The Engineer Guy, Bill Hamack, explains how did the nowadays coffee makers get into our homes and how do they work. First, there were the percolators, the predecessors of the coffee makers and they were not very useful as the coffee had a sour taste, a so-called sludge. It wasn’t until mid 1960s when the Bunn company created big coffee makers that could be used it he restaurants. In 1972 Vincent Marotta designed the home dripped coffee maker and the contacted DeMaggio, world renown baseball player, to promote the product. This way, the coffee maker got into many homes.
How does a coffee maker work? It has almost no moving parts, it has a single heating piece that needs to keep the coffee hot and also to heat the water from the reservoir. It also needs to push water up using a tube and make it drip over the coffee.
To heat the water and push it up to over the coffee, the heating element is like a hollow tube that can get hot. The water from the reservoir gets into the tube, it gets heated and it transforms into a mix of hot water and vapour that will get above the cold water due to the smaller density and this is how the water gets up the tube.
The water won’t flow back because there is a one way valve that lets the water go up, but not down. The valve is actually a ball that gets removed by the flow of water when it gets into the heating tube and that falls back over the reservoir opening if the water wants to go back into the reservoir. Clever trick.