However, dark roasts tend to be slightly lower in caffeine after the roasting process. Others have heard that roasting burns off caffeine, meaning light roasts are actually higher in the stimulant. Some people assume that the darker the bean, the higher the caffeine content. There are misconceptions about which roast is higher in caffeine. Therefore, you may wonder whether light and dark roast differ in terms of their caffeine contents. That’s because the caffeine in coffee stimulates brain activity and releases neurotransmitters that make you feel more alert and awake. Many of us reach for a cup of coffee first thing in the morning or when we need quick boost of energy. These variations in roasting account for differences in the color, density, and moisture content of the beans. Summaryĭark roast coffee beans are heated to a higher temperature for a longer length of time than light roast coffee beans. Roasting also brings natural oils to the surface of the beans, which is why dark roasts tend to have a shine. Heating coffee beans removes moisture, so dark roast beans tend to be light and puffy, while light roasts are dense and moist. In short, the lighter the roast, the lower the temperature the beans are roasted at - and the shorter the time they spend in the roaster. Light roasts are typically roasted between 350☏–400☏ (177☌–204☌) for around 10 minutes or less ( 2).ĭark roasts are heated for closer to 15 minutes above 400☏ (204☌).
It sounds like a simple process, but even slight changes in the time and temperature at which the beans are roasted can result in differences in the final product.
Roasting these green coffee beans evokes a variety of chemical, physical, and sensory changes in the beans and is ultimately what gives coffee its quintessential color, aroma, and flavor ( 1).Ĭoffee beans are usually roasted in large rotating drums, in which they’re heated for 5–15 minutes before being cooled and packaged. Before they’re roasted, coffee beans are green fruit seeds of Coffea plants, with little resemblance in color or flavor to the morning beverage we all know and love.