The amount of wine required to cause intoxication varies significantly from person to person. Intoxication is a temporary state resulting from alcohol consumption that leads to impaired judgment, reduced motor skills, and altered mood. While the strength of the wine matters, the primary drivers are the individual’s physiology and the speed of consumption.
Defining the Measure: Standard Servings and Alcohol Content
The foundation for estimating consumption is the “standard drink,” defined in the United States as containing 0.6 fluid ounces (14 grams) of pure alcohol. For wine, this typically equates to a five-ounce (148 ml) serving glass, assuming an Alcohol By Volume (ABV) of 12%.
Wine ABV varies widely, ranging from 5.5% for some sparkling varieties to 15% or more for robust reds. A five-ounce pour of 15% ABV wine contains significantly more pure alcohol than the standard definition, equating to about 1.25 standard drinks. Furthermore, many people pour servings larger than five ounces, accelerating the rate of alcohol intake.
The Science of Intoxication: Blood Alcohol Concentration
The objective measure of intoxication is the Blood Alcohol Concentration (BAC), which reflects the percentage of pure alcohol in the bloodstream. Alcohol is absorbed directly into the bloodstream, with 20% absorbed through the stomach and 80% through the small intestine. Since alcohol does not require digestion, its effects are felt rapidly.
The liver processes alcohol using enzymes like alcohol dehydrogenase (ADH) to break it down. This occurs at a relatively fixed rate, averaging about 0.015% BAC per hour, meaning the body metabolizes roughly one standard drink per hour. When consumption outpaces the liver’s metabolic capacity, the BAC rises, leading to intoxication.
Different BAC levels correspond to predictable effects on the central nervous system. A BAC between 0.02% and 0.05% results in mild euphoria and minor impairment of judgment. As the level approaches 0.08%, the common legal limit for driving impairment, coordination, speech, and balance are noticeably affected. Rapid consumption causes alcohol to accumulate, pushing the BAC higher and increasing impairment.
Personal Factors Influencing Absorption
The rate at which wine raises BAC is modified by several biological and behavioral factors.
Body Mass and Composition
Body weight and composition play a significant role because alcohol is diluted by the total volume of water in the body. Individuals with greater body mass generally have more body water, which dilutes the alcohol more effectively, resulting in a lower peak BAC after the same amount of wine.
Biological Sex
Biological sex is another primary variable, as women typically experience a higher BAC than men after consuming equal amounts of alcohol. This is partly due to women generally having lower body water content and lower levels of the stomach enzyme ADH.
Food Consumption
The presence of food in the stomach significantly slows the absorption rate of alcohol. Drinking wine on a full stomach delays gastric emptying, preventing rapid passage into the small intestine where absorption is quickest. Foods rich in protein or fat are effective at slowing absorption, leading to a lower and more gradual peak in BAC. Conversely, drinking on an empty stomach causes a rapid spike in BAC and a faster onset of intoxication.