Empty the water tank and unplug the machine before you start

Turn off your Bunn coffee maker and unplug it from the wall. Let it cool for at least 15 minutes if it has been running. Remove the water tank from the top of the machine — on most Bunn models, it lifts straight out — and empty any water that remains inside.

Wipe the inside of the tank with a clean, damp cloth to remove dust or debris. This step prevents old particles from mixing with your cleaning solution or fresh water later.

Key Takeaways

  • Bunn coffee makers need descaling every 3 to 6 months with a commercial descaling solution or white vinegar to remove mineral buildup that slows brewing.
  • The spray head — the part that distributes water over the grounds — can be removed and rinsed under running water to clear coffee residue.
  • The funnel basket and brew basket come out easily and should be washed with warm soapy water after each use to prevent stale coffee oils from building up.
  • Never soak the heating element or internal tubing; water inside the machine should only flow through the normal brewing cycle.

Descale the internal lines with vinegar or a commercial descaler

Mineral deposits from tap water accumulate inside the heating element and tubing over time, which slows the brew cycle and weakens the flavor. Fill the water tank with a descaling solution. Bunn recommends their own descaling liquid, but white vinegar (one part vinegar to two parts water) works for most models. Check your machine's manual to confirm vinegar is safe for your specific model.

Place an empty carafe under the brew funnel. Turn on the machine and let it run through a full brew cycle without adding coffee grounds — the solution will flow through the heating element and tubing. Discard the liquid in the carafe. Repeat this cycle two or three more times with the same solution to break up stubborn deposits.

After the final cycle, empty the tank completely and refill it with fresh water only. Run two full brew cycles with plain water to rinse out any remaining vinegar or descaler. You should notice the brew cycle speeds up once the lines are clear.

Clean the spray head and remove coffee buildup

The spray head sits at the top of the brew funnel and distributes hot water evenly over the coffee grounds. Over time, dried coffee and mineral deposits can clog the small holes. On most Bunn models, the spray head unscrews or pulls straight out — consult your manual if you are unsure.

Hold the spray head under warm running water and use an old toothbrush or soft brush to gently scrub away any brown residue or mineral crust. If the holes are still blocked, soak the spray head in white vinegar for 30 minutes, then brush again. Rinse thoroughly under clean running water and screw or snap it back into place.

Wash the funnel basket and brew basket after each use

The funnel basket (where you place the paper filter and grounds) and the brew basket (where the brewed coffee collects) should be removed and rinsed with warm soapy water after every brew. Dried coffee oils build up on plastic and can turn bitter or rancid, affecting the taste of future pots.

Dry both baskets with a clean cloth before putting them back. If you notice stubborn brown stains on the plastic, soak the baskets in warm water with a little dish soap for 10 minutes, then scrub with a soft brush. Do not use abrasive scouring pads, which can scratch the plastic.

Wipe down the exterior and carafe regularly

The outside of your Bunn can collect dust and dried coffee splashes. Wipe the exterior with a damp cloth and dry it with a soft towel. Pay attention to the area around the brew funnel, where water and grounds can splash during brewing.

Wash the glass carafe with warm soapy water after each use. If hard water stains or old coffee residue clings to the inside, fill the carafe halfway with white vinegar and let it sit for 30 minutes. Scrub the inside with a bottle brush or cloth, rinse well, and dry. A clean carafe also helps you see when the coffee is fresh.

How often to descale and what to watch for

Descale your Bunn every 3 to 6 months, depending on how hard your tap water is. If you have very hard water (high mineral content), descale every 3 months. If your water is soft, every 6 months is usually enough. You will notice the brew cycle slowing down or the coffee tasting weaker — both are signs that mineral buildup is blocking the heating element.

If your Bunn stops brewing altogether or brews only a small amount before stopping, the heating element may be severely clogged. Run the descaling cycle three to five times in a row, allowing the machine to cool between cycles. If the problem persists after a thorough descaling, the heating element may need professional service.

Frequently Asked Questions

Can I use regular white vinegar to descale my Bunn?

Yes, white vinegar works well for most Bunn models. Mix one part vinegar with two parts water. However, check your machine's manual first — a few older or specialty models recommend against vinegar. If your manual does not mention vinegar, use Bunn's commercial descaling solution instead to avoid damage.

What if water leaks from the bottom of my machine during cleaning?

A small amount of water dripping during the descaling cycle is normal. However, if water pools underneath the machine, turn it off and unplug it when ready. The leak may indicate a cracked internal line or a loose connection. Let the machine dry completely, then try one more brew cycle with plain water. If leaking continues, the machine likely needs repair.

How do I know if my Bunn's heating element is broken?

If the machine is plugged in and turned on but the water never gets hot, or if it brews ice-cold coffee, the heating element has failed. This is not something you can fix yourself — the element is sealed inside the machine. Contact Bunn customer service or a local appliance repair shop for a replacement.

Should I leave water in the tank between uses?

Bunn machines are designed to keep water hot in the tank at all times when plugged in. You can leave water in the tank, but empty and refill it every few days if the machine sits unused. Stale water can develop an off taste. If you will not use the machine for more than a week, empty the tank completely.