Alcohol absorption and elimination vary considerably amongst individuals, and are subject to influences from a variety of factors. The effects of alcohol concentration and beverage mixer type on the rate of alcohol absorption, in a controlled environment was studied.

21 subjects (12 male, 9 female) consumed a solution containing alcohol, on three separate occasions. The three solutions were, A: Neat vodka (37.5 vol%), B: Vodka mixed with still water (18.75 vol%), C: Vodka mixed with carbonated water (18.75 vol%). The volume of alcohol each subject consumed was determined by Widmark’s equation. The alcohol was drunk in a 5 min period following an overnight fast and breath alcohol concentrations were measured over a 4 h period using a breathalyser.

20/21 subjects absorbed the dilute alcohol at a faster rate than the concentrated alcohol. The difference between the absorption rates was found to be significant (p < 0.001).

The use of a carbonated mixer had varying effects on the alcohol absorption rate. 14/21 subjects absorbed the alcohol with the carbonated mixer at a faster rate, with 7 subjects showing either no change or a decrease in rate. The mean absorption rate for solution C was 4.39 ± 0.45 (mg/100 ml/min), and the difference between this absorption rate and that with the still mixer (1.08 + 0.36) was significant (p = 0.006).