Memphis Breathalyzer Tests

We live in an age remarkable for its precise scientific instruments. Astronomers tell us they can not only find planets orbiting stars dozens or even hundreds of light-years away, but even tell us what kind of atmosphere those worlds might have; electron microscopes allow medical researchers to examine the structure of a single virus or to map the human genome; some high-speed cameras can record up to a trillion frames a second, fast enough to catch light waves in slow motion.

A police officer can ask you to blow into a small device that – supposedly, at least – will measure alcohol in your blood down to a tiny amount, the proverbial “.08” threshold that can decide whether you face charges for drunk driving.

Back in the old days, before breathalyzer technology existed, police had to rely on more subjective ways to decide whether you were DUI: bloodshot eyes, open containers in the car, the smell of alcohol on your breath, slurred speech, whether you could pass field sobriety tests. These techniques were, and are, subject to simple and subjective defenses: you were tired. Your prescription medication was causing side effects. You were distracted. In the end, it’d be your word against the officer’s.

But how do you argue against a breathalyzer? It’s not like you can quibble, “But officer, that looks like a .07 to me.” No, that “.08” or higher reading just stares back at you, like there’s nothing you can do about it.

Or can you?

Although the science behind breathalyzers continues to advance, it is not yet perfect. Studies have demonstrated that under the right circumstances, these measurement devices can produce an inaccurate result. People have tried to take advantage of those circumstances, or to even create them, in a variety of ways. Some never work. Others, however, just might. Let’s take a look at some techniques to confound a breathalyzer, to see whether and how they might help you to unsettle “settled science.”

What won’t work


Before we consider the more plausible was to challenge a breathalyzer test, we’ll dispense with some myths and urban legends that only succeed in making those who try them look foolish:

  • Putting pennies in your mouth. Some people have advocated, and a handful have even tried this idea in the hope that copper from the penny will transfer to their mouths, and that this metallic trace will confuse a breathalyzer. This might succeed in leaving a bad taste, and depending on where that penny has been before you put it under your tongue it might have other undesirable effects. But will it throw off the breathalyzer? No.
  • Using mouthwash, mints chewing gum or other breath fresheners to hide the odor of alcohol or your breath (or in more extreme cases, eating your own underwear or putting your own feces in your mouth). This tactic might make it harder for a police officer to smell what you’ve had to drink, but breathalyzer technology doesn’t detect alcohol the same way that your nose does.

What might work

Although there are no “trick products” that will work to fool a breathalyzer, that does not mean that a breathalyzer’s accuracy cannot be compromised. Let’s take a look at ways with some scientific basis behind them to call into question breathalyzer results.

  • Challenging the mechanical reliability of the breathalyzer. Just like you need to periodically maintain and tune up your car to keep it running in top form, as a precision instrument a breathalyzer must be regularly checked and calibrated and records maintained of when the calibration took place and who did it. If you can show that the breathalyzer used on you was not properly calibrated, this can cast doubt on whether it gave an accurate measurement.
  • Challenging the police officer’s technical competence or legal basis to use the breathalyzer. This can take the form of calling into question the officer’s training in how to operate the device, or whether the officer lacked either the reasonable suspicion to stop your vehicle in the first place or the probable cause to believe you were DUI before having you blow into it.
  • Challenging the officer’s testimony at trial. Often by the time a police officer employs a breathalyzer on you, another officer will be present. But if only one of these officers is present to testify against you, and he or she is not the one who used the breathalyzer, then you might have an argument that you are being denied your right under the Sixth Amendment to the US Constitution to confront your accuser.
  • Introducing environmental conditions that could affect the accuracy of the breathalyzer reading. There are several ways in which the introduction of some external element, such as alcohol in your mouth, might compromise the breathalyzer result. We will go over some of these in more detail below.

How external factors can affect breathalyzer results

Lung capacity of the test subject. The breathalyzer measures alcohol that has been exchanged from your bloodstream into your breath through alveolar air the upper passages of your lungs. It is possible to argue that a person with larger lungs will have less alcohol density in this alveolar air, which might lower the breathalyzer reading for larger individuals.

Breathing patterns. Holding your breath before taking the breathalyzer test, or keeping your mouth closed for at least five minutes before, or even burping might affect the concentration of alcohol in the breath sample because of the presence of small amounts of gastric residue or undigested alcohol in the mouth can result in a reading that is higher than is actually the case.

Chemicals that interfere with the breathalyzer’s function. The penny-in-the-mouth trick may not work, but its premise – that a breathalyzer can be fooled when it picks up something “extra” in the air sample – has some merit. People have claimed false breathalyzer readings in reaction to:

  • Breathing fumes from paint thinners or lacquers.
  • Ingesting over-the-counter products that contain alcohol, such as cough syrups or other cold medications and sleep-aids.
  • Drinking some types of energy drinks, non-alcoholic beverages or carbonated drinks.
  • Eating certain foods such as ripe fruits, hot sauces, breads or dishes prepared with alcohol.
  • Skin products like after-shave, perfume or hand sanitizers.

This list is by no means exhaustive. To give you an idea of how such substances can affect a breathalyzer sample, consider a couple of examples: ketosis, and hand sanitizers.


Breathalyzers detect the presence of alcohol in your breath, but they are not choosy about the kind of alcohol they find. Your alcoholic beverage contains ethanol, but even if you haven’t been drinking your digestive system can produce isopropanol through a process known as “ketosis.” This can happen if you are observing a low-carb diet, have been exercising strenuously, or have diabetes: your body breaks down fat cells to product energy, producing acetone which then breaks down into isopropanol that the breathalyzer picks up.

Note that it is unlikely that ketosis alone would be enough to produce a .08 or higher blood alcohol content reading on a breathalyzer. But if you have drank enough alcohol to put you close to the legal limit, ketosis-derived isopropanol in your system might be just enough to put you past it.

Hand sanitizers


To start with, we are not talking about you swallowing hand sanitizer fluid, or even putting it on your own hands. Rather, if the person administering the breath test to you uses hand sanitizer shortly before doing so, the breathalyzer can read the ethanol in the hand sanitizer. And unlike ketosis-driven results, the hand sanitizer alone can lead to DUI-level breathalyzer readings, even as high as .15 is some cases.

How likely is it that your breathalyzer test will give a bad result?

By now you can see that although a breathalyzer is a precision measuring instrument, it is not infallible. Nor, however, is there such a thing as a “magic bullet” way to beat a breathalyzer test. Even the possibilities that have some scientific basis to them, like ketosis or hand sanitizers, may have little or no effect on your test result.

What is more, police officers and prosecutors are well aware of these possible defenses to a DUI charge, and the better ones train to minimize the risks of a false breathalyzer reading. They will wait for mouth alcohol to dissipate. They will wear gloves. They will take more than one breath sample. They will look for other ways (like field sobriety tests) to back up their decision to arrest you for drunk driving.

Something else to take away from this discussion is that what potential defenses you have against a breathalyzer test depend heavily on the specific facts of your case. Not every defense will apply to every situation. This is where your Memphis criminal defense attorney, in his or her responsibility to zealously represent your interests, must do the investigative work to find out which breathalyzer-related defenses to consider, and how to integrate them into a vigorous and comprehensive defense strategy.

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