Can breathalyzer detect 1 beer 4 hours after drinking it?

A breathalyzer can detect 1 beer 4 hours after drinking it because alcohol can be detected in the breath for up to 24 hours after drinking. The amount of alcohol that is detected will depend on the person's blood alcohol content (BAC), which is affected by factors such as weight, gender, and metabolism. A standard drink (e.g., a bottle of beer) raises the BAC by approximately 0.02%. For most people, the BAC will return to zero within 10-12 hours of drinking. However, for some people, it can take longer.