Oily Coffee Beans

Coffee bean selection is the heart of a good coffee experience as bean quality can instantly make or break how your coffee will turn out before you even grind the beans and start brewing. Doing your research before buying coffee beans is a great way to start your coffee journey on the right foot.

While there are a lot of things to consider when it comes to choosing coffee beans, a question that we are used to hearing a lot is whether oily coffee beans are good or bad. Since some coffee beans are dry, and some are very oily to the point where the coffee beans are visibly shiny, there is no surprise that the difference between the two is something that is questioned a lot.

As there are a lot of misconceptions about this topic where people automatically consider oily coffee beans to be of low quality, we decided to dive deeper into this topic to explain everything that there is to know about oily coffee beans and hopefully remove any misinformation that you might have heard.

Since coffee beans being oily can mean a multitude of things, we are unable to give you an answer straight away, but we can confidently tell you that coffee beans being oily doesn’t necessarily mean that you shouldn’t use them. 

To begin with, let’s go over how we can really understand whether a coffee bean is oily or not.

How Can You Tell if a Coffee Bean Is Oily?

While all coffee beans contain oils, when we say oily coffee beans, we refer to the coffee beans that contain a visible layer of oil. This phenomenon is a result of coffee oils moving to the surface of the bean and can be caused by a few different factors.

The simplest to tell whether a coffee bean is oily or not is by looking for the layer of oil that coats the coffee bean. Compared to dry coffee beans, you will instantly notice a difference as oily coffee beans have a shiny look that you won’t see on a dry coffee bean.

Another way of understanding whether your coffee beans are oily or not is by simply picking them up with your hand. You’ll notice that oily coffee beans feel different than dry coffee beans. While not all oily coffee beans will leave the oil on your hands, you will easily be able to tell the difference in feeling compared to dry coffee beans.

What Does It Mean When Coffee Beans Are Oily?

Let’s talk about the conclusions we can make about oily coffee beans, as there is no single reason for a coffee bean to be oily.

As soon as coffee beans start being roasted, a process called oxidation starts taking place, where coffee beans start to go into a reaction with oxygen. The oxidation process is faster in higher temperatures, but any temperature that isn’t absolute zero is enough to keep it going.

Oxidation causes coffee beans to degrade over time and lose their chemical integrity, meaning that the aromas and oils of the coffee bean start escaping. While the aromas dissipate to open space, the oils start moving from inside the coffee bean to the surface. 

Since temperature is a primary factor in the rate of oxidation, it’s more common for dark roast coffee to be oily. As the dark roasting process exposes coffee beans to high heat for an extended amount of time, oxidation occurs very quickly and starts pushing the coffee oils to the surface of the bean. Depending on the level of roast, dark roast coffee beans can turn out to be oily right after the brewing process.

On the other hand, coffee beans that are roasted light won’t get oily as quickly as coffee beans that are roasted dark since their exposure to temperature during the roasting process are minimal in comparison. That being said, light roast beans will also oxidize after a certain amount of time that is determined largely by storage conditions, causing them to become oily eventually.

To summarize, coffee beans being oily means that they have been oxidized to a certain level. While this level is achieved rather quickly in the case of dark roast coffee due to longer exposure to heat, it takes a longer time for light roast coffee to get there.

Are Oily Coffee Beans Good or Bad?

Now that we understand why coffee beans become oily, it’s time to decide whether coffee beans being oily is a good sign or not.

Let’s start with dark roasted coffee beans. As dark roast coffee beans can be oily as soon as the roasting process is over, it would be completely wrong to say that oily dark roast coffee beans are not fresh.

While some would consider dark roast coffee beans that become oily right off the bat to be over-roasted as oily coffee beans are technically closer to being spoiled due to being highly oxidated, you will find that it isn’t a problem considering that the coffee beans you are buying are freshly roasted. That being said, it’s a good idea to consume oily coffee beans more quickly as they usually have a shorter shelf life.

On the other hand, in the case of light roast coffee beans, oil moving to the surface of the bean is a sign of the bean losing its freshness. As light roast coffee beans aren’t exposed to high temperatures for a long enough time where they would oxidize to the point to cause oils to surface, the reason behind the surfacing of oils can be tied to the passage of time and possibly improper storage conditions.

Bottom line, it would be wrong to say whether coffee beans are good or bad, solely depending on whether they are oily or not. While using this information can be helpful to a certain extent in determining the freshness of coffee beans, it’s not conclusive.

Will Oily Coffee Beans Clog My Grinder?

Oily coffee beans can indeed cause clogging problems with your grinder, especially if you are using the beans for a super-automatic espresso machine. 

Since there are a lot of reports about the problems that oily coffee beans can cause to the grinder unit of a super-automatic and possibly cause irreversible damage, we recommend not using your oily coffee beans with your super-automatic. While super-automatics should handle most coffee beans unless they are extremely oily, we feel like it’s not worth the risk.

Instead, we recommend using a separate conical burr grinder.

While conical burr grinders aren’t immune to being clogged either, regularly maintaining your grinder will most likely save you from any headache oily coffee beans may cause. By making sure that you clean your grinder after every grind, you’ll minimize the risk of your grinder being clogged. Aside from regular cleaning, it’s also a good idea to pull your grinder apart and give it a deep cleaning now and then, depending on how often you use it.

Even in the worst-case scenario of clogging, it’s rather simple to unclog a conical burr grinder, especially compared to unclogging the grinder unit of a super-automatic espresso machine.

How to Avoid Oily Coffee Beans?

If you’re looking to avoid oily coffee beans altogether, the best way of doing so is to buy a package of light roast or medium roast coffee and consume it as soon as possible.

Since light and medium roast coffee don’t get oily during roasting, you can prevent them from ever getting oily by using them up in the recommended timeframe and with proper storage. 

As proper storage conditions are a key element to keep your coffee beans fresh, ensure that they are kept in an airtight container in a cold and dark place.

FAQ (Frequently Asked Questions)

Can you dry out oily coffee beans?

Unfortunately, it’s not possible to dry oily coffee beans. Since it’s a natural phenomenon for coffee oils to surface, there isn’t anything you can do to get rid of the oil.

Please note that washing the beans will also achieve nothing other than ruining the flavor.

Why do my coffee beans look wet?

A wet look is a characteristic of oils moving to the surface of the coffee bean. 

While this wetness may look like water at first, it’s quite natural for coffee beans to have this look as a result of oxidation.

Should coffee beans be shiny?

It would be wrong to say that coffee beans should be shiny or dry. A coffee bean being shiny simply tells us that the oils of the coffee bean moved to the surface as a result of oxidation.

While this could point to coffee beans not being fresh anymore in the case of light or medium roast coffee, it’s a natural thing to happen in the case of dark roast coffee.


As we have seen, coffee beans being oily can mean numerous things, and it’s not a decisive criterion when it comes to considering whether a coffee bean is fresh or not. While light roast coffee being oily can indeed point us in the right direction of deciding whether it’s fresh or not, it’s not as simple as saying oily coffee means bad coffee.

That being said, the fact that they cause problems to coffee grinders could be a valid reason to avoid oily coffee beans for those who aren’t big fans of dark roast coffee anyway.

Have a great day, and enjoy your coffee!