Attorney at Law


James Parker
February 16, 2022
Last reviewed by
August 16, 2023

What Is Absorption?

Absorption describes the process by which alcohol is absorbed into the body and broken down. This process begins with small amounts of absorption occurring in the mouth. Once swallowed, the alcohol will be absorbed in the stomach and small intestine into the bloodstream. From there, the process concludes in the liver which converts the alcoholic compound ethanol from the blood into carbon monoxide and water, excretes them as waste by way of the kidneys and lungs.

There are many factors that can impact the rate of absorption. The most obvious factor is how much alcohol was consumed. The more alcohol consumed, the longer it will take for the body to absorb it all completely. Another key element of absorption is actually food. It has been stated that food can impact the body’s absorption rate in multiple ways. First, the food can physically obstruct the stomach lining that would otherwise absorb the alcohol. Second, the food can hold the alcohol in the stomach for longer before moving into the small intestine, where the most absorption can occur. 

In addition to food and quantity, who is drinking can also impact the absorption rate of alcohol. According to the National Institute on Alcohol Abuse and Alcoholism, women can have a higher concentration of alcohol in their blood despite consuming the same volume of alcohol as their male counterparts. This is due to the fact that women typically have less body water than men and therefore there is less dilution of the absorbed alcohol. 

The final factor in alcohol absorption is adipose levels. People with more fat cells can actually block the alcohol’s absorption, causing the alcohol to accumulate more slowly in the leaner parts of the body. 

Key Takeaways

  • The process of absorbing alcohol into the body and processing it can unduly influence the reading on a breathalyzer test. 
  • The BAC reading returned from a breathalyzer test can be influenced by biological sex, whether or not you have eaten, unabsorbed alcohol, body composition, and weight
  • While alcohol is being absorbed into the blood, a breathalyzer may return a higher result than if the results were taken after the alcohol had been completely absorbed, even if it has not yet been processed by the liver.
  • If you have been charged with driving under the influence on the strength of a single breathalyzer test, an experienced DUI attorney may be able to improve the outcome of your case by leveraging experience and expert testimony.

Absorption and Driving Under the Influence (DUI) Charges

Alcohol absorption rates can significantly impact whether or not a driver is charged with driving under the influence (DUI). As alcohol is absorbed into the body, there is a phenomenon known as the “rising window.” During this window of time, a driver’s blood alcohol content (BAC) level will increase steadily as the alcohol they have consumed is absorbed into their body. This increase occurs despite the fact that the driver is not drinking any more alcohol. If a breathalyzer test is administered during this window, their BAC level will be inflated even if the individual’s behavior and cognition are unaffected.

Most individuals who drink alcohol take one to three hours to fully absorb it into their body. During that time, alcohol from the bloodstream is absorbed into the liver, kidneys, and lungs. The alcohol in the lungs is approximately 8% of the alcohol in the blood. It becomes trapped in the lungs because ethanol, the main compound in alcohol, will evaporate when it comes into contact with air. This scientific principle is the basis for breathalyzer tests. 

The issue with this principle is that it presumes that the alcohol evaporated in the lungs is an accurate demonstration of how much alcohol is in the bloodstream. However, variations in body types and biological sex can impact how rapidly alcohol is absorbed and therefore can influence the breathalyzer results. Additionally, if the individual taking the breathalyzer test burps or vomits, then the breathalyzer will not actually be taking a measure of the alcohol absorbed by the lungs, but instead will take a sample of the lingering acids in the mouth. 

Understanding how the body’s rate of absorption affects the results of a breathalyzer can be the difference between wrongful conviction, and vindication.

The Impact of Absorption on DUI Charges

Alcohol absorption rates play a significant role in driving under the influence (DUI) charges, and understanding this process is essential for those facing such charges. The "rising window" phenomenon is crucial to comprehend, as it can lead to inflated blood alcohol content (BAC) levels on breathalyzer tests, even when an individual is not actively consuming alcohol.

During the "rising window," the body continues to absorb alcohol after consumption has stopped, leading to a steady increase in BAC levels. This can occur over a period of one to three hours after drinking. As alcohol is absorbed into the bloodstream, it also gets trapped in the lungs and evaporates when it comes into contact with air, forming the basis for breathalyzer tests.

However, variations in body types, biological sex, and other factors can impact the rate of alcohol absorption, leading to discrepancies in breathalyzer results. For example, women may have higher BAC levels than men despite consuming the same amount of alcohol due to differences in body water content. Additionally, the presence of food in the stomach can slow down alcohol absorption, leading to delayed BAC increases.

The accuracy of breathalyzer tests can be affected by various factors, such as burping or vomiting, which can lead to inaccurate readings by detecting lingering acids in the mouth rather than alcohol in the bloodstream. Moreover, the rate at which the body absorbs alcohol can unduly influence breathalyzer readings, potentially leading to wrongful convictions if not adequately addressed.

Bottom Line

If you’ve been charged with driving under the influence even though you had not had anything to drink for hours, it is possible that the breathalyzer may have detected alcohol that was still being absorbed into your body. It is crucial that you find an attorney who has worked with other DUI cases like this in the past so that they can present evidence that demonstrates that your specific circumstances, build, or biology are to blame for the incorrect breathalyzer results and argue for the best possible results for your case.

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