While breath alcohol testing is much less invasive than a blood test, it is highly susceptible to foreign contaminants.

Alfonso Gambone
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A Philadelphia criminal defense attorney representing accused persons throughout Pennsylvania and New Jersey.

Our criminal defense law firm handles a large volume of drunk driving cases for clients in Pennsylvania and New Jersey. A critical issue in these matters is frequently blood alcohol content or concentration (BAC). In Pennsylvania and New Jersey the severity of a DUI/DWI is based on the level at which a person’s BAC exceeds the legal limit of .08. Keep in mind that in both states the prosecution doesn’t necessarily need a specific BAC to convict someone of driving under the influence as both jurisdictions maintain a general impairment section of their DUI/DWI code.

Blood vs. Breath Testing Accuracy

In those cases which use BAC, the prosecution will present it in the form of a blood test or a breathalyzer (Alco test—New Jersey). Blood evidence is much more precise than the results from a breathalyzer. There have, however, been a number of recent challenges over the admissibility of blood evidence and I have written a number of articles on this issue.

While breath alcohol testing is much less invasive than a blood test, it is highly susceptible to foreign contaminants. Keep in mind that even a blood test can have contamination issues if the proper cleansing agent isn’t used prior to drawing the blood (iodine base solution) or if it isn’t properly stored. Unlike a blood test, breath alcohol content is measured by taking the alcohol vapor exhaled from the lungs and multiplying that amount by a factor known as the “partition ratio”. This test is designed to provide law enforcement with an estimated blood alcohol content but makes various assumptions to determine BAC.

Chemical Breath Testing Assumptions

These assumptions however do not take into account other contaminants which may negatively affect a breath test.  If you are charged with a DUI in Pennsylvania or New Jersey it’s important to consider that any of the following products may have caused an increased BAC which didn’t accurately reflect your level of intoxication at the time of your arrest. If you consumed any of these products it’s important that you bring it to your criminal defense lawyer’s attention so that he may consider retaining an expert witness prior to trial that can help establish reasonable doubt in the mind of a judge or jury.

Yeast Products

Yeast, when combined with sugar (glucose) creates alcohol and CO2 byproducts. Yeast inside your mouth can “ferment” enough to cause an issue with a breathalyzer test. Consuming any of the following items with alcohol will raise the alcohol content in your mouth and therefore negatively affect breathalyzer results. These products include:


  • Loaf bread
  • Donuts
  • Pizza dough
  • Hamburger/hot dog buns
  • Other baked goods


Vanilla Products

Vanilla extract is high in alcohol content. USDA guidelines require that vanilla extract hold between 35-40% alcohol, which is the equivalent of 70 proof liquor. These items may elevate your BAC level and include

  • ice cream,
  • coffee creamers,
  • vanilla flavored soda, and
  • baked goods


Cosmetics/Toiletries/Other Products

During the course of our day we obviously use many personal products but it’s important to keep in mind that simply breathing in fumes from any of the following items can negatively affect a breathalyzer test. These items include:


  • Toothpaste
  • Hairspray
  • Cough drops/syrup
  • Sleeping aids
  • Lipstick/gloss/lip balm
  • Hand sanitizer
  • Energy drinks
  • Gasoline


It’s important to keep in mind that if you plan on driving after consuming alcohol that you consider drinking a glass of water prior to getting into your vehicle. In addition, I also recommend taking a few deep breaths in and out to remove any additional chemical vapors present in your lungs. These simple steps can greatly reduce the chances that a breathalyzer will create a false positive result. While there is a lot that your attorney can do to challenge a false positive, it’s obviously much better and less expensive to consider these simple steps to reduce the chance that you are wrongly arrested for DUI. For more information on drunk driving in Pennsylvania and New Jersey I encourage you to keep reading my blog and visit my free downloads section.

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