Do Oily Coffee Beans Affect the Taste of Coffee?

This post contains affiliate links to products. We may receive a commission for purchases made through these links. But it never influences our product selection process.
Spread the love

When you’re in the market for good coffee, you may have noticed that some coffee beans are more “oily” than others.

But what is the real reason behind the oiliness of some coffee beans? Does it change the taste of your coffee?

In this article, we’ll break down why is your coffee beans oily, as well as the impact that oiliness has on the flavor of your coffee.

From the effects of the coffee roasting process to the type of coffee bean used, we’ll examine the various factors that contribute to the oily sheen of coffee beans.

Some Common Reasons Behind the Oiliness of Coffee Beans

Do Oily Coffee Beans Affect the Taste of Coffee? 1
Oily Coffee Beans

Coffee beans are the seeds of a fruit, and like other fruits, their appearance can vary from one variety to another.

Whether the coffee beans are oily or not is determined by their variety, their growing conditions, and the roasting process.

Naturally Oily Coffee Bean

Different varieties of coffee beans have different levels of oiliness. For example, Arabica beans are more oily than Robusta beans.

This is because Arabica beans are grown in higher altitudes, where the air is cooler and drier. This environment results in less oil production in the beans.

Coffee Beans Roast Level

When coffee bean is harvested, farmers cover them in a protective layer of surface oil. This layer of oil helps protect the bean from the elements while processing, and the coating also helps to preserve the flavor of the green coffee bean.

As the green oily coffee beans are roasted, the oil is cooked off, leaving the bean dry and crunchy (initially).

However, coffee beans contain oils inside them where all the flavors, amino acids, antioxidants, and caffeine contents reside. This coffee oil starts coming out as it is roasted from the endosperm to the surface of the coffee bean.

Dark roast beans tend to be more oily than light or medium roast beans, as the higher temperatures and long roasting times cause more oil to be released from the beans.

Dark Roast vs Dark Beans

When it comes to dark beans, the oils are not released during the roasting process, but rather during the brewing process.

The oils in dark coffee beans are released when the beans are ground and exposed to hot water, which causes them to “bloom” and release their oils.

The oils in dark beans are what give them their deep, rich flavor.

Processing Techniques

How the coffee roasters process beans can also affect the level of oiliness in coffee beans.

Wet-processed coffee beans, for example, tend to be oilier beans than dry-processed beans, as the wet-processing method leaves more of the oils intact.

Storage Conditions

Coffee beans that are stored in warm, humid environments will release more oils, according to a study on Molecules Journal, resulting in oily coffee beans.

Also, the oils in your coffee bean will begin to leak if they have been stored on a shelf at the store for a long period. This is why we suggest buying recently roasted coffee.

The Chemistry Behind Oily Coffee Beans

Oily coffee beans are the result of the coffee roasting process, and the chemistry behind it is fascinating.

When coffee beans are roasted, the bean’s outer layers undergo a chemical reaction called Maillard Reactions.

This reaction occurs when the heat from the roaster causes the proteins and sugars present in the bean to break down, forming new compounds and producing the characteristic aroma and flavor of the coffee roasts.

During the roasting process, oils are released from dark roast coffee beans, which is what gives coffee beans their trademark oily texture.

The oils are composed of triglycerides, which are fatty acids that are responsible for the coffee’s flavor and aroma. These triglycerides are broken down by the heat of the roaster, and the oils are released.

The oils released during the roasting process also contribute to the unique flavor of the coffee. The oils contain compounds called esters which provide coffee with its characteristic flavor.

These compounds also interact with the proteins and sugars present in the beans and contribute to improving flavor.

It is important to note that the oils released during roasting can be harmful if they are not handled properly. They need to be stored in an airtight container and kept away from heat and light, as these will cause the oils to break down.

If the beans are not stored or handled properly, they can contain rancid oil, leading to off-flavors and a less-than-ideal cup of coffee.

Are Oily Coffee Beans Good or Bad?

Do Oily Coffee Beans Affect the Taste of Coffee? 2
coffee beans

Now that we understand the underlying reasons behind shiny coffee beans, the question comes “is this a good thing or bad?”

Oily coffee beans have been a subject of debate among coffee aficionados for some time now.

On one hand, some believe that the residual oil on the beans helps to improve the flavor and texture of the final cup. On the other hand, some say that oil can ruin the flavor and make the coffee taste unpleasant.

The truth is that ideal coffee depends on how you prefer it.

Many people find that the added coffee oil on the over-roasted beans can give a more intense flavor to the final cup of coffee, making it more robust and full-bodied. This is especially true for dark-roasted coffee beans and espresso blends.

Some people don’t like the oily texture of roasted coffee beans and may find that it detracts from the flavor of the coffee.

Another factor to consider is the freshness of the beans. If the beans are fresh, the oil on them will help to lock in the flavor, ensuring that the coffee tastes better for longer.

However, if the beans are old and the oil has had time to oxidize, the flavor of the coffee will be affected.

For some people, oily coffee is difficult to digest. So, you may want to start with a light roast if you’re not accustomed to drinking coffee oils from long roast.

What Are Some Problems with Oily Beans?

Do Oily Coffee Beans Affect the Taste of Coffee? 3

Oily coffee beans can sometimes cause weird problems:

Bitter Taste

The first issue with oily coffee beans is that they can produce a bitter taste. This is because the oils can interact with the acids in the beans, creating a bitter flavor.

While some people may prefer the taste of a bitter cup of coffee, it isn’t for everyone.

Also, the bitter taste can be intensified if the beans are over-extracted. Therefore, it’s important to use the right burr grinders and water temperature when brewing coffee.

Clog Filters

Another problem with oily beans is that they can clog filters.

This can be a particular issue with metal filters, as the oils can get stuck in the small holes and block the flow of water. This can result in a weak, watery cup of coffee.

If you’re using a paper filter, the oils may not block the flow of water, but they can still affect the taste of the finished product.

Damaged Equipment

Oily beans can put extra strain on your grinder or espresso machine.

This is because the oils can collect in the brewing chamber and other parts of the espresso machine, making it difficult for the water to pass through.

If this happens, the automatic coffee machines may need to be taken apart and cleaned. This can be a time-consuming process and can also lead to expensive repairs.

When Should You Pay More Attention to Oily Beans?

If you have a fully automated expresso maker!

The machine grinders inside the espresso machine might be fussier. Oily bean tends to adhere to the walls of the grinder which will gradually impair the performance of your machine.

Continued usage of oily beans may result in exorbitant maintenance costs (regular cleaning) and equipment downtime. It may also alter the flavor of your espresso and result in an unpleasant aftertaste.

That’s why we don’t recommend using very dark roasts (more oily) for espresso machines. You can instead use a French press with medium-dark roasts.

How Can I Prevent Oily Coffee Beans Problems?

Even if you love a bold coffee with all the natural oils, too much oil can cause your coffee to taste bitter.

Here are some tips on how to prevent oily coffee beans:

Choose the light to medium roast coffee – The darker the roast, the more surface oil will be released. Choose a light-roasted coffee or medium-roasted coffee for the best flavor and the least amount of oil.

Buy fresh coffee grounds Older coffee beans start to lose their flavor and oils as soon as they are roasted. Buy freshly roasted beans or coffee grounds from a reputable source.

Use pre-ground dark roast – Pre-ground dark roast coffee beans can be used as an alternative to freshly roasted coffee beans. Grinding your beans just before brewing will help to keep the oils locked in the beans and not released during the brewing methods.

Clean your coffee makerOils can build up in your coffee maker over time. Regularly cleaning your coffee machine with vinegar or a special cleaner will help to remove any built-up oils. Or you can instead use a manual burr grinder.

Store properly – It’s important to store your beans in a cool, dry place to keep the oils from going rancid or becoming low-quality coffee beans. An airtight container is best. You can read this article on storing coffee beans for more advice on this.

Don’t use flavored coffee beans – Flavored coffee beans tend to have added oils and other ingredients that can increase the risk of oily beans. If you want a flavored coffee, it’s best to purchase unflavored beans and add the flavor yourself.


Are Starbucks Beans Too Oily?

Starbucks coffees tend to be more on the oily side. This is because the roasting process used to create Starbucks coffee beans is “dark roasting,” which leaves an oily residue, but has a stronger, more intense flavor. However, Starbucks also offers light roast and medium roast coffee beans.

How to Dry Oily Coffee Beans?

To dry oily coffee beans, you can either spread them out on a baking sheet and bake them in the oven at a low temperature (200 degrees Fahrenheit or lower) for 15-20 minutes, or you can use a food dehydrator set to the same temperature. Make sure to stir the beans occasionally to ensure even drying.

Relevant Reads

Table of Contents