Drivers in Arkansas are probably aware that it is illegal for them to be behind the wheel if their blood alcohol concentration is 0.08 percent or higher. However, understanding how much alcohol it takes to reach that point may confuse people, and for good reason.

According to Drugs.com, pinning down the number of drinks a person could have without surpassing the threshold may be challenging or impossible due to quite a number of influences. For example, the amount of body fat a person has, how much he or she weighs, how much water and food are in the system, and other physical factors affect the absorption of alcohol, also known as ethanol.

Another reason for the difficulty is that the amount of alcohol in a single drink varies. Officially, one drink contains 14 grams of ethanol. Starches, sugars and yeast are fermented to create this substance, and that volume of pure alcohol is typically found in 12 ounces of beer, five ounces of wine, an ounce-and-a-half of liquor or about eight ounces of malt liquor.

National Public Radio reports that in some rare circumstances, the Saccharomyces cerevisiae species of yeast involved in the process of creating alcohol is present in the body. People who have this condition, which is called auto-brewery syndrome, may consume starches or sugars and convert them to the same pure ethanol found in an alcoholic beverage. Doctors have monitored patients with the health issue and discovered that their BAC may rise to extremely high levels, even though no alcohol is consumed.