When we get bad flavors in our coffee, we usually first address the usual issues: are the beans freshly roasted? Is our grind size correct? Are we using filtered water?
One culprit you might be missing is the cleanliness of your coffee maker. If you have an automatic brewing machine, you might set it and forget it each evening, and over time that can create off flavors in your coffee.
According to NSF International, half of all homes tested in a study had yeast and mold in their coffee machine water reservoirs—making them dirtier than the average bathroom faucet handle
While most of us have strong enough immune systems to protect us from the germs growing in our funky coffee makers, our immunity won’t protect us from the weak, lukewarm, off-flavored coffee, which can be the result of a dirty water reservoir.
Water also leaves mineral deposits, which can build up and impede coffee brewing and decrease the machine’s ability to reach a hot enough temperature.
Coffee, being a seed, also leaves oils and starches behind in the brew basket that linger long after you toss the filter. As anyone who’s tasted rancid oil knows, these compounds can have aggressively bitter, stale tastes that will transfer into the coffee you brew.
The solution, of course, is to wipe your coffee maker clean every day, and deep clean it once a month. Daily, wash your brew basket and pot well with soap and water, and use a clean towel to wipe the filter head and base area.
Deep cleaning isn’t overly complicated; you'll want to run a descaling cycle to break down the buildup in your machine. This means using a descaling solution, which can either be a commercial product, like Cafiza or Brew-Rite, or a DIY solution made of 1-part white vinegar to 1-part water.
To clean your machine, fill the water reservoir with your solution and run a cycle, empty your coffee pot, run another descaling cycle, empty the pot, and run a cycle of water. Wipe down every nook and cranny of the machine with a clean cloth, and you should have a clean coffee maker.
Don’t let funky coffee buildup ruin your morning cup! Daily upkeep and a little elbow grease can help you maximize the flavor of those beans you’re so excited to taste.