A recent study on biological rhythms in the body revealed that the best time to drink a cup of coffee is between 9:30 to 11:30 a.m., according to Fast Company. The article suggests that consumers should not drink coffee when cortisol levels are at their highest due to cortisol’s relation to alertness. Cortisol concentration in the body reaches its peak between 8:00 a.m. and 9:00 a.m., noon and 1:00 p.m. and 5:30 and 6:30 p.m. Full article.