How Does A Coffee Urn Work How An Urn Brews Coffee

How Does A Coffee Urn Work? How An Urn Brews Coffee

Are you thinking about buying a coffee urn and curiously asking yourself, “how does a coffee urn work?“. If that sounds like you, then stay tuned and read this article.

What Is A Coffee Urn?

In the simplest of descriptions, a coffee urn is a large coffee percolator with a spigot at the bottom to help with the serving of the hot drink.

Usually they are double walled and thermal with the ability to keep the drink inside hot thanks to the heating element. They can be used to make a number of other hot drinks, including tea, hot chocolate and milk to name a few.

A coffee urn is measured in how many cups of coffee it can make, usually measured in quantities of 6 ounce (180ml) cups. It is a coffee brewing device that you see at events and parties.

What Is A Coffee Urn
A coffee urn.

Coffee curiosity: How to make make hot chocolate in a coffee urn

How Does A Coffee Urn Work? The Quick Answer!

A coffee urn works not too different from an electric percolator that you may have at home. The hot water flows from the central rod from the bottom to the top, flowing like a fountain over your coffee grounds that are sitting in a perforated filter basket.

The water then, thanks to gravity, seeps through the grounds, resulting in a well brewed coffee below in the chamber below.

How A Coffee Urn Works – The Coffee Brewing Process

The long answer!

A coffee urn has at the bottom a heating element that at the beginning contains only water. The water rises through the central metal rod that acts as a valve.

The functionality and process is the same as a compressed air lift pump where the air (water in this case) gets pushed up the vertical tube. Due to the water at the bottom being hotter due to being closest to the source of heat and the boiling of the water creating bubbles, it gets pushed up and out of the tube first.

With time and the continuation of this process, the water in the chamber below the coffee basket makes a slow metamorphosis from water to brewed coffee.

Due to the heat source being at the bottom when you make hot milk or hot chocolate you need to keep stirring it as if you don’t the milk at the bottom will become burnt.

The brewing of coffee is achieved, as I stated, by filling the perforated basket at the top with ground coffee of a coarse grind size, similar in size to sea salt.

The coffee urn brews and extracts the coffee oils and compounds thanks to the almost boiling water seeping through the grounds from the central tube / metal rod (really a long valve) on to the coarse grounds and slowly over the period of the brewing time, turning the water chamber into a coffee chamber.

The whole process continues on a perpetual basis, and you must be aware of the boiling brew becoming too strong a brew and taking off a too bitter a taste from the coffee oils.

Once your brew has reached a perfect or ideal taste, simply remove the coffee basket.

Of course, if it is tea that we wish to make we fill the basket with tea leaves.

How Does A Coffee Urn Work
A percolator and coffee urn work in the same way

Must Read: Best way to make coffee in a coffee urn

How Does A Coffee Urn know When To Stop?

As the water/liquid and brew mix, be it coffee, tea, milk or hot chocolate the temperature gets close to boiling. At this point the electric heating element switches off and stops the percolation action and process. At this point your coffee is ready.

At which time the indicator light will go out. If you keep it plugged in the machine will then come back on and keep the resulting coffee hot. An Electric coffee percolator works in the same way.

Why Use A Coffee Urn?

One of the main reasons for using a coffee urn is that it is a large coffee pot and can make a large number of cups of coffee in a single filling with coffee urns coming in up to 200 cups at a time.

Mostly you will see a coffee urn in use at functions, banquets, meetings and events at hotels.

Do coffee Urns Make Good Coffee?


in my experience, you can make great coffee with a coffee urn. Due to using a metal filter basket, all the coffee oils remain in the brew and are not filtered out by any cloth or paper filter.

The quality of the coffee that you brew will depend on the roast that you use and the quality of your coffee beans more than the actual brewing method.

Do Coffee Urns Keep Coffee Hot?


Coffee urns can act as a large thermal carafe and maintain the heat very well due to being well insulated. Also, they have an electric heating element that switches on and off automatically maintaining the coffee inside hot.

Frappe-Ing It All Up – How Does A Coffee Urn Work?

Now that your question “How does a coffee urn work?” has been answered, you know how it works and got about using it to make coffee for a crowd of people. You can use your coffee urn for much more than just making coffee, you can make other hot or cold drinks with it also.

Coffee is love, it's more than love — it's a passion of mine. I've had the luck to have travelled and enjoyed the most exotic of coffee's and unique flavors, brewing methods and techniques of making the perfect coffee from Thai hill tribe coffee to Indonesian volcanic coffee, Malaysian coffee that comes in a tea bag and the array of flavors in Vietnam, from Vanilla to Orange to Coconut to Avocado to even salt coffee and the famous egg coffee. The best part of my coffee adventures is getting to mix with the locals over a nice brew and learning how they make it! I'm cited and referenced on Google Scholar for the topic of coffee.

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