For the serious coffee drinker, whole bean coffee is the preferred way to buy premium coffee. Grinding coffee beans immediately before brewing results in a more flavorful cup, with a broader spectrum of flavors present than is usually possible with coffee that was preground.
However, due to the natural oils present in coffee, over time, residue will accumulate in all the hidden crevices inside the grinding mechanism. Including the burrs themselves. The results are that your grinder can slow down over time. Also, when old, trapped coffee grounds suddenly release into the batch you just freshly ground, you can get some interesting flavors polluting your coffee. Even worse, if your grinder has been used to grind flavored coffee, those flavors will usually pollute future, non-flavored batches.
Unfortunately, many grinders do not come apart very easily to allow the user to clean them thoroughly to prevent this from happening.
So, what is one to do? Since your coffee grinder's burrs are steel, you don't want to clean them with water or they'll rust. There are aftermarket grinder cleaners out there, but for a quick, easy and cheap solution, clean your grinder with rice. Though, you can clean a blade grinder with rice, usually the grinding surfaces can be reached with a brush or rag. We have displayed the process, from start to finish with a basic burr grinder. Fortunately, this model comes apart so you can see the results of the cleaning.
Start with a Dirty Grinder
Notice the upper and lower burrs are coated with leftover coffee grounds from who knows how long?
Here's a closeup of the dirty lower burrs
Now it's time to clean! Measure out a 1/4 cup of uncooked white rice. Cheap rice is fine. You'd don't need any Uncle Ben's or fancy long-grained rice for this project!
Pour the uncooked rice directly into the hopper just like you would with coffee beans. Set your grinder to a medium grind setting. There are differing opinions on how fine to grind the rice for cleaning. Some prefer to grind the rice very fine, but others have reported damaging their grinder with an ultra-fine setting. We just stick with a medium setting and go coarser with subsequent grinds until the ground rice comes clean.
You'll notice chunks of ground residue and old grounds mixed in with your fresh ground rice. It kind of looks like salt and pepper. It will take two or more 1/4 cup batches of rice to get your grinder clean. But you'll notice each subsequent batch is "whiter" than the first.
When the rice is all "white" you're done. Discard the ground rice in your compost bin, feed the chickens, or ???? (Let us know if you have a better use for them!) At this point, we like to run about a 1/4 cup of medium or lighter roasted coffee through the grinder to release any leftover rice residue. The lighter roasts aren't as "oily" or sticky so they won't sabotage the cleaning you just did.
Now you can clean the rest of the grinder pieces. Your plastic pieces, like the grounds container and lid, can be washed in the dishwasher. Anything metal needs to be cleaned with a brush or compressed air. If you have an air compressor or a can of compressed air you use to clean your keyboard, just blow out any remaining particles left in your grinder. Wipe down the rest of the grinder with a damp cloth or paper towel and reassemble.
Don't the burrs look better?
Here's a closeup of the clean top burr. Not only do they look better, but the rice actually sharpens the burrs, improving the performance of your grinder.
Voila! Now your grinder is clean and ready for that fresh bag of Jamaica Blue Mountain!
Final note: Though we use rice to clean our grinders, and learned this trick from other highly respected coffee industry professionals, not everyone is fond of this method. The biggest argument against it being that rice has it's own sugary oils that can adhere to your burrs. Others claim that some grinder motors have actually locked up when rice was ground. We haven't felt the first argument was noticeable and never experience a seized up motor when grinding rice. But, these are some extra considerations for you. We don't want you upset with us if you find your favorite Guatemalan now tastes like Chicken Lo Mein, or your grinder breaks.
P.S. Don't grind Chicken Lo Mein in your coffee grinder! Only use uncooked white rice! :-)