The Los Angeles DUI Law Blog

Can a Breathalyzer be Fooled?

In our continuing quest to address every common question a DUI attorney might hear in a bar, we're moving on to ways to manipulate the results of a Breathalyzer test. If you've missed some of the previous questions, we discussed whether you should choose blood or breath and whether it is ever a good idea to outright refuse a blood alcohol content test.

We are not bringing this matter to your attention in order to encourage drunk driving or fiddling with Breathalyzer results. Rather, it is important to know this information because it might prevent you from obtaining a false positive and being wrongly convicted of a DUI.

But as always, the best policy is to find a sober ride.

Urban Legend Falsities

These had to have been devised by drunk people. Some say you can eat garlic. Or drink coffee. Or chew on pennies (ouch!). Truth be told, there are no dietary ways to fool a Breathalyzer. The device measures the amount of alcohol on the breath from your lungs. Food and drink goes to your stomach. The only way food or drink might impact a breath test is if you have consumed alcohol shortly before the Breathalyzer is administered.

Mouth Vomit

What goes down, must come up? That's not exactly it, unless you've downed half a quart of Jose Cuervo. Bad times, my friend. If you've recently vomited, you're going to have some of that alcohol from your stomach floating in your mouth. Gross, right? After upchucking, you should either elect for a blood test or inform the officer, who is required to wait at least fifteen minutes before administering the Breathalyzer.

Breathing Patterns

This is the true revelation. While diet will have little impact on your measured BAC, your rate of breathing can impact a Breathalyzer's results. Think of your breath like a sponge in water. If you take a series of quick breaths, by hyperventilating, you are only getting smaller amounts of alcohol on your breath via your lungs. It's like dipping a sponge in water quickly.

On the other hand, what happens when you leave that sponge to soak in water? The same thing happens when you hold your breath for a long time. The breath sits in your lungs and absorbs more alcohol. You can also obtain an inaccurately high reading by pushing the deepest remnants of breath from the bottom of your lungs. This is why the officer will tell you to "breathe really hard!"

These aren't urban legends. The breathing rate effects were measured in a series of scientific studies, including this one (subscription required), which found deviations from the subjects true blood alcohol content by as much as fifty-five percent, though most of these techniques have far less of an effect.

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