Coffee is slightly acidic (pH 5.0–5.1[1]) and can have a stimulating effect on humans because of its caffeine content. It is one of the most popular drinks in the world.[2] It can be prepared and presented in a variety of ways. The effect of coffee on human health has been a subject of many studies; however, results have varied in terms of coffee's relative benefit.[3] The majority of recent research suggests that moderate coffee consumption is benign or mildly beneficial in healthy adults. However, the diterpenes in coffee may increase the risk of heart disease.[4]