Variability in breath alcohol concentration profiles during controlled social drinking

Controlled alcohol studies often use standardized dosing conditions to characterize absorption and elimination. The present study evaluated breath alcohol concentration (BrAC) profiles under supervised social drinking conditions that permitted variability in beverage consumption and food intake. Forty-two adult participants consumed self-selected 80-proof mixed drinks with ad libitum access to food. Drinking duration ranged from 45 to 172 min (mean 108 min, median 110 min), reflecting substantial variability in consumption time across participants. BrAC was measured at approximately 30-min intervals using an Intox EC/IR II until return to zero. Peak BrAC ranged from 0.040 to 0.117 g/210 L (mean 0.087). Time from the final drink to peak ranged from -23 to 76 min (mean 17 min, median 13 min). The mean elimination rate was 0.0186 g/210 L/hr (SD 0.0027, range 0.0134 to 0.0261). Most participants reached peak concentration shortly after drinking ceased, although delayed peaks of more than 1 hr were observed in some individuals. Representative curves demonstrated variability in absorption timing, including occasional multi-peak profiles, while post-peak elimination was generally linear. These findings characterize the range of BrAC-time patterns observed under supervised social drinking conditions and provide context for interpreting alcohol measurements in applied settings.