The Real Reason Some Coffee Beans Are Shiny

In the early morning when you're just starting the day, you open the brand new package of whole coffee beans from your favorite roastery. The distinct smell of the coffee rises from the bag, filling the kitchen with robust scents and flavor notes. Even just the smell begins to wake you up and make your tastebuds excited for the hot, delicious coffee headed their way. You pour the beans into your grinder. The light hits the beans, which seem to glisten. Actually, the sheen is a little more than you're used to on the coffee you usually buy. Why are the coffee beans so shiny?

Coffee is second only to water as the beverage most Americans drink daily, and around 2.25 billion cups are consumed worldwide each day (via Perfect Brew). More and more people are buying whole bean coffee than ever before, according to a 2020 report by CNN, with whole bean sales growing at a faster rate than ground and instant coffee. The particular characteristics of whole bean coffee, such as the shine on some types of beans, might be unfamiliar to some consumers. However, a shiny coffee bean is completely normal and nothing to be worried about.

The source of coffee bean shine

Some types of coffee beans will seem to have a shiny coating, and that is perfectly normal, natural, and safe to consume. It is a result of the coffee roasting process and the chemical structure of the coffee itself (via El Molino Coffee).

During roasting, flavor oils and lipids are brought to the surface of the coffee on a cellular level. Over time after the roasting, these oils and lipids create shininess on the beans. Not all coffee will have this sheen: darker roast coffee typically develops more oil that rises to the surface, while lighter roast coffee develops less. The oils will also evaporate in an oxygen environment.

If your dark roast beans aren't shiny, that's not a problem, either, and there are a few possible explanations. The coffee won't shine if the beans are freshly roasted and haven't had time for the oils to come to the surface, nor if they are old coffee beans and the oils have evaporated, nor if the coffee was "baked" slowly over a long time and the oils evaporated during roasting. In any case, you are good to grind and make a steaming cup of joe to bring a shine to your day, whether the beans shine or not.