Ever open up a fresh bag of coffee to be unexpectedly greeted with oily coffee beans? You might've wondered what this means. Is this a sign of high quality roasting or have these beans gone rancid. The answer may not be as straightforward as you think. This article will go over exactly why coffee beans get oily and how to tell whether it's a good or bad thing.
In order to determine the reasons behind your oily coffee beans you must look for a few factors.
Most of us are aware that there are many different types of coffee roasts. The most common are Light Roast, Medium Roast, and Dark Roast. When a coffee beans are subject to heat, they naturally go through many chemical reactions.
Oily coffee beans are exactly what they sound like. They are coffee beans that are coated with a layer of oil. The oil is a result of the lipids (fat) within the bean rising to the outer layer of the bean in the form of oil. Depending on the roast, this oil could be completely normal or could be something you need to watch out for.
What to look for in oily coffee beans
Just because your coffee beans are oily does not necessarily mean the coffee beans are of high or low quality. Rather you must investigate a little bit deeper to determine if the oily coffee beans are fresh or not.
Dark roasted beans are more likely to be oily. This is a good sign and it means the coffee beans are fresh and typically of high quality. For example, take a look at Carta Coffee Merchants who are best known for their top shelf Kona Coffee. Their dark roasted Kona is a prime example of how oil beans can be an indication of quality. Note the oily goodness of this particular coffee bean.
Oily coffee beans can also be a sign that the beans have been recently roasted.
However, if the beans are of a light or medium roast and are oily, this could be a sign that the coffee beans are old and stale. Perhaps the beans are past their expiration date, or have not been properly kept in a sealed container. In either case, it truly depends on which type of bean you are examining to determine whether the beans are of high quality when oily.
Misconceptions about oily coffee beans
There are a lot of misconceptions about oily coffee beans and some think that the more oily the bean the better the roast. As mentioned previously, the answer isn't so simple.
The flavor from coffee comes mostly from the oil found within the bean, thus it would make sense that the greasier the bean, the better the flavor. However, in many cases it is best for the flavor to stay within the bean. This is because once the oil hits the surface of the bean it encounters oxygen. This causes the oil to oxidize and the oil loses its flavor complexity – ultimately leading to unpleasant flavors in the roast. Again, this all depends on which type of roast you are examining.
- Did you know that without the oil that's released from coffee during roasting, espresso would have no “crema”. Crema is that foamy layer that espresso lovers have come to prize.
- Within the roasting process there are first and second cracks (which are self-explanatory). Oils are released during the roasting process after the “second crack”. Therefore, coffee that doesn't have a 2nd crack will naturally not be oily.
The main two factors when determining what makes a coffee bean oily are how long the beans have been roasted, and how long the beans have been stored in storage. Once you are able to determine these two factors, you can then determine if the beans are still of high enough quality to produce a quality cup of coffee or whether it's best just to throw them out.
As we mentioned at the beginning of this article, it's not a simple matter of good or bad when it comes to oily beans.
Your best assets when determining the quality of the beans are your eyes and nose – use your best judgement.
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