A 15 minute observation is required before every evidentiary breath test. The purpose of the observation period is to eliminate the possibility of alcohol in the mouth being measured as alcohol from the breath. If this were to happen the breath test result would be too high. The test subject must be observed for at least 15 minutes before the breath test to ensure the subject does not consume anything nor burp, beltch or regurgitate. The observation period must be re-started if the subject consumes anything or burps.