Chicago DUI lawyer Jennifer Wirth (FindLaw) offers an excellent summary of common myths on how to "beat" a breathalyzer test. A recent entry in Wirth's blog, Frontline DUI, highlights five such myths of avoiding detection for a DUI, such as placing a penny in your mouth, consuming something minty (like gum or an Altoid) or blowing gently on the tube.
Simply stated, none of these methods work if you're drunk.
B.S.-detector web site Snopes.com also debunks the myth of the penny or mint for avoiding detection by a breathalyzer test. The Snopes.com entry includes the following myth, suggesting a way to evade the breathalyzer:
"...the first thing he did was stuff a handful of pennies in his mouth and then spit them out as the officer approached the car. He said a short time later he was given a breathalyzer test because of the copper alloy residue (or whatever), the breathalyzer tester went bonkers and they couldn't get an accurate evaluation."
That just isn't possible.
Another urban legend discussed on Snopes.com is that several states were trying to pressure the makers of Icebreakers gum to discontinue the product because "it would disguise alcoholic content in breathalyzer tests and the readings would come out negative."
That is flat-out false as well.
In fact, nothing placed in the mouth will deter the results of a breathalzyer test. Not mustard, not peanut butter, not Diet Coke, nor anything touted as a wonder-substance for cloaking booze. It's important to keep in mind that breathalyzers measure the chemical reaction between the amount of alcohol on the breath to the contents of a vial in the machine.
In other words, the machine is all science and couldn't care less whether your breath smells like a vodka tonic or a stick of Wrigley's Doublemint.
So although a cop may appreciate fresh breath, don't expect gum or mouthwash (or pennies) to jam a breathalyzer result.