Many people arrested for DUI in Texas are familiar with the term “mouth alcohol,” but wonder whether it is a valid defense or more of an urban myth.  Because the most compelling piece of evidence used by prosecutors in most Texas DUI cases is a failed breathalyzer test, the accuracy of blood alcohol concentration (BAC) test results obtained through breath testing is an extremely important issue in most DUI cases.  Mouth alcohol represents one of the most significant causes of inaccurate BAC breath testing.

The term “mouth alcohol” refers to residual alcohol that lingers in the mouth that has not yet been absorbed and metabolized by the body.  Breath testing devices used by law enforcement do not actually measure the volume of alcohol in one’s blood.  Rather, the device measures the alcohol in breath from the deep lung tissue and converts this using a mathematical ratio to the concentration of alcohol in the blood.  The fundamental issue that makes the presence of mouth alcohol so critical is that alcohol that has not yet been absorbed and metabolized by the body will have a much higher BAC level than alcohol that has been metabolized before being expelled from the deep tissue of the lungs.

Although law enforcement officers engage in specific procedures to minimize the risk of mouth alcohol distorting a breath test result, these measures do not address all potential mouth alcohol issues nor do officers always carefully adhere to these procedures.  Texas law enforcement officers are required to observe a mandatory waiting period of fifteen minutes before administering the breath test.  The risk of residual alcohol lingering in the mouth if food or drinks being ingested is the rationale for imposing this waiting period.  The officer is expected to continuously observe you during this period so that the officer can ensure no food or beverages are consumed and so that he can note a belch, vomiting or regurgitation, which could cause undigested alcohol to be present in the mouth.

In practice, officers frequently engage in other activities during this period so they are not carefully observing the DUI suspect.   When the officer is watching closely, the officer still may not realize that a motorist who has been pulled over has belched or suffers from acid reflux (GERD).  If you have a medical history of GERD or acid reflux, this may provide a basis for challenging the BAC test results in your DUI case so you should let your Texas DUI attorney know about this aspect of your medical history.

There also are other forms of mouth alcohol that this observation period cannot address.  For example, alcohol can be trapped in dental work like a filling or cap, which could cause an erroneous breath testing result.  If you are arrested for driving under the influence (DUI), Texas DUI attorney Alex Tyra offers a free consultation during which he can advise you about your legal rights and potential strategies for avoiding a DUI conviction.  We invite you to contact us in our Longview office at 903-753-7499 or visit our website and submit a case contact form.