Coffee is one of the most popular beverages consumed worldwide and is amongst the main dietary sources of bioactive compounds. Recent studies have described a positive association between caffeine ingestion and health, including improvement of exercise performance and enhancement of long-term memories in humans. However, from roasting to extraction, the processing of the coffee beans has a significant impact on the profile of bioactive compounds. For instance, roasting results on the reduction of 5-caffeoylquinic acid and trigonelline, while increases the concentration of melanoidins. Another important component is its lipid fraction (known as coffee oil), which can migrate to the surface of the beans and undergo changes in its composition during roasting. This mini-review presents an overview of the composition of coffee, including changes that occur during processing—from green beans to spent grounds, and recent research on its health benefits, with special focus on their antioxidant properties.