Beer can cause intoxication, which is the psychoactive effect resulting from alcohol in the body. Whether a person becomes intoxicated depends on two primary variables: the concentration of alcohol in the beverage and the speed of consumption. Impairment is a direct function of how quickly the body processes the incoming alcohol compared to the rate of consumption.
What Makes Beer Intoxicating
The intoxicating substance in beer and all alcoholic beverages is a compound called ethanol. Brewers measure the potency of beer using Alcohol By Volume (ABV), which indicates the percentage of the beverage’s total volume that is pure ethanol. Most commercial beers range from 4% to 6% ABV. However, certain craft beers and strong seasonal brews can contain much higher levels, sometimes reaching 12% ABV or more, significantly increasing their potential to cause intoxication.
The Process of Alcohol Absorption
Intoxication occurs when the body absorbs ethanol faster than the liver can metabolize it, leading to a measurable concentration in the bloodstream. Unlike most nutrients, alcohol does not require digestion and is absorbed directly into the bloodstream through the lining of the stomach and, more significantly, the small intestine. This rapid absorption allows the ethanol to travel quickly throughout the body, including to the brain, which is the site of intoxication effects. The level of alcohol in the blood is quantified as Blood Alcohol Content (BAC).
The liver is the primary organ responsible for breaking down ethanol using the enzyme alcohol dehydrogenase (ADH). This enzyme converts the alcohol into a toxic intermediate called acetaldehyde, which is then quickly processed into a non-toxic substance called acetate. The liver can only metabolize alcohol at a relatively constant rate, typically processing the equivalent of about one standard drink per hour. When beer is consumed faster than this fixed metabolic rate, the excess ethanol remains in the bloodstream, causing the BAC to rise.
Personal Factors That Change the Outcome
Several factors unique to each person modify how quickly and severely beer affects them, even if the total amount of ethanol consumed is constant. The presence of food in the stomach is one major factor, as a full stomach slows the rate at which alcohol passes into the small intestine, where the most rapid absorption occurs. This delay allows the alcohol to be exposed to stomach enzymes longer, reducing the immediate surge of ethanol into the bloodstream.
An individual’s body mass and composition also play a role because alcohol distributes itself throughout the water in the body. A person with a larger body mass generally has more total body water, which dilutes the ethanol and results in a lower peak BAC compared to a smaller person consuming the same amount. Additionally, the carbonation found in beer can accelerate the rate of absorption, causing the effects of intoxication to be felt more quickly than with non-carbonated alcoholic beverages.