Will Oily Coffee Beans Clog A Coffee Grinder?

Are you wondering, “will oily coffee beans clog a coffee grinder?” and what is the best way to deal with it? Read more to find out.

Why oily coffee is bad for your grinder
Oily coffee beans will clog a coffee grinder, leaving you more hassle to properly clean it

Dark roast coffee is a fan favorite with deeper color, darker flavor, and stronger wake-up call – but have you ever spared a thought that after about 20 cranks or so, nothing else comes out of your grinder anymore?  Well, if you take it apart, be prepared to see the grounds stuck in the burr.

Oily coffee beans will clog a coffee grinder, leaving you more hassle to properly clean it. The grease in the beans leaves residue on all the machine’s parts. If you don’t take it apart after every go – in other words – let the grease build up inside, it will be the worst nightmare at the end of the day.

Read on to learn why oily coffee is bad for your grinder and what you can do about it.

Are Oily Coffee Beans Bad?

Will oily coffee beans clog a coffee grinder?
The excessive amount of oil affects the texture of the bean

Oily coffee beans are bad for the grinder; even a clinker made to tackle oily beans like a burr grinder needs a proper cleaning once in a while, let alone an automatic machine or an espresso machine. When the beans are roasted too long, they’re more prone to leaching oil. This type of bean goes rancid fast, so the coffee quality is spoiled much faster.

To explain its short shelf life, let’s look at the bean structure. The excessive amount of oil affects the texture of the bean, leaving it a weaker structure to maintain the coffee’s flavor profile. So why are oily coffee beans so bad for the grinder?

One of the main happenings I can see during the grinding work is that the beans stick to one another, with the oil acting as glue. And when that glue gets in the way, it slows the feeding into the throat of the grinder. From there, the grinding machine cannot sense the weight of the bean column, causing the final ground product to be inconsistent.

If you have to deal with oily coffee beans frequently, you must give your grinder a proper cleaning. Some people have to take it apart daily or every two weeks. Some people just forget to clean it, or they have no clue if their beans are oily or not; hence, the oils end up staining the hopper and grounds bin and clogging the burrs with oil solids.

How To Tell If The Coffee Beans Are Oily

It’s very easy to set oily beans apart from the non-oily ones. These beans are coated with a glossy sheen.

Over-roasting causes the internal shells to rack. Plus, extreme heat also allows the carbon dioxide to react to oxygen, leaving the surface an extra shiny look.

That being said, oily coffee beans are mostly dark roast. Keep in mind that dark roast and light roast coffee will release a much higher level of oil after several weeks or when the beans are not stored properly.

You might find our explainer on why are some coffee beans oily helpful.

How Do You Grind Oily Beans?

How do you grind oily beans?
A 100 gram serving of coffee beans can give you approximately 300 calories

A burr grinder will make your life a lot easier if you have to deal with oily beans on a daily basis. When you bring home a new burr grinder, make sure to give it some seasoning because the cast burrs are often rough and unfinished. Plus, a burr grinder is easy to clean as it doesn’t require much work to disassemble the machine.

However, some of you may not have a burr grinder at home but an automatic coffee machine instead. Remember that those automatic machines risk malfunctioning over time. If it happens, the best way to deal with it is to get professional help from a service center.

Removing some of the oil before throwing the beans into the hopper will save you time and effort. For a new coffee batch that is not ready for use, keep it in an air-tight container and place it in the dark. Less exposure to the air means less oxidation, and less oxidation means less oil released.

Before grinding, dry the beans with a paper towel or napkin to absorb excess oil. During the grinding, switch the setting to a coarse grind to halt the oil from releasing even more. On top of that, coarse grind size also distributes a rich flavor and chocolate note in the coffee.

How Do You Get Rid Of Oil In Your Coffee Grinder?

Cleaning up the oil inside the machine takes a little more work, but you don’t need expensive equipment. All you need is some plain white rice. Get the cheapest batch you can find from the nearest store, and you’re good to go. 

I suggest a quarter cup of rice in the blade grinder and let it run for a minute until it’s pulverized. Afterward, all the oils and dust will hang onto the rice. Once you dump it all into the bin, you’ll end up with a toned-up grinder for the next use.

Depending on how frequently you grind coffee and how oily the batch can get, you can clean the machine every two weeks or even daily.

You may also need a vacuum to remove the beans from the hopper. If you have an espresso machine at home, you’ll need to employ professional services to clean and tone up the machine. However, the best way is to never use oily beans in the espresso machine.


  • Oanh Nguyen

    Born and raised by a traditional mama-barista, Oanh is a typical Viet coffee aficionado who would spend her entire precious Sunday showing you how to categorize coffee beans just by the looks and smells. She enjoys writing about everything drinks-related while sipping her favorite rosebud tea. Find Oanh on LinkedIn.