How Often Do I Really Need to Clean My Coffee Maker?
If you’ve browsed any of our coffee coverage, you know that we take our brew pretty seriously. From pour-overs to espresso machines, and from bean roast to brew strength, we have strong opinions about it all. This week, it’s all things coffee at Wirecutter.
Cleaning coffee makers is like flossing. Most people do it a lot less than they care to admit, and they fool themselves into thinking everything is okay. Hot water will eviscerate microorganisms, right? And surely the caffeine, a natural antimicrobial, will knock out any remaining survivors.
Well, NSF International, a public health and safety organization, has news for those folks. In its 2011 swab-down (PDF) of 22 homes, it found that yeast and mold had settled into half of all coffee machine water reservoirs tested, making them the fifth germiest item in kitchens and bathrooms—less than the pet bowl but more than (yikes) the bathroom faucet handle. In addition, water leaves mineral deposits inside the machine over time, said Jaime Levy, senior product manager on OXO’s coffee and tea team. This buildup can slow brewing and heating. Worse, noted Paul Dawson, PhD, food scientist and co-author of Did You Just Eat That?, germs can grow there too.
Luckily, most people have healthy immune systems, so a dirty machine won’t kill someone. It will, however, serve up a pot of weak, off-tasting, tepid coffee—and take a longer-than-usual time to brew. Given that this can feel like a fate worse than death on some mornings, properly cleaning your coffee maker every day, with a full descaling every month, is worth your time.
What to do immediately after the coffee brews: Throw out the grounds and the dirty filter from the brew basket, and wipe down any coffee residue in and around the basket and elsewhere on the machine with a clean, damp towel. Wipe dry the water reservoir and let it air dry with the latch open.
What to do by the end of the day: Hand wash all detachable components, inside and out, with hot water, dishwashing liquid, and a clean sponge. This step will loosen any clingy germs as well as coffee oils and residue, which would otherwise mingle with fresh-brewed coffee the next day and give it a stale taste. Get into corners and grooves, where microbes nestle. Rinse well, and then wipe dry and air out. If you’re running the dishwasher, you can instead use that for dishwasher-safe components, such as brewing baskets and glass carafes (but not thermal ones; to be safe, check the manual).
What to do every month: Clean the inside of your machine according to the manual. For some coffee makers, like our top pick (the OXO Brew 9 Cup Coffee Maker), the advice is to run a brew cycle with descaling solution. Our test-kitchen staff uses a DIY method: Fill the water chamber with one part water, one part white vinegar. Place a clean filter in the basket. Run a cycle, empty the pot, and do another vinegar cycle. Replace the filter, empty the pot again, and finish off with tap water. “Extra cycles with just water will clear out the vinegar flavor,” said senior editor Marguerite Preston. Voilà, you’ve vastly upgraded your brew for less than a coffee-bar latte.