# how do coffee machines heat water so fast?

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how do coffee machines heat water so fast?

In: Physics

They have a pretty high heating power (thousands of watts) for a small amount of water (compared to something like a shower or central heating of a building).

Drip coffee machines only heat a tiny bit of water at a time, right before it drips out. So all that power goes to just the small drip of water. If you look at how long it takes to heat all the water(i.e. finish brewing), it will be about the same as an electric kettle with the same power heating element and the same quantity of water.

Electricity converted to heat is a 100% efficient process, unlike using fire and a kettle to heat the water.

They don’t. They only have access to 120v of power. It just seem like they heat water fast because they only ever heat a small amount at a time. If you want to get a sense of how powerful they actually are, time how long it takes to run the whole amount of water through the filter as compared to how long it takes to boil an equal amount on your stove.

As others have said most heat a tiny bit at a time

The Bunn brand (and maybe others). Are frequently seen in restaurants, (they also make home units) and actually have a hot water tank, so there’s an entire pot (or more) of hot water ready to go, when you pour the cold water in, it pushes the hot out, then heats the new water for your next pot.

It depends on the machine. Classic drip coffee machines use a “bubble pump” they heat a small amount of water (like a tablespoons worth). The steam bubble rises pushing the warm water ahead of it up and out on the coffee.

Keurig and other single cup coffee makers heat a cups worth of coffee at a time and hold it until you push the button. This is why when you power on a Keurig it takes a minute or two before it lets you use it.

It depends on the coffee machine or the water. Warm water takes around a minute to heat. While you use around a room temp water it takes around 3minutes. The coffee machine depends on its brand also, It can be a fancy one that heats really fast. But there is an element in the coffee machine that heats the water so fast.

Its a bit long for the attention span of a 5 year old, but I cued [this Technology Connections](https://youtu.be/Sp9H0MO-qS8?t=979) video up to the 5 minute part where he takes one apart and shows how it works.