So you're already on board with the idea that your grinder is critical to making good coffee at home. But...do you maintain it? Crusty, crispy, bean-crumb-filled, coffee-oil soaked grinders can suck the joy out of your brew. A little diligence and regular care will keep things up to snuff—the first step is admitting you have a problem.
Coffee brewers aren't the only things in your life that get covered in...well...coffee. Oily residue from coffee beans (the darker-roasted the oiler and slimier) and fractured debris from flying beans can get lodged, or coat coffee oils or particulate matter in all kinds of places on your grinder.
For the purposes of today's class, we'll assume you're using a burr grinder, which allows your beans to be ground into even particle sizes, rather than a whirlybird-blade grinder (which you should just wipe out carefully with a wet paper towel, then take to Goodwill and go buy a real grinder.) We'll also assume you're not grinding flavored coffee beans through your equipment, which will leave a more lasting odor and residue that will impart its specially engineered flavoring into subsequent cups. Okay, got your toothbrushes handy? Here we go.
1. Get the Grit Out
Breaking coffee into tiny particles creates, guess what, lots of tiny particles. These will coat the insides of your hopper (where the beans are stored before grinding) and the edges of your grinder's burrs, as well as find their way into all kinds of other nooks and crannies you weren't intending to send them.
Barista and grinder engineer Philip Search of Dallis Bros. Coffee favors starting any serious grinder clean-out with air. Remove the hopper and begin with a good vacuuming with any vacuum with a wand extension, or alternately, force air into the spaces by using a can of compressed air. Check the chute your grinds dispense from, as well—if it's clogged or coated with coffee, you can rustle it loose with a finger or toothbrush, then use air to dislodge anything remaining.
2. Keep it Ungreasy
Since the plastic surfaces of grinders can retain oils and coffee schmutz, remove the bean hopper (once there are no beans in it, of course) and wipe down the inside walls thoroughly. If your grinder has a removable grinds chamber, like most Baratza or Cuisinart models for the home, rinse and wipe that down too, especially those tough corners that love to attract miniature piles of coffee. Michael Elvin of Espresso Parts recommends wiping down the inside of the hopper "with a clean dry cloth, removing oils that will build up and become sticky and rancid." Rancid! Where is that dishrag...stat!
3. Clean Dem Burrs
There are many ways to approach burr upkeep and you will find a lot of disagreement out there about it. Some will suggest cleaning burrs with rice, grinder-cleaning pellets, or even quick oats, but experts tend to agree that over time, this simply causes more dust and trouble than taking the burrs apart to begin with. "Running rice through some smaller home grinders can bind the burrs," says Elvin. Then you have to open it up and get in there to clean it anyway...may as well start with the opening."
You can remove burr sets from many grinders quite easily by turning the collared outer ring and lifting the outer burrs outwards. Holding up the burr set, you'll easily see the accumulated coffee stuck to the ridges of the inner ring. Scrub away with a toothbrush and, while you've got it out, scrub the inside freely as well. (Removing the inner burr set is possible, but much more complicated, so you may prefer to just work with those burrs in situ.)
Grinder cleaning pellets are convenient solution, but may create more dust in the long term (or create an ongoing dependency on grinder-cleaning pellets). However, says Elvin, they are ideal for emergency situations when you've "accidentally ground some French Vanilla Mint Mocha beans through your grinder" and may not have time for a full cleaning regime.
Finally, the concept of "seasoning" burrs, recommended for commercial-grade grinders or new burr-sets, can easily be achieved in smaller home models by first running through a little extra coffee of whatever new coffee you're switching to.
4. Think Long Term
Even with light-duty, regular home usage, burrs will need changing after a certain amount of use. It's impossible to give a specific estimate that applies to every single home user, but if your grinder has replaceable burrs, like Baratza's, change them out every three to five years. (These should be priced pretty affordably—around $20—and available by contacting the manufacturer.) After dropping $100 to $300 on a quality grinder to begin with, you want to do everything you can to make this a long-term relationship, right?
Once you've conquered these small tasks, regular upkeep of your grinder should be easy with weekly attention to the big trouble spots. Remove hopper and chamber weekly and wash with soap and warm water, and give the burrs a little scrubbing with a toothbrush and paper towel.
Presto! Your coffee tastes less rancid and sticky already.