How to Pass a Breathalyzer: Tips for Accurate Test Results

Updated May 8, 2025

Breathalyzer tests are used to measure the alcohol content in your breath. If you were charged with a DUI, you may be required to install a portable breathalyzer, or Ignition Interlock Device (IID), in your car which will require you to give a breath sample before your car will start. Smart Start, a leading provider of alcohol monitoring devices, uses top of the line technology to provide accurate and timely readings.

So, how do you pass a breathalyzer? Start by understanding how to perform a breathalyzer test correctly and the elements that might impact breathalyzer test results. In this post, we’ll walk you through the process of passing a breathalyzer test, from knowing how they function to helping you stay in compliance.

How Does a Breathalyzer Work?

Breathalyzer tests are designed to measure the amount of alcohol in your breath and then convert it to the Blood Alcohol Content (BAC) value. These tests work by detecting the alcohol molecules present in the breath you exhale, or your Breath Alcohol Content (BrAC). The alcohol concentration in your breath is directly related to the blood alcohol concentration. This is because when you drink alcohol, it gets absorbed into your bloodstream and then evaporates through your breath and other bodily fluids.

Given that breathalyzer calibration is done regularly, this device only takes a few seconds to analyze how much alcohol is in your breath. When you breathe into a breathalyzer device, it measures how much alcohol is in the breath sample. With infrared spectroscopy, a special tool that uses infrared light to measure how it reacts with a certain molecule, the sensor uses light to measure the alcohol content and then a microprocessor takes the sensor’s data and converts it into the Blood Alcohol Content (BAC) value.

Smart Start Ignition Interlock Devices are designed to prevent you from starting your vehicle if your Breath Alcohol Concentration (BrAC) is above a certain limit, which is set by your state authority, such as the Department of Motor Vehicles. The device requires you to blow into it before starting your car, and it will analyze your breath sample to determine your BrAC. To ensure that you pass a breathalyzer test on a Smart Start Ignition Interlock Device, it’s recommended to wait until your BrAC is well below the set point of your Interlock Device before attempting to start your vehicle.

How Long After Drinking Can You Pass a Breathalyzer?

Alcohol metabolism varies from person to person, so there’s no fixed timeframe for passing a breathalyzer after drinking. However, factors such as your weight, gender, and how much you’ve had to drink can all have an impact on this rate. Let’s look at some of the most important ones:

Breath Sample Quality

Providing a proper breath sample is crucial. The first bit of air from your lungs, known as “deep lung air,” is the most accurate for breath testing. It’s important to blow steadily and for the required duration to ensure a reliable reading. Smart Start uses a blow or blow-hum breath pattern to make sure you get the right amount of air on the first try.

• Related post: How Accurate are Breathalyzers?

Alcohol from Food or Hygiene Products

Having any residual alcohol in your mouth, like from mouthwash or breath spray, can impact the results. Certain foods, including sugary foods and carbs, can also create minute amounts of alcohol as your body digests them. To avoid this, we recommend you rinse your mouth with water before taking this alcohol breath test.

• Related post: What Foods Should I Avoid With My Ignition Interlock?

Time and Amount

In general, a breathalyzer can detect alcohol for up to 24 hours, although the so-called “detection window” (the time during which alcohol is detectable on your breath) is shorter for most people.

The detection window is heavily influenced by how much alcohol you’ve had to drink, how quickly you drank it, and how long it’s been since you drank. When you drink faster and drink more, your body takes a longer time to clear it from your system.

• Related post: How Long Can a Breathalyzer Detect Alcohol?

Height, Weight, Age, and Sex

As noted by Medical News Today, height, weight, age, and sex all affect the detection window for a breathalyzer test. Shorter people, slimmer people, older people, and women all feel the effects of alcohol more quickly, and they may also have detectable levels of alcohol for longer.

Smart Start’s goal is to make sure you get accurate and timely results from our breathalyzer devices. Our Ignition Interlocks and portable breathalyzers go through rigorous testing to ensure the best results every time. We want you to be successful in meeting any requirements needed so you can stay in compliance to maintain your driving privileges.

How Do You Pass a Breathalyzer?

If you’re required to take a breathalyzer test, there are several strategies you can employ to ensure accurate results:

1. Wait it Out: If you’ve been drinking, wait a sufficient amount of time before taking the alcohol breath test. This allows your body to metabolize the alcohol and reduce its concentration in your breath. Waiting is the only way to lower your BAC. Common advice like drinking coffee, drinking water, and taking a nap will not lower your BAC or make driving safe, even if you feel less intoxicated.
2. Avoid Mouthwash and Breath Spray: These products can contain alcohol, which could give a high reading, even if you haven’t been drinking alcohol. It’s best to avoid them before taking a breathalyzer test, or choose alcohol-free mouth hygiene products.
3. Rinse Your Mouth: Rinsing your mouth out thoroughly with water before giving a breath sample will help ensure that you get an accurate reading.
4. Follow Instructions: At your Ignition Interlock Device installation appointment, our expert technicians will give you a step by step walkthrough of how to use your device. It may take you a few times to get used to blowing in the device. Blowing too hard or too softly will result in having to take the test again.

How Can You Beat a Breathalyzer Test?

There’s no way to “beat” a breathalyzer test if you’ve been drinking alcohol recently. Smart Start’s Devices are designed to detect alcohol molecules with top of the line technology, and attempts to fool them with your alcohol consumption levels are likely to fail.

Maybe you’ve seen videos on social media or heard tips from a friend claiming to have foolproof strategies for how you can beat a breathalyzer test. However, these claims are ineffective and could even land you in more trouble. Eating certain foods or drinking coffee won’t significantly alter the breathalyzer test results.

In fact, attempting to use your Interlock Device after you’ve been drinking alcohol, or trying to tamper with or defeat the Device in any way, may result in a violation. Consequences vary according to the rules of your program, but they can include paying a fine, having your license suspended, or being required to keep your IID installed for longer.

Why Choose Smart Start as Your Breathalyzer Provider

To understand how to pass a breathalyzer test it’s important to know how our devices and other field sobriety tests work and the factors that influence their results. Smart Start, a leading provider of alcohol monitoring technology for over 30 years, emphasizes accuracy and compliance. If you find yourself in a situation requiring breathalyzer tests, it’s essential to follow proper guidelines to ensure accurate results.

Rinsing your mouth out, waiting a sufficient amount of time, and avoiding alcohol-containing products like mouthwash before the test can also contribute to passing the test successfully. By understanding the science behind breathalyzer tests, you can make informed decisions and get back your driving privileges.