How Does a Bunn Coffee Maker Work: We’d Like to Help You Understand

BUNN BX Speed Brew Classic 10-Cup Coffee Brewer, Black If you’re buying a Bunn, you should know that Bunn-O-Matic, the company behind it, invented pour-over drip coffee makers. It was the founder of the company, George R. Bunn, Jr. who invented them, and he is the one who invented the flat-bottom fluted coffee filter as well. As you know, both of these inventions are still being used today, and they have largely contributed to coffee-making.

Many people are still mildly confused about how to operate their Bunn and we don’t blame them. Pour-over drip coffee brewers do seem a bit tricky to operate mostly because they operate differently from, let’s say, automated coffee machines. However, it’s not hard to learn the ways of a Bunn and we can simplify the learning process for you.

Briefly about Bunn coffee makers

There are different Bunn coffee makers, but there’s no difference in the way they brew the coffee. A Bunn coffee maker is made to brew a carafe of about 10 cups with a unique brewing mechanism.

A Bunn coffee maker’s design is inseparable from the brewer’s brewing mechanism.  In general, these coffee makers have a large reservoir in the back and a brewer funnel in the front. The front base of the coffee maker is a carafe warmer; the carafe sits here while and after a brew session. When brewed, the coffee is sprayed with hot water—a process helped by the showerhead of a Bunn.

When you purchase a Bunn, you get it as preset. The coffee maker doesn’t ‘travel’ to you alone, however; you do get a glass or a thermal carafe with it as well.

Get your Bunn ready for brewing

Before you can actually brew coffee, you need to put your Bunn into ‘power mode.’ You also need a proper first setup for the coffee maker so that a nice stream of coffee fills your carafe.

It is important to remember that you should NOT plug in the Bunn before you do the setup. Plugging it in before it’s set could permanently damage it and leave you ‘Bunnless.’ All jokes aside though, don’t plug in the brewer while you’re setting it up for the first time.

But, what’s a first-time setup?

Well, for Bunn coffee makers, a first time setup means filling their water reservoirs with nothing but water.

That’s just the simple, general idea behind the setup, though; the detailed explanation of the setup might confuse you. Because of that, in the following lines we’ll be extra careful when explaining to you how to perform the first setup of your Bunn. Trust us, it’s easy to do it.

BUNN BT Velocity Brew 10-Cup Thermal Carafe Home Coffee Brewer, Black The setup

In order for the coffee maker to properly work, its reservoir has to always be filled with water because, if the water heating switch is on, the brewer’s heaters start heating the water as soon as you press the ON/OFF button of the coffee maker.

The water heating switch is placed on the right bottom side of the brewer. When you do the initial setup, you should NOT have this switch on because you will damage your brewer. The initial setup is done with this switch turned off.

If the switch is turned off, the first step is to make sure that the brew funnel is set in place. Don’t put a paper filter inside the funnel during this step of the process.

Once the brew funnel is in place, fill the Bunn carafe with filtered water to the top and open the lid of the brewer.

When you open the lid, you’ll notice a white lever-like thingy underneath it. After you pour the water from the carafe into the brewer and close the lid, the white lever will be pushed down and the water will flow into the water tank; it’s actually the lid that pushes the lever down, which is why you need to close it once you’ve poured the water into the brewer.

Before you close the lid, however, place the empty carafe on the warmer. That way, the carafe will collect the water in case the brewer starts dispensing it! Water will probably not be dispensed in this stage of the process, but it’s wise to be precautions.

The water will take about three minutes to flow into the tank. After that, you’ll need to repeat the process once again to completely fill the coffee maker’s reservoir.

When will you be able to brew some coffee?

After you’ve poured one more carafe of water into the Bunn, you should put the carafe underneath the brew funnel once again. It usually takes two carafes of water to fill a Bunn’s water reservoir, so you should expect that water will flow through the brewer this time.

Always put the carafe underneath the funnel before you close the lid to avoid a mess caused by water.

The water that will flow through the brewer will be cold because the switch for heating the water has been off throughout the setup. Since Bunn coffee makers need to have cold water poured in them when they are about to brew, you can use this water to brew the coffee.

Once the water starts coming out of the brewer and into the carafe, you’ll know that its water reservoir is full. Wait until the Bunn stops dispensing water and then brew your coffee.

Brewing coffee with a Bunn coffee brewer

Once your Bunn brewer is ready to brew, you can turn the heating switch on. It will take the brewer’s heater about 15 minutes to heat the water inside the tank.

After 15 minutes, take your favorite coffee and put it in a suitable paper filter. Use more or less coffee depending on your preferences. Then, put the filter with the coffee into the brew funnel and place the funnel into the funnel guide if it’s not there already.

If your Bunn brewer has a warmer switch, turn it on. This switch has nothing to do with the brewing process, but it will warm up the warming plate and keep the coffee in the carafe hot.

It is important to remember to turn the warmer off when the carafe is empty or almost empty. If you don’t do this, the heat can damage your carafe, and no one likes a cracked carafe.

The last thing you’ll need to do before you brew your coffee is fill the carafe with cold filtered water. Open or slide the brewer’s lid to the side and pour the water into it. Then, put the carafe underneath the brew funnel and close the lid. You should have a full carafe of coffee ready in a few minutes.

BUNN CSB3T Speed Brew Platinum Thermal Coffee Maker So, how does a Bunn coffee maker work?

Bunn coffee makers operate in a simple way. After you pour a carafe of cold filtered water into the brewer and close its lid, the brewer pushes the water to the bottom of the tank through a special pipe. Because the residual water inside the water tank is hot, the cold water pushes it upwards. The hot water then goes inside an inlet tube and, from there, it goes to the brewer’s showerhead, falls onto the coffee, and brews it.

Taking care of your Bunn coffee maker

Now that you know how to brew coffee on your Bunn brewer, let’s talk about how to clean and maintain it.

Bunn coffee makers don’t need to be descaled, and that gives them some advantage in comparison to other coffee makers like Keurig, for example. However, you will need to rinse the brew funnel and the carafe and wash them if there’s coffee residue that needs to be removed.

You should also rinse and unclog the showerhead from time to time and wipe your coffee maker when you notice stains and occasionally delime the inlet tube of your brewer with the deliming probe shipped in the box.

To delime the brewer, unscrew the showerhead, put the deliming probe inside its opening, and slide it in and out. Any coffee residue inside the pipe should fall out in no time.

Wrapping up with some useful tips

  • Don’t let the coffee sit on the warmer plate longer than 20 or 30 minutes because its flavor will change.
  • Clean the carafe, its lid, and the brew basket with soap water or with a special product for coffee residue removal.
  • Bunn coffee makers have a file basin that can hold more than 50 ounces of water, so don’t be scared of it overflowing.
  • These coffee makers use filters number 4.
  • You can turn the switch for heating the water off if you want to save energy.
  • A Bunn coffee maker can brew you a 5-ounce cup of coffee.
  • One tablespoon of coffee should be enough for one cup of coffee.


Related articles

Does the Ninja coffee bar make espresso?

Bonavita 1800 vs 1900

Coffee makers not made in China

7 thoughts on “How Does a Bunn Coffee Maker Work: We’d Like to Help You Understand”

    • Once the brewer is filled and heated, you then control the quantity of coffee made by the amount of water poured in when making coffee. You have to completely fill it to begin. After that, you get out what you put in. (There’s a lower limit, depending on the model, IIRC the home units are now all four (5 oz.) cups.

  1. The initial fill takes at least two full carafes; I use three, just to be sure. Excess will be captured in the carafe as the third is “loaded” when the door is closed and can be discarded.


Leave a Comment