What Does It Mean For Coffee Beans To Be Oily?

December 11, 2018

Most coffee beans you will see have that dry look to them. That’s just normal coffee beans.

But sometimes you come across some that have a definite oily look about them, a greasy sheen that looks a little strange and you wonder what’s going on…

So what does it mean for coffee beans to be oily?

Well, when they are roasted coffee beans go from a bright green color to a progressively darker brown color. The longer they are roasted, the darker they become, ranging from a light roast to a medium roast to a dark roast.

If coffee beans are roasted to a dark roast, as well as becoming a very dark brown, the heating process makes much of the oils and oily compounds within the bean to come to the surface and give a sheen that looks greasy. Essentially, coffee beans that look oily are dark roasted and should have a dark brown color.

Is this a good thing? What is the best roast for your coffee? So many questions… All of which are going to be answered below 🙂

So what does it mean for coffee beans to be oily?

Coffee beans come from what is essentially a fruit, you can see the ‘coffee cherries’ just after they have been picked from the trees in the photo below:

So inside all coffee beans are naturally occuring oils. When the coffee beans are heated, as in the roasting process, these oils turn from solid to liquid and rise to the surface of the bean. All coffee beans, whether light, medium or dark roast will have some amount of sheen to them shortly after they have been roasted.

As the dark roasts have been heated to the highest temperature and for the longest, these roasts have distinctly more of this sheen to them than the other roasts. They create an oily look that is a little jarring almost for people who are not used to it (which is maybe why you ended up on this webpage!)

Here’s a look at what I mean when I talk about an oily dark roast. There’s a clear sheen to the beans and they are also a dark brown, both a result of the longer roasting process.

Here’s a look at some normally roasted coffee beans to give you a comparison.

One nice positive of oily coffee beans is that you know the coffee was roasted recently. That dark roast you bought will be slick and shiny for several days after the roast but a couple of months down the line it will have all faded along with the taste.

If you aren’t already, buy and brew your coffee within 15-30 days of the roast date for maximum flavor!

Are Oily Coffee Beans A Good Thing? (Better Than Non-Oily)

So if you’ve been paying attention, you now know that oily coffee beans are a result of the roasting process. Heat the beans up to a certain temperature and you get that oily sheen, usually when the beans are quite far into the roasting process in what is called a dark roast.

So the question becomes… is a dark roast better than other roasts?

Dark roasts are known for their smoky, charred taste which many people come to associate with good tasting coffee. That said, in coffee circles this is often considered an inferior roast because it emphasises generic burnt flavors over the inherent flavors of the coffee bean.

Dark roasts can be useful to cover up cheap coffee and they are the mainstay for companies like Starbucks which prioritize caffeinated coffee-based drinks loaded with sugar over coffee that will taste fantastic served just black.

Medium roasts and particularly light roasts are more likely to have fruity, floral or sweet notes that can really make a coffee sing. These kind of roasts are what is high-quality for high quality coffee, whether that is served in a coffee shop or just at home.

For example, the Ethiopian Yirgacheffe is a relatively famous coffee bean that is well-loved for its distinct fruity flavors of lemon and blueberry. Any roaster worth his salt is not going to sell you a Yirgacheffe Dark Roast because you’d lose those inherent flavors that make that coffee so special.

With all that being said, some coffee beans come alive just that bit more with a dark roast. It’s not all cut and dry. And when you add espresso to the mix or look into blends of coffees then there’s a whole load of rules and exceptions that make coffee roasting such an art.

So to sum up, there is no ‘better’ when it comes to coffee because what you prefer is what you prefer and there’s nothing wrong with that. But oily coffee is conventionally seen as a poor roast for ‘good’ coffee and not something that is desirable in many instances.

Advantages Of Having Oily Coffee Beans

Whenever someone speaks to me about coffee beans being oily, it’s always that it’s a negative thing. They look greasy and ruined and undrinkable, they cry.

Well, that’s not really the case, and if you’ve got some oily-looking beans burning a hole in your kitchen cabinet (or whatever) then don’t despair…

While it’s true that I’ve spent half this article discussing why in many cases the oily sheen of a dark roast is often inferior to the coffee beans of the much less oily medium roasts, I’m going to give two big reasons why oily beans are actually pretty darn awesome for making coffee.

1. Recently roasted. So your coffee beans get that dark brown oil sheen when they’ve been darkly roasted, we know that. But that sheen does not last forever. Over time, the oils will degrade and decompose and your coffee beans will go back to being dull looking and dry.

This is a bad thing because coffee beans are at their very best for only a short period. When you roast coffee, they will have their absolute top flavor for 15-30 days depending on how discerning you are.

After this time period, your coffee beans will become stale and mediocre tasting. So enjoy that oily sheen because it means you’ve got fresh coffee that’s at peak flavor.

2. (Probably) made by someone who knows what they’re doing. If we assume that you’ve got your hand onto some oily coffee beans then it’s pretty likely that it doesn’t matter that they weren’t a light or medium roast, because whoever roasted them probably made them a dark roast for a reason.

How do I know this? Well, the majority of coffee that is sold is stale. Go to your grocery store and look up and down the coffee aisle and it will be bags and bag of coffee that has been sitting around in shipping containers and is no longer fresh.

The fact is, high-quality roasted coffee has a short turnaround time to be sold or it will lose flavor. Most mass producers of coffee ignore this and just accept they will sell it stale.

So if you have even got coffee beans that are fresh and have that shiny look then they have probably been bought from an independent roaster that knows what they’re doing, otherwise the shine would’ve gone.

Learn More About Your Coffee Beans

So this article is coming to a close and hopefully you got some good info out of it. I’ve written extensively about the subject of coffee beans and all their idiosyncrasies so I’d like to list a few links here you might be interested in reading.

I’ll even chuck in a general description of what’s going on so even if you don’t click you can learn a little more about the myriad factors of good coffee.

1. What Is Single Origin Coffee? (And Why You Need It In Your Life…)

Single Origin is coffee that comes from a single source, be that a country, region or farm. It’s knpronouncedts more prnounced flavors and is definitely in vogue at the moment. Blends, by contrast, are mixes of different coffee beans that aim to create a certain flavor profile and have a more balanced or smooth taste.

2. What Do Different Coffee Roasts Mean? (Light, Dark, City+, French…)

I’ve covered a decent amount about the terribly important roasting process already so just check out that link if you wanna learn more!

3. What Are Naturally Processed Coffee Beans?

There are two main types of processing the coffee cherries and beans once they are picked from the tree, dry processing or wet processing. The first is a more natural method of drying the cherries out in the sun, like Single Origin this can lead to more pronounced flavors but also can be a little controversial in overdoing it. Wet processing uses machinery and is the more common method.

4. What’s The Difference Between Arabica And Robusta?

These are the two main species of coffee bean that are quite distinct from each other. The majority of coffee you buy will be Arabica, it’s considered the better tasting bean. Robusta is more caffeinated and bitter and finds its place in some espresso blends and certain countries like Vietnam.

5. How The Taste Of Your Coffee Beans Change By Region

Coffee beans vary drastically from region to region. African coffees, which are a favorite in Third World coffee circles, are famous for their fruity and acidic notes like blueberry and lemon whereas Asian coffees are more known for smokier and earthier flavors.


  • Reply pamela February 18, 2019 at 5:33 pm

    v good post. i want a coffee bean that is darkest and oiliest, spanish would perhaps be a good choice. 2 questions: what is the best bean in this category and do i lose the oil in Kcups?

  • Reply Alan Flowers April 25, 2019 at 5:14 pm

    The oiliest bean I’ve roasted in the ONOBEANO available from the coffee bean corral d o t c o m.
    Pan roasted, over a 1/4 gas flame, shake 3x every 4 seconds; use a glass lid so you can see when you reach the oily stage, about 10 minutes. At the end of the roasting, 15 seconds too much will ruin the oil. Now, this is crucial, when you see the oil appear, put the skillet on a block of ice to shut down the roasting process. A 10″ metal cake pan works well. Take the hot glass lid off and put another on one from your freezer; turn it upside down and shake the beans against the inside of the frozen lid. There! My secret is out! I destroyed a lot of green beans before I figured this method out; drinking Kaffee in Germany in the 70’s & 80’s was a revelation.
    Also, This bean makes a great tripple espresso vanilla latte.

  • Reply Erry August 31, 2019 at 6:49 am

    I have solution to make a dark roasting without more bitter, very well for espresso blend , i am using hot air roasting system, only 4 minute was complete just using temperature not more 140 Celcius , if you need dark roasted been without more bitter, whatsapp me at +6285222232019

  • Reply Kathy H September 12, 2019 at 3:19 pm

    Great post very informative, I bought a new coffee at Cash and Carry (Smart Foodservice). There brand “First Street ” dark and crisp Espresso Roast whole beans, It was very dark and shinny (oily). Very different from the other brand I get at Grocery Outlet-“Running Pump Roasting Organic Peru Churupampa. Much lighter and dry. So of course I had questions, so this article was very helpful. Thanks. From Kathy in Seattle-known for its coffee consumption.

  • Reply ian March 17, 2020 at 10:34 pm

    Useful article. I’ve bought a load of oily coffee beans. Good stuff but it seems to be clogging up the grinder in my bean to cup machine which is very difficult to clean. Anyone else had this problem?

    • Reply Sarah H May 31, 2020 at 3:52 pm

      I don’t know the answer, but on a video for a machine like yours from Seattle Coffee Co. website, the person said oily beans are a “no no” in those machines.

    Leave a Reply