How Does A Coffee Urn Work How An Urn Brews Coffee

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

Last updated on November 4th, 2023 at 15:52

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.

Keep reading as I talk about this topic and give you a better understanding of an urn and how it brews coffee.

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. 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 ounces (180ml).

What Is A Coffee Urn
A Coffee Urn.

Read: 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 (it’s 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 on 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

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.

Frequently Asked Questions About How Does A Coffee Urn Work

How Do You Use A Coffee Urn?

Fill your coffee urn with fresh water until the desired level. Put your central pole in place, paying attention to make sure it is locked in place.

Put your coffee basket into place and measure the amount of coffee that you need to use and switch on your coffee urn.

How Long Does A Coffee Urn Keep Coffee Hot?

A coffee urn is capable of keeping your coffee hot for 2 to 3 hours while still maintaining a good level of quality. After this window the coffee will become stewed and start to taste off.

Can I Make Tea In A Coffee Urn?

Yes, follow the same rules as making coffee with your urn, paying attention to brew time and being careful not to over brew your tea. Remove the brew basket when your tea is brewed to avoid over brewing.

Can You Put Milk In A Coffee Urn?

Yes, a coffee urn can be used to heat a large quantity of milk. 4 to 5 gallons can be heated in only half an hour. This is a neat way of serving hot milk for a latte, tea or hot chocolate.

Can You Put Apple Cider In A Coffee Urn?

Yes, apple cider and all kinds of beverages can be put in your coffee urn. Hot apple cider for cool late autumn barbecue is a very pleasant surprise. Slowly add it to your electric coffee urn before you switch it on.

How Long Does It Take For A Coffee Urn To Work?

The standard brewing time and rule of thumb for calculating how long it takes your coffee urn to brew a cup of coffee is multiple the number of cups that you are making bu 40 seconds.

This means that is you are making 30 cups of coffee 20 mins is how long it should take your urn to complete the brewing process.

How Often Should Coffee Urns Be Cleaned?

You should clean your coffee urn after every use. Urns are used for large events and functions where large batches of coffee are served quickly. Clean it to ensure that perfect coffee is served at your next function.

Do Coffee Urns Need Filters?

It is not neccessary that you use use a paper filter for your coffee urn as the coffee basked is designed with a built in filter. If you really want to, you can use a filter. Just make sure that it fits the coffee backet perfectly. 

Frappé-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.

Join our active online coffee community on Facebook/Meta and share your tasty coffee recipes, creations and super smiley coffee morning selfies.

Derek Marshall, a certified barista by the Specialty Coffee Association possesses over two decades of experience in specialty coffee shops. He holds professional certifications for coffee brewing and barista skills. Derek is also an author with authoritative books covering various coffee topics including specialty coffee, sustainability and coffee, coffee brewing, coffee recipes, coffee cocktails and books focusing on Brazilian coffee, Vietnamese coffee, Indonesian coffee and Malaysian coffee. As a barista for over two decades, Derek Marshall has worked in specialty coffee shops across the United Kingdom, Spain, Thailand, Malaysia, Cambodia, Indonesia, and Vietnam. His expertise extends to the distinct coffee cultures, specialty beverages, and brewing techniques of each nation. Functioning as a coffee consultant, Derek charges US$50 per hour. To learn more about Derek Marshall and Latte Love Brew, visit his About Me Page. For coffee inquiries, contact him at +34-639-410-375 or, mentioning your name and location

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