The answer to whether flat beer can still cause intoxication is straightforward: yes, it absolutely can. The term “flat” refers to the loss of carbonation, which is carbon dioxide escaping from the liquid. This process does not alter the amount of ethanol dissolved within the beverage. The intoxicating power of any alcoholic drink is solely determined by its Alcohol By Volume (ABV), and that concentration remains stable even after the bubbles disappear.
The Constant Amount of Alcohol
The concentration of alcohol in beer is fixed during the fermentation process, which creates ethanol as a byproduct of yeast consuming sugars. Ethanol is a stable liquid that remains dissolved in the water content of the beer, regardless of whether carbonation is present. Unlike carbon dioxide, which is a gas that easily escapes, the alcohol molecule does not float away. The Alcohol By Volume listed on the container will not diminish just because the beverage has gone flat. If a beer is 5% ABV, it still contains 5% alcohol whether it is fizzy or not, meaning the full potential for intoxication is preserved.
How Carbonation Affects Alcohol Absorption
The main difference between drinking carbonated and flat beer lies in the rate at which the alcohol enters the bloodstream. Carbonation, or the presence of dissolved carbon dioxide, affects the body’s absorption process. When a person drinks a fizzy beverage, the gas released in the stomach creates pressure that accelerates gastric emptying. Since the small intestine is the primary site where alcohol is absorbed, delivering the ethanol there more quickly leads to a faster rise in Blood Alcohol Content (BAC). Therefore, a carbonated beer can induce a feeling of intoxication more rapidly than a flat beer, even though the total amount of alcohol is identical.
The Practical Drinking Experience
The practical experience of drinking flat beer also influences the rate of intoxication through behavioral factors. Flat beer is often perceived as stale and less palatable than a cold, fizzy one. This decrease in sensory appeal naturally causes most people to sip a flat beer much more slowly. The slower rate of consumption means the body receives the ethanol over a longer time window, allowing the liver to metabolize the alcohol more consistently. This slower intake prevents the rapid spike in BAC that occurs when a person quickly consumes a more refreshing, carbonated drink.