Note that this post contains affiliate links and we may earn a small commission at no extra cost to you if you buy something.
If there’s one highly debatable subject in the world of java, it’s got to be coffee beans that are more oily. Seriously, you can stumble upon myriads of contradicting information on this topic. Some say that beans that have a greasy look are awesome, while others seem to claim the opposite.
What’s the truth then – are shiny and oily coffee beans good or bad?
Generally speaking, if your coffee beans look oily, the chances are they’re still fresh.
But this largely depends on the roast (light, medium or dark) and the particular type of beans used.
Light roast beans are less oily, while darker roasts tend to have more sheen to them.
And this doesn’t mean one is better than the other.
It’s just that a longer roast i.e. dark roast results in the beans being oilier.
Mostly, the oiliness of the beans starts showing up several days after being roasted.
And that specific shininess goes away after several weeks, no matter the roast process.
In fact, all roasted beans will form some sheen after they’ve been roasted.
That’s perfectly normal and it happens when the inner shell of a coffee bean interacts with oxygen.
It’s just that dark roast beans’ shells brittle as they’ve been exposed to heat for longer.
As a result, they get oilier quicker and they also turn bad faster than lighter roasts.
Table of Contents
Do Light Roast Beans Have Any Sheen At All?
Yes, all roasted beans become oily to a certain degree, sometime after they’re roasted since they’re all exposed to oxygen.
Even lighter roasts will have some sheen to them, just nowhere near as much as darker roasts.
So if the beans you bought aren’t oily, there are two possible scenarios:
- They’re extremely fresh as the oil hasn’t yet surfaced (e.g. a few days old max)
- They’re incredibly stale (i.e. at least a few weeks old) since the oils went away
Subsequently, light roast coffee can stay fresher for longer as opposed to its dark roast counterpart.
That’s because it has been roasted to a lesser extent, thus retaining most of its oils.
But even so, all roasted beans (no matter the roasting method) will start getting oily a few days after they were roasted.
What Causes Coffee Beans To Be Oily?
A chemical reaction between the shell of the coffee bean and oxygen.
This applies to all roast types, be it light, medium or dark.
However, the heat used during the roasting process is what determines exactly how oily the roasted beans will be.
The distinctive cracking noise that the coffee beans make during roasting happens when walls of their shells start to burst. These ‘cracks’ result in the release of oils and gases from the beans. Hence roasting them for longer will make the beans oilier and darker.
Naturally, darker roasts utilize pretty high temperatures (around 450 F degrees) which leads to cracks in the shell of the bean.
Remember how some people prefer to stop roasting after the ‘first crack’, while others go beyond the ‘second crack’?
Yep, this ‘crack’ refers to the cracking sound the shell makes when exposed to heat.
Keep in mind that If the beans are roasted with lower heat (let’s say below 435 F degrees) they’ll retain more oils, resulting in less a less shiny appearance!
Another thing worth noting is that the coffee beans that come from the coffee cherry fruit all carry natural oils inside them.
And when exposed to heat, these oils start leaking from the beans.
It’s just that the more you expose them to heat, the oilier they’ll get – makes sense, eh?
Are Darker Roasts Oilier Than Lighter Ones By Default?
Absolutely, because they’re exposed to more heat.
Now, the easiest way to make your beans as greasy as possible is to overroast them.
This will give you a pretty dark roast, which some people love and others hate.
But we all know that the light vs dark roast debate eventually comes down to personal preference.
Also, if you come across dark roast beans that are LESS oily than lighter roasts, run as fast as you can!
A darker bean that looks dry is a strong indication that all flavor is gone.
Why Is There An Oily Film On My Coffee?
This happens when the coffee that you’ve brewed has more body to it.
And that oily film on your coffee is generally the result of certain brewing techniques that don’t use a filter i.e. French press.
Also, darker roasts will generally produce coffee that’s oilier and has more body.
Coffee scum a.k.a. the oily film on your coffee doesn’t mean that it’s bad or that something’s wrong with it. It all bogs down to aspects like the brewing method used and the type of roast!
However, there are other things that may cause oiliness on top of your java.
Here are the 3 main suspects to look for if coffee scum bothers you:
1. Coffee beans
Certain kinds of coffee beans might have an impact on how oily the coffee might appear.
Note that fresh coffee beans of higher-grade shouldn’t be very acidic.
Thus, higher-grade java that’s not stale (e.g. organic beans) shouldn’t be very oily.
2. Hard water
The calcium found in hard water has the ability to attach to the fats in the coffee, which results in increased oiliness.
This is especially true if the hard water is hot, as it should be when brewing coffee.
In contrast, soft water contains less calcium so it doesn’t give an oily look to your coffee.
3. Roasting technique
Darker roasts might result in an oilier cup of Joe, especially beans that have been roasted on a flame.
This can make your coffee oilier i.e. with coffee scum on top.
On the contrary, beans that are roasted slowly are smoother.
On a side note, don’t forget that all coffee beans contain natural oils inside them.
In fact, the oil found in coffee beans is made of 71% fats that are comparable to the ones you’ll find in soaps or margarine.
Simply keep in mind that some brewing methods, roast types and the water quality might affect the oiliness of your java.
Are Shiny Coffee Beans Better?
Generally yes, although it depends on the roast.
Darker roasts have more sheen, while lighter ones have a more dull shininess to them.
Regardless, if the coffee beans are fresh they’ll inevitably have some sort of sheen to them.
The oil that covers the coffee beans after they’ve been roasted will slowly evaporate when in contact with air. Or in other words – stale coffee will NOT be shiny or oily!
In short, the beans that are exposed to heat longer will produce more oil, simple.
That’s why darker roasts look so shiny when compared to their lighter counterparts.
Keep in mind that the coffee beans that you’re buying do need to have some sheen, whether they’re a dark or light roast.
Now, If you bought coffee beans that have zero sheen, not even the dull shininess of light roasts, they’re probably stale.
The only exception to this rule is probably decaf beans that were decaffeinated using only water.
These will look quite dull by default.
How Do You Know If Coffee Beans Are Bad?
Use your nose – smell it.
If the yummy aroma and taste aren’t present, the beans are no good. Another thing is to check the roast date.
If the beans were roasted 4 weeks ago (1 month), then avoid them.
Always use roasted coffee beans within a month after they’ve been roasted for the best taste and flavor!
For the most part, coffee beans are at their finest somewhere from 3 to 10 days after they’re roasted.
Here’s A Great Trick To Tell With Certainty If Your Whole Beans Are Stale!
- Pour half (1/2) a cup of the whole beans in a ziplock bag
- Press all the air out of the bag
- Seal the bag and leave it overnight
- Check it in the next morning
- A bag that’s puffed with air = fresh whole beans!
- A bag that’s flat = stale whole beans!
It’s worth mentioning that this method is only viable for whole coffee beans.
We already discussed what to look for in terms of whether or not your roasted beans are fresh.
So, to make sure that we’re on the right track here – darker roasts are shinier than lighter ones.
This happens because the beans are exposed to more heat when the roast is dark.
As a result, they look oilier.
And a darker roast doesn’t necessarily mean that it contains more caffeine.
The caffeine content of dark roast coffee is about the same amount of caffeine as lighter roasts.
The bean type is what truly counts i.e. Arabica or Robusta!
Nonetheless, both dark, medium and light roasts will have some shininess to them if they’re fresh.
The natural oils that come out after the roasting process literally evaporates after several days.
Thus, some oiliness is actually good is the means the beans were roasted recently.
Now, are you personally a fan of oily coffee?
Or do you prefer the lighter roasts that aren’t as oily?
We’d love to know so drop a comment below!