Vinegar has a strong odor that intensifies when it's heated. The strong smell may be unpleasant and linger in the air and on household surfaces, including in coffee makers, which can make coffee taste or smell like vinegar. Identifying the cause will help prevent the coffee maker from smelling like vinegar.
The most common reasons for a coffee maker to smell like vinegar are cleaning with vinegar, and acidic buildup. Using vinegar to clean a coffee maker will leave a vinegar smell if the coffee maker isn't rinsed thoroughly. Additionally, coffee is acidic, and built-up residue left in the coffee maker will create a smell similar to that of heated vinegar.
Clean the coffee pot and filter basket with mild soap and water, scrubbing off any remaining residue, then rinse several times with hot water. Fill the coffee maker with fresh water, turn it on and allow it to make a pot of hot water. Continue running clean water through the coffee maker until it no longer smells like vinegar.
Run half a pot of white distilled vinegar through the coffee pot once a month to eliminate and prevent residue buildup. Then make a minimum of five pots of hot water in the coffee maker to remove any remaining vinegar.