding its way into the cup, but also greatly improved the coffee extraction process.
Her paper filter greatly reduced the likelihood of over-extraction; since with it, she could use coffee that was ground into a finer consistency.
Without the “Biggin” and the paper filter, the drip coffee makers of today wouldn’t exist.
Although the modern coffee maker is more automated, it still makes use of the same basic principle of coffee extraction that was introduced by the first drip coffee maker all those years ago. And with the coffee filter, maximum coffee extraction can be achieved consistently.
How It Works
There's a reservoir that holds the water when you pour it into the pot at the start of the coffee-making cycle (on the right in the picture above). At the bottom of the bucket there's a hole, and its role will become obvious in a moment.
There's a white tube that leads up from below the reservoir base, carrying the hot water up to the drip area.
There is a shower head (on the left-hand side of the picture). Water arrives here from the white hot-water tube and is sprayed over the coffee grounds. In some coffee makers, the water comes out of the hose onto a perforated plastic disc called the drip area and simply falls through the holes into the coffee grounds.
The depression on the right-hand side of this figure is the bottom of the bucket. The orange tube on the top picks up the cold water coming down from the hole in the reservoir. The orange tube on the bottom is the hot-water tube (it connects to the white tube that we saw in the previous picture). You can also see the power cord coming in as well.
On the left-hand side of the base of the coffee maker is the heating element. This component is comprised of an aluminum extrusion with two parts: a resistive heating element and a tube for water to flow through. The resistive heating element and the aluminum tube heat the water. On the next page, we'll take a closer gander at what this apparatus looks like.
The resistive heating element is simply a coiled wire, very similar to the filament of a light bulb or the element in an electric toaster that gets hot when you run electricity through it. In a resistive element like this, the coil is embedded in a plaster to make it more rugged. The heating element has two jobs:
When you first put the water in the coffee maker, the heating element heats it.
Once the coffee is made, the heating element keeps the coffee warm.
In the picture above, you can see how the resistive heating element is sandwiched between the warming plate and the aluminum water tube. The resistive heating element presses directly against the underside of the warming plate, and white, heat-conductive grease makes sure the heat transfers efficiently. This grease, by the way, is extremely messy (very hard to get off of your fingers!). You find this grease in all sorts of devices, including stereo amplifiers, power supplies -- pretty much anything that has to dissipate heat.
The coffee maker's switch turns power to the heating element on and off. To keep the heating element from overheating, there are also components such as sensors and fuses. In coffee makers, sensors detect if the coil is getting too hot and cut off the current. Then, when it cools down, they turn the current back on. By cycling on and off like this, they keep the coil at an even temperature. Fuses simply cut the power if they sense too high a temperature. They're there for safety reasons, in the event that the main sensor fails.
Another important part of the coffee maker is the one-way valve. This valve is usually either in the hole in the bucket or in the aluminum heating pipe. If there were no one-way valve, then the boiling water would be just as likely to flow back into the bucket as to rise up the white tube. The one-way valve lets cold water into the aluminum tube, but forces the bubbles of boiling water to flow up the white tube. If you blow on the tube leading into this value, the valve should be open. If you inhale through the tube, the one-way valve should block any air.
I HOPED YOU ENJOYED MY COFFEE MAKER GLOG!!!
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Luicelle 11 months ago
Like your glogs!