Should Coffee Beans Be Oily or Dry

When it comes to drinking coffee, opinions differ greatly. While some people may prefer a black, rough-flavoured, caffeine-heavy coffee, others may opt for a more fruity, lighter coffee. However, all coffee drinkers agree on one thing: Their coffee needs to be fresh.

The beans need to be recently roasted and ground for your coffee to be fresh. And while you can have some level of control over that if you ground your beans, you can only hope for a freshly roasted bag of coffee beans. This is where the “dry vs oily beans” debate stems from.

So, should your coffee beans be oily or dry? And which one is fresher?

Both oily and dry coffee beans are relatively standard and both can be freshly roasted. The difference between the two is usually the roast level, which appears in the flavour and the nutritional content.

Coffee beans that appear oily are roasted for more extended periods of time, which leads to a bigger loss of oils leaking from the insides through a weakened shell. This comes with a more intense, but less complex taste.

Dry coffee beans are roasted for shorter periods than oily beans, leading to higher oil levels remaining in the core of the bean. Leading to a more complex, but less intense taste.

There’s a certain wrong view that some people have, where they link dry coffee to being old and stale. At the same time, others link oily coffee with being old and without flavour. We believe that both these opinions are incorrect, as the dryness or oiliness of the beans is more connected to the roast levels than the freshness of the beans.

What Causes Oily Coffee Beans

Oily coffee beans are a result of chemical reactions that occur when the shell of a coffee bean is exposed to oxygen. Dark roasted beans have a more fragile outer shell due to their extended exposure to heat.

This means that the oils within the coffee bean’s core will leak out of the weakened shell, creating the shiny surface that we see on the outside. While this does cause the coffee beans to lose their flavour faster, it can be mitigated by being quickly consumed. Oilier coffee beans have a lower shelf life compared to dry ones.

To understand this further, we need to take a look at the roasting process of coffee beans. The beans start off green. The longer they roast, the more the colour will change. 

Depending on the period of roasting, and the temperature at which they were roasted, the beans start to release oils. A darker roast means more surface oils. This is why overly roasted beans look and feel greasy.

What Does it Mean if Your Coffee Beans Are Oily

It can generally mean two things when your coffee beans are oily, either your coffee beans were heavily roasted until the outer shell was fragile enough to let the oils seep out from within, or the same process happened due to the beans remaining on a shelf or a warehouse for a long time.

Generally speaking, all coffee beans can become oily given enough time. Even if your beans look dry when you first buy them, the oils will eventually leak out due to oxidization. If the roast did not bring out the oils, then your beans are more than a few weeks old.

Oily beans, no matter the cause, mean that the oils that would otherwise be contained within the core are now completely exposed to the oxygen in the air, resulting in duller, less flavoured beans and a shorter shelf-life.

What Does It Mean if The Coffee Beans Are Dry

If you find that your coffee beans are dry, it can be one of two reasons: The beans were not roasted past the 2nd crack, or it has been too long since they were roasted, resulting in the oils completely drying out.

It should not be a bad thing if you find your coffee beans to be dry. You should check the roasting date before determining if your dry coffee beans are old or just lightly roasted. Some people specifically prefer their coffee beans to be light-roasted, as that keeps the coffee less bold, and full of flavour and aroma.

Are Oily Beans Bad For Espresso Machines

Oily coffee beans, which are usually overly roasted, will more than likely cause issues with your espresso machine with prolonged use. All that residual oil that is present on the surface of these over-roasted beans will start to cling to the machine components, and over time, they will make the cleaning process harder.

In addition to that, these very dark roasts taste bitter and burnt. Add to that, the residual oil that is stuck in the machine will become rancid. These conditions will lead to the espresso having a foul, unpleasant taste, completely different from the intended rich, strong, and smooth flavour that defines an espresso.

It is more than likely that people who say they don’t like espresso have only tried it from overly roasted coffee beans in a machine that needed some maintenance.

Can Oily Coffee Beans Clog the Grinder

Oily coffee beans can harm your grinder in the same way they can your espresso machine. The excess oils tend to stay in the machine longer and go stale, causing a significant change in taste over time, and making it more difficult to repair the grinder.

Repeated use of oily coffee beans will result in residual oil turning gummy and clinging to your Grinder’s components. This will start from the hoppers being sticky, this will impede the flow of the beans through your grinder. And lead to the grinders clogging up, making the coffee ground stick together, looking clay-like.


Oily coffee beans are overly dark roasted beans, usually roasted beyond the second crack. Despite popular belief, oily coffee beans do not necessarily mean they are fresher than dry beans; they are simply more intensely roasted. 

You should keep in mind that oily coffee beans can clog up your coffee machine, and lead to nasty unpleasant tastes. And a compromised machine that can cost you in repairs or a full replacement.

Paul Mason

coffee blogger

Interested to know more about Hot Coffee? Got a question about our content or perhaps want to make a suggestion? The feel free to contact us today.

We’ll be more than happy to take a look at any comments, requests or queries that you may have. Thanks for your time, and we hope that your next cup of coffee that you enjoy is the best one that you’ve had, every time! 

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