Mouth Alcohol Contamination
The idea behind a breath machine is to measure the alcohol just above the aveolar sacs at the base of your lungs. Measuring the alcohol in your stomach or in your mouth will not tell you how much alcohol you have in your blood—your BAC. Only alcohol at the base of your lungs can be used for this purpose.
Now imagine that you put something into your mouth–a mint, a breath spray, a lozenge– that contains alcohol or that resembles or can be confused with alcohol. In this case you can get an elevated, erroneous reading that makes you appear to have more alcohol in your blood than you actually do. And it is important to remember that even a very small amount of alcohol that is directly introduced into the machine from your mouth will have a hugely disproportionate effect on your BAC reading.
Mouth breath contamination is something that has to be avoided at all costs to ensure that you have a proper breath sample being entered into the machine. It is for this reason that the police are supposed to observe you for fifteen minutes before a breath test in order to ensure that you do not place anything into your mouth that contains alcohol or any substance that resembles ethyl alcohol—such as acetone. Breath mints, mouth wash, gum—all and more of these types of substances can contain alcohol and can result in falsely high readings.
GERD, Heartburn, Acid Reflux and Breath Machines
There is another way that you can get a false high reading on a breath machine. Imagine that before your blow you burp. What has happened is that you have just moved alcohol gasses from your stomach into your mouth where they will be falsely interpreted by the breath machine as coming from the base of your lungs. In fact, the alcohol from your mouth and stomach is being added to the alcohol at the base of your lungs and the reading on the machine is necessarily erroneous—and high.
There are many potential sources for mouth-alcohol contamination. One of the more common of these is acid reflux, commonly referred to as heartburn. This is usually caused by a medical condition called hiatus hernia, and is often found among elderly, pregnant or overweight persons. The symptoms are varied but usually involve a painful burning sensation in the chest, sudden regurgitation of acid fluid in the stomach, or belching. The result in a DUI can be a false-high breath machine reading.
It should also be noted that alcohol itself, as well as cigarette smoke can aggravate the symptoms of acid reflux. Acid reflux can also be aggravated or triggered by stress—such as the kind of stress that you experience when you are surrounded by the police and are in the process of being arrested for a DUI!
Because of the prevalence of acid reflux, you should always look into the possibility of this condition existing. Many people are not even aware that they are suffering from it. They will usually say that they have an “upset stomach” or “gas” and take Tums, Tagament or some other antacid to treat it. If this is a constant problem, then there is a good chance you are suffering from a hiatus hernia.
One last comment: Antacids such as Tums or Tagament are designed to neutralize and/or absorb liquids. This can interfere with the normal metabolism of alcohol, thus throwing off the expected absorption rates of the individual—and consequently, any attempts at determining if you have rising or falling blood alcohol, or determining what your BAC was at an earlier point in time.