Cleaning a Bunn coffee maker involves more than just keeping the outside of the machine looking spotless. The water tank and spray head tube are both susceptible to a buildup of mineral deposits, which can potentially slow the brewing process to a mere trickle. Fortunately, Bunn coffee makers come with a special tool that will allow you to easily remove any deposits in the spray head. All you need to clean the water tank is plenty of white vinegar, and dish soap is sufficient for cleaning the outside of the coffee maker.
Using the Bunn Deliming Tool
Be sure the coffee maker has been off for at least two hours to avoid burning yourself and unplug the machine to eliminate the risk of electric shock as well. Next, find the deliming tool that came with your machine. Different Bunn coffee maker models have different tools, so yours may be either metal or plastic. If you cannot find your Bunn deliming tool, a long and thin zip tie will suffice.
Remove the carafe and the brew funnel from the machine. Unscrew the spray head, which is a dome-shaped piece of plastic sitting directly above the brew funnel. This will expose the spray head tube, which transports water from the water tank. Insert the Bunn deliming tool into this tube until about 2 inches of the tool remains exposed.
Slide and rotate the deliming tool to break up any mineral deposits (also called lime deposits or limescale). Examine the spray head for evidence of these whitish deposits and remove them with the tip of the deliming tool or with a toothpick. Wait to screw the spray head back on until after you've flushed the water tank.
Flushing and Cleaning Water Tank
Now that you've broken up any mineral deposits from within the spray head tube, it's time to run the coffee maker and flush them out. Place the brew funnel and carafe back onto the machine. Add a white vinegar and water solution (Parts Town recommends one part vinegar to two parts water) to the water tank and allow the brew cycle to run completely. The vinegar will help to lift any mineral deposits from the water tank.
When the cycle is complete, discard the water in the carafe. Fill the water tank again and run another cycle to flush out the vinegar solution. You'll need to run several cycles with fresh water until the vinegar smell disappears. You should also notice that the water in the carafe becomes much cleaner after the first couple of the brew cycles.
Once you're satisfied with how clean the water is, wait for the machine to cool down and then reattach the spray head.
Cleaning the Outside
The brew funnel, carafe and exterior of the Bunn coffee maker can all be cleaned with dishwashing liquid. The carafe and brew funnel can be placed in the top rack of the dishwasher or hand washed. Wipe down the exterior of the coffee maker with a soapy rag and follow-up with a dry towel.
To clean stains off the burner, make a paste out of baking soda and water. Apply the paste to a completely cool burner and scrub it with a toothbrush. Spray vinegar over the baking soda and allow the mixture to bubble and lift stubborn stains. Scrub again with the toothbrush and then wipe all the baking soda off with a damp paper towel.
Repeat as often as necessary to keep the coffee maker in good condition.