Can Mouth Alcohol Cause False DWI Readings?

January 1, 2017 | By Shane Phelps Law
Can Mouth Alcohol Cause False DWI Readings?

Even after having just a couple of drinks, the lining of your mouth can still contain traceable amounts of alcohol that can be detected by a breathalyzer test. These trace amounts can sometimes register at a level that exceeds the legal BAC limit. In this blog, we explain how “mouth alcohol” can cause a fake DWI reading.

A breathalyzer reader acts on assumption, meaning it always thinks the breath that is being analyzed has come directly from a person’s lungs. However, since the device only measures breath, it cannot accurately account for the amount of alcohol in a person’s blood. Trace amounts of alcohol in a person’s throat or mouth can significantly impact the machine’s BAC calculations, despite the device not being able to locate where the sample is coming from.

Alcohol can stay in one’s mouth and throat for over 20 minutes after consumption. So if a person walks out of bar after washing with mouthwash, they can be subjected to a DWI arrest if their breath is tested with a breathalyzer. In addition to the complications that mouthwash can pose, belching can cause liquids and gases from a person’s stomach to rise into the soft tissue of their throat and mouth. Acid reflux can also cause a false reading. All of these things can directly impact the results of a breath test. For this reason, police are required to observe a suspect for at least 15 minutes before administering a breathalyzer test.

Another thing that is often over looks is a person’s dentures. Traces of alcohol can remained trapped in dentures for up to 20 minutes. Periodontal disease also can trap alcohol in your gums for extended periods of time. Both of these things can create false breathalyzer readings.

Were you administered a breathalyzer test that may have registered a false reading? Contact our College Station team of DWI attorneys to find out how we can help with your case today.