Empty the water tank and run hot water through the system first

The fastest way to clean a Bunn is to start with what's already inside it. Turn off the machine and let it cool for a few minutes, then remove the water tank from the top and empty any remaining water into a sink. Fill the tank with fresh water and reattach it.

Turn the machine back on and let it heat up until you hear the gurgling sound that means water is ready. Place a large cup or pitcher under the brew funnel and press the manual brew button (or lift the brew lever if your model has one). Let the hot water run through for about 30 seconds, then stop. This flushes out loose mineral buildup and old coffee residue without chemicals.

Key Takeaways

  • Run plain hot water through the brew cycle once a month to rinse mineral deposits that slow brewing and affect taste.
  • Soak the removable parts—the brew funnel, spray head, and water tank—in hot water with a small amount of white vinegar for 15 to 20 minutes.
  • Use a small brush or pipe cleaner to clear the spray head holes, which clog easily and cause uneven water distribution.
  • Deep clean with a commercial Bunn descaling solution or white vinegar every three to six months, depending on your water hardness.
  • Never submerge the main heating tank or use abrasive scrubbers on any part, as they damage the machine's internal components.

Remove and soak the brew funnel and spray head

The brew funnel (the cone-shaped part that holds the filter) and the spray head (the flat piece with small holes that sits on top) are where most buildup happens. Both come out easily. Lift the brew funnel straight up and set it aside, then unscrew or unclip the spray head depending on your model—check your manual if you're unsure which.

Fill a bowl or sink with hot water and add about one-quarter cup of white vinegar. Drop the funnel and spray head into the bowl and let them soak for 15 to 20 minutes. The vinegar dissolves mineral deposits (calcium and magnesium) that accumulate from tap water. After soaking, scrub the funnel gently with a soft brush or cloth, rinse both parts under running water, and set them on a clean towel to dry.

Clean the spray head holes with a small brush

The spray head has a ring of small holes that distribute hot water evenly over the grounds. These holes clog first and cause water to pool in one spot instead of soaking the entire filter. After the vinegar soak, use a straightened paperclip, a pipe cleaner, or a small bottle brush to gently poke through each hole. You should feel slight resistance as you clear the mineral deposits.

Run water through the spray head under the sink faucet while you work—you'll see water spray out more evenly once the holes are clear. This step takes only a minute or two but makes a real difference in how your coffee tastes. If you skip it, water channels through the clogged holes and leaves dry spots in the filter.

Rinse the water tank and check the intake tube

The water tank sits on top of the machine and feeds water down into the heating tank below. Remove it, empty any water, and rinse it thoroughly under running water. If the tank is cloudy or has white buildup inside, fill it halfway with equal parts white vinegar and water, let it sit for 10 minutes, then scrub the inside with a soft brush and rinse well.

While the tank is off, look at the intake tube—the small plastic tube that runs from the bottom of the tank down into the machine. If you see mineral buildup or discoloration around the opening, soak a small cloth in vinegar and wipe the visible part clean. Do not try to push anything down into the tube itself, as you can damage the internal valve.

Use a descaling solution for deep cleaning every few months

Once a month, the hot water rinse above is enough. But every three to six months (depending on how hard your tap water is), run a full descaling cycle. Bunn sells a descaling solution made for their machines, or you can use white vinegar diluted with water in a 1:1 ratio.

Fill the water tank with the descaling solution, turn on the machine, and let it heat. Run the solution through the brew cycle into a sink or large pitcher until the tank is empty. Let the machine sit for 15 to 20 minutes with the solution inside, then refill the tank with fresh water and run several full cycles of plain water through to rinse out all the vinegar or descaling solution. The smell and taste will be off if you skip this rinsing step.

Wipe down the exterior and check the drip tray

The outside of a Bunn collects dust and dried coffee splatters. Unplug the machine, wait for it to cool, and wipe the exterior with a damp cloth. For stubborn spots, dampen the cloth with a tiny bit of white vinegar. Dry it with a clean towel so water doesn't pool around buttons or seams.

Pull out the drip tray at the bottom (it slides out from the front on most models) and empty any water or buildup. Rinse it under running water and dry it before sliding it back in. If your machine has a removable drip tray cover, wash that separately in warm soapy water and dry it completely.

Know when to call a professional

If water stops flowing through the brew cycle even after you've cleaned the spray head and run descaling solution, the heating tank or internal tubes may be severely clogged. This is not something you can fix at home. Contact Bunn's customer service or a local appliance repair shop—they have tools to flush the internal system without damaging it.

If the machine leaks from the bottom or the water tank connection, or if it no longer heats water properly, those are also signs of internal damage that requires professional repair. Trying to disassemble the machine yourself can void any remaining warranty and may cause injury from hot water or steam inside.

Frequently Asked Questions

How often should I clean my Bunn coffee maker?

Run plain hot water through the brew cycle once a month to rinse out loose buildup. Every three to six months, do a full descaling with vinegar or a commercial descaling solution. The exact timing depends on your water hardness—if you have very hard water, descale every three months instead of six.

Can I use bleach or other cleaners on my Bunn?

No. Use only white vinegar, water, or a Bunn-brand descaling solution. Bleach and other harsh chemicals can damage the internal heating tank and leave residue that affects the taste of your coffee. Vinegar is safe, inexpensive, and works well on mineral deposits.

Why is my coffee brewing slower than it used to?

Mineral buildup in the spray head or heating tank slows the flow of water. Clean the spray head holes with a pipe cleaner and run a descaling cycle with vinegar. If the problem persists after cleaning, the internal heating tank may need professional flushing.

Is it safe to submerge the whole machine in water?

No. Only the removable parts—the brew funnel, spray head, and water tank—should be soaked in water. Never submerge the main body of the machine or the heating tank. Water inside the electrical components can cause damage or create a safety hazard.

What if vinegar smell lingers after cleaning?

Run several full cycles of fresh water through the machine until the smell is gone. Usually three to five cycles is enough. If the smell persists, fill the tank with water, let it sit overnight, then run it through again. The smell will fade completely once the vinegar has fully flushed out.