Mouth Contaminants Explained

“I haven’t had anything to drink, but my interlock has detected alcohol!”

We’ve heard this comment hundreds of times, and we can relate to it!

Alcohol isn’t limited to beer, wine & spirits. It’s present in a lot of everyday substances. From bread and pizza to mouthwash, fermented products like kombutcha, hand sanitiser and even perfume. Alcohol can be found in a lot of unexpected places.

The presence of alcohol in unlikely places isn’t a recent discovery. Back in the 1920s, the American Chemical Society ran a set of experiments to report on The Alcohol Content of Bread.

There isn’t a complete list of substances that contain alcohol so it’s important you take precautions to prevent causing a mouth contaminant reading.

If you’ve had anything to eat, drink, smoke, or chew, have a drink or water and wait at least two minutes before you blow into your interlock.

This pause, along with the water, will allow any residual alcohol lingering in your mouth (hence the term ‘mouth contaminant’) to dissipate.

The lists below don't cover all mouth contaminants but it will help give you some idea of what to look out for.

Yeast Products
Probably the most common fail (apart from true alcohol fails) somes from yeast products in the mouth. When combined with sugar, yeast creates alcohol and CO2 byproducts. It's important to take care before testing if you've consumed yeast products, including:

• Bread
• Donuts
• Pizza
• Hamburgers
• Sandwiches
• Other baked goods

Vanilla Products
Vanilla extract is high in alcohol content, it can be up to 40% alcohol. Items with vanilla in them which may cause alcohol readings are:

• Ice cream
• Coffee syrups and creamers
• Vanilla flavoured soft drinks
• Some baked goods

Cosmetics / Toiletries
Products that we use to get ready when we wake up have the ability to ruin your morning if you're not careful. This is because some of these products contain alcohol, including:

• Hairspray
• Cough drops / syrup
• Sleep aids
• Lip gloss
• Perfume

Other Items
There are too many different items to list that can cause issues. As we've mentioned, if you're using an interlock take extra care to wait a couple of minutes and drink a mouthful or two of water if you've had anything to eat, drink, smoke, or chew. There are a few final items that are worth listing because they come up often:

• Hand sanitiser
• Petrol
• Strong smelling chemicals
• Energy drinks
• Vapes 

Clearing Contaminants
We'll say it one final time 😊 It is VERY important that you take the time necessary to remove potential mouth contaminants from your mouth or lungs prior to blowing into your interlock. Any fail could affect your interlock programme which could result in additional fees. Before every test (expecially if you've had something to eat, drink, smoke, or chew) we recomment that clients follow these two simple steps to eliminate contaminants:

1. Rinse your mouth with water: swishing with water helps to break up food particles in the mouth
2. Take a few deep breaths: deep breaths in and out will help remove any alcohol vapours present in your lungs
3. If in doubt, wait a few minutes ⌛

If you've been drinking alcohol and unsure if it's still in your system
It’s important to note that ingested alcohol (alcohol from beer, wine, spirits) can be present in your system for a long time. If you’ve had anything to drink in the 24 hours prior to taking a test, we recommend you first test yourself with a personal breathalyser to ensure you don’t blow an unintentional violation.