How long does it take to pass a breathalyzer after one beer?

In this brief article, we will answer the question, “How long does it take to pass a breathalyzer after one beer?” and how the breathalyzer works.

How long does it take to pass a breathalyzer after one beer?

It would take at least twenty-four hours to pass a breathalyzer test after one beer. It is difficult to estimate how long the alcohol would remain in the body to be detected by a breathalyzer as alcohol metabolism is different for different individuals.

Age, gender, weight, liver condition, medications, and alcohol tolerance can influence the metabolism of alcohol. Breathalyzers can also show a margin of error. This margin of error can go as high as 0.01%.

If an individual consumes only a drink, the alcohol content would be just 0.02%. If the blood alcohol content would be more than 0.2%, it would take at least 13 hours to metabolize the drink.

To avoid being intoxicated, it is essential to wait one hour after consuming each drink. For instance, if you consume a drink at 7 pm, consume the next drink after an hour that is at 8 pm. This is because consuming excess drinks could intoxicate your system.

What is blood alcohol content?

The blood alcohol content is the level of alcohol present in the body. It is written in weight per unit volume and helps in detecting the amount of intoxication in the individual’s body.

A blood alcohol level of 0.2% would indicate that there are 0.2 grams of alcohol per deciliter in blood.

How does the body metabolize alcohol?

The liver contains two enzymes namely aldehyde dehydrogenase and alcohol dehydrogenase. These enzymes would convert alcohol into water and carbon dioxide. These enzymes of the liver can work on only one drink per hour.

When alcohol gets into your body, it is taken in through the intestine and stomach.  Aldehyde dehydrogenase and alcohol dehydrogenase work to metabolize these enzymes to excrete them from the body. 

Alcohol dehydrogenase converts the alcohol to acetaldehyde. The other enzymes also help in the metabolism of alcohol which helps in converting acetaldehyde to acetate. Some of the alcohol would be excreted through urine as well as breath.

The alcohol eliminated through breath is detected by the breathalyzer. The rate at which alcohol is excreted by the liver is 0.15%. If the drinks containing alcohol are consumed quickly, the alcohol starts to accumulate and the blood alcohol content would rise.

Consuming 3-4 drinks an hour could bring the blood alcohol content to 0.08%.

How does a breathalyzer work? 

A breathalyzer contains a positively charged electrode and a negatively charged electrode. When an individual blows into the breathalyzer, the ethanol present in the breath would react with the water present in the air at the negatively charged electrode to form acetic acid. 

In the positively charged electrode, oxygen would form water. The reactions at both electrodes would provide an indication of ethanol present in the breath.

How quickly can breathalyzers detect alcohol in your system?

The breathalyzers can detect alcohol in 15 minutes after you have consumed the drink. Consuming coffee or having a shower would not help in putting off the intoxication. Individuals prone to binge drink alcohol can have it in their system for 10-12 hours.

How are blood alcohol levels classified?

The blood alcohol level in g/100mlCondition of the drinker
0.00-0.05The individuals would appear sober and normal. Some individuals might experience euphoria.
0.05-0.10The individual would start losing inhibitions, concentration, and judgment. The reaction time also gets reduced.
0.10-0.15There is an increased risk of developing emotional instability, inability to walk and balance oneself. Individual experiences memory loss and there is a further reduction in reaction time.
0.15-0.25There is a further loss in memory and the individual is unable to balance or walk properly. There is also a reduced reaction to pain and an increase in numbness.
0.25-0.35Reduced muscle coordination and orientation. Loss of memory along with apathy would also be seen.
> 0.35The individual loses consciousness and can fall into a coma. There is also impaired muscle movement observed. Vital parts of the brain slowly stop functioning followed by cardiorespiratory collapse and death.

Are mixed drinks more intoxicating than wine or beer? 

No, both beer, wine, and mixed drinks have the same amount of alcohol content. They give the same blood alcohol content in a breathalyzer.

Other FAQs about Beer that you may be interested in.

Is beer vegetarian?

Can you live off Beer?

Can you survive on beer without water?


In this brief article, we have answered the question, “How long does it take to pass a breathalyzer after one beer?” and how the breathalyzer works.


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.