Why Bunn Coffee Makers Need Regular Cleaning

A Bunn coffee maker accumulates mineral deposits from water, old coffee oils, and sediment inside the tank and brew basket. These deposits slow down brewing, clog the spray head, and make coffee taste stale or bitter. Cleaning a Bunn takes about 30 minutes and requires only items you likely have at home—vinegar, water, and a soft brush.

The good news: Bunn machines are designed to be taken apart and cleaned. Unlike some coffee makers, you can access the internal parts without voiding the warranty. A clean Bunn brews faster, stays hotter, and produces better-tasting coffee.

Key Takeaways

  • Empty the water tank completely and rinse it under running water at least once a month to remove sediment and old coffee residue.
  • Run a vinegar and water solution through the brew cycle monthly to dissolve mineral buildup inside the heating tank and spray head.
  • Remove and soak the spray head, brew basket, and funnel in vinegar solution for 15 to 20 minutes, then scrub gently with a soft brush to clear clogs.
  • Always run two full tanks of plain water through the machine after vinegar cleaning to rinse out all acid before brewing coffee again.
  • If water sprays unevenly or coffee brews slowly, the spray head is likely clogged and needs soaking and brushing.

Cleaning the Water Tank and Exterior

Start by unplugging the machine and letting it cool for 10 minutes. Lift the water tank lid and pour out any remaining water. Slide the tank out of the machine—it sits in a slot and pulls straight toward you.

Rinse the tank under warm running water, rubbing the inside walls with your fingers to loosen sediment. If the tank has visible brown or gray buildup, fill it halfway with equal parts white vinegar and water, let it sit for 15 minutes, then scrub the inside with a soft bottle brush or cloth. Rinse thoroughly with plain water until no vinegar smell remains.

Wipe the exterior and the slot where the tank sits with a damp cloth. Dry everything before sliding the tank back in.

Running a Vinegar Cleaning Cycle

Fill the clean water tank with equal parts white vinegar and water—typically one part vinegar to one part water. Slide the tank back into the machine and plug it in. Place a large empty cup or pitcher under the brew head to catch the liquid.

Press the brew button and let the vinegar solution run through a full cycle. This dissolves mineral deposits inside the heating tank and spray head. Once the cycle finishes, let the machine sit for 15 minutes with the vinegar solution still inside. Then run another cycle to push more solution through.

Empty the cup and repeat until the tank is empty. The machine will smell strongly of vinegar—this is normal and necessary.

Removing and Soaking the Spray Head and Brew Basket

The spray head is the perforated metal piece at the top of the brew funnel. To remove it, lift the brew funnel straight up and out of the machine. The spray head either unscrews or pulls straight out, depending on your Bunn model. Check your user manual if you are unsure—most Bunn models have the spray head twist counterclockwise to remove.

Place the spray head, brew basket, and funnel in a bowl or sink filled with equal parts vinegar and water. Let them soak for 15 to 20 minutes. Use a soft brush—an old toothbrush works well—to gently scrub the spray head's underside and all the small holes. Do not use a wire brush or anything abrasive, as you can damage the spray head.

Rinse all parts thoroughly under running water. Reassemble them in reverse order: spray head back into the funnel, funnel back into the machine.

Rinsing Out All Vinegar Before Brewing

This step is critical. Any vinegar left in the machine will make coffee taste sour. Fill the water tank with plain water and run two full brew cycles, discarding the water each time. On the third cycle, smell the brewed water—if it still smells like vinegar, run another cycle.

Most machines need two cycles to rinse completely, but older machines or those with heavy mineral buildup may need three or four. It is better to run extra water than to brew coffee that tastes like vinegar.

Cleaning the Drip Tray and Faucet

Slide out the drip tray at the bottom of the machine. Empty any standing water and rinse it under warm water. If there is buildup or staining, soak it in vinegar solution for 10 minutes, then scrub with a soft brush and rinse.

Wipe the faucet (the spout where coffee comes out) with a damp cloth. If coffee has dried around the opening, soak a cloth in vinegar solution and hold it against the faucet for a few minutes, then wipe clean. Dry the tray and faucet before sliding the tray back in.

How Often to Clean Your Bunn

Run a full vinegar cleaning cycle once a month if you use your Bunn daily. If you use it a few times a week, clean it every six to eight weeks. Always rinse and refill the water tank at least once a week, even if you skip the vinegar cycle.

If you live in an area with hard water (water that leaves white or chalky deposits), clean monthly or even every two weeks. Hard water speeds up mineral buildup. If you notice that water brews slowly, sprays unevenly, or coffee tastes off, clean the machine when ready rather than waiting for your scheduled cleaning.

Frequently Asked Questions

Can I use a commercial coffee maker cleaner instead of vinegar?

Yes. Products like Cafiza or Dezcal are made for coffee machines and work faster than vinegar. Follow the product instructions for dilution and soak time. Always rinse with at least two full tanks of plain water afterward, as these cleaners are stronger than vinegar and leave a residue if not fully rinsed.

What if the spray head is still clogged after soaking?

Soak it longer—up to 30 minutes—in vinegar solution. If holes are still blocked, use a thin wooden toothpick or a paper clip to gently clear each hole. Do not use anything metal or sharp that could enlarge or damage the holes. If the spray head is cracked or damaged, it will need to be replaced.

Why is my Bunn brewing slowly even after cleaning?

Slow brewing usually means mineral buildup is still present inside the heating tank, which you cannot reach by hand. Run the vinegar cycle again, let it sit for 20 minutes instead of 15, and repeat. If it is still slow after two vinegar cycles, the heating element may be heavily scaled and may need professional descaling or replacement.

Is it safe to soak the entire machine in vinegar?

No. Only soak removable parts like the spray head, brew basket, and funnel. The heating tank and electrical components should never be submerged. Vinegar solution can run through the machine during a brew cycle, but the machine itself should never sit in liquid.

Can I use apple cider vinegar or other types of vinegar?

White vinegar works best because it is pure acid with no added sugars or colors. Apple cider vinegar can leave residue and may stain. Avoid balsamic, rice, or malt vinegars. Stick with standard white vinegar from the grocery store.