Text: Scientists, specifically biochemists, and martini connoisseurs have investigated the difference between a martini shaken and a martini stirred. The Department of Biochemistry at the University of Western Ontario in Canada conducted a study to determine if the preparation of a martini has an influence on their antioxidant capacity; the study found that the shaken gin martinis were able to break down hydrogen peroxide and leave only 0.072% of the peroxide behind, versus the stirred gin martini, which left behind 0.157% of the peroxide. Thus a shaken martini has more antioxidants than a stirred one. The study was done at the time because moderate consumption of alcohol appears to reduce the risk of cataracts, cardiovascular disease, and stroke.

Question: is there a difference between shaken and stirred?
yes