Should Coffee Beans be Oily for the Best Taste?
Even some of the most die-hard coffee fans don't know the ideal look and feel of coffee beans. Some are dark; others are light. They can be dry, oily or cracked, and the intensity of their smell can vary. The truth is, there's no one answer to the question of how beans should look. Many different factors influence their characteristics - including whether or not they should be oily.
Why does oil form?
Throughout the roasting process, coffee beans undergo a chemical reaction that causes their cell walls to burst - hence, the crackling noise that sounds when roasting coffee beans. This releases the gases and oils inside them, and it's also one of the reasons why coffee needs time to settle upon roasting. It needs some time to release all of its contents for the best end result. However, let it sit for too long, and it could become stale. For the best balance, enjoy coffee anywhere from a few days to a week after roasting, or keep the beans stored in a sealed bag to keep them from being exposed to oxygen.
"The color of coffee beans depends on how much oil they contain."
How does oil affect taste?
The color of coffee beans depends on how much oil they contain. Darker roasts are typically oilier in nature, so an extra oily bean doesn't necessarily mean it's fresher than a lighter, dryer one. However, if a darker bean is especially dry, it's most likely a sign that it's gone bad.
Dark, oily coffee beans are typically strong tasting, bold and bitter. On the other hand, dry, light colored beans can be described as overly sweet and flavorless. Again, this is more dependent on the color of the coffee bean rather than its moisture levels. If you're looking to brew a batch of coffee that all parties will enjoy, it's hard to go wrong with a medium brew that's only slightly oily.
The longer a bean is roasted, the more sugar will burn off. This is why darker roasts are considered more bitter and less floral or fruity than lighter roasts. Spice, smoke and other strong tastes remain the same regardless of the roasting duration. The more you learn about your beans, the closer you'll be to finding the roast of your dreams.