What is Residual Mouth Alcohol?


In a law enforcement training manual that is recognized by police officers across the United States, entitled DWI Detection and Standardized Field Sobriety Testing (HS 178 R8/06), which is endorsed by the U.S. Department of Transportation and the National Highway Traffic Safety Administration (NHTSA), provides this definition and warning to police officers about Residual Mouth Alcohol, when using Roadside Preliminary Breath Testing (PBTs) devices:

“Residual Mouth Alcohol:  After a person takes a drink, some of the alcohol will remain in the mouth tissues. If the person exhales soon after drinking, the breath sample will pick up some of this left-over mouth alcohol. In this case, the breath sample will contain an additional amount of alcohol and the test result will be higher than the true BAC.”

“It takes approximately 15 minutes for the residual mouth alcohol to evaporate from the mouth.”

“The only sure way to eliminate this factor is to make sure the suspect does not take any alcohol for at least 15 to 20 minutes before conducting a breath test. Remember, too, that most mouthwashes, breath sprays, cough syrups, etc., contain alcohol and will produce residual mouth alcohol. Therefore, it is always best not to permit the suspect to put anything in their mouth for at least 15-20 minutes prior to testing.”



Residual Mouth Alcohol in Roadside Breath Testing


Roadside breathalyzers have been used for decades by law enforcement officers to aid in the arrest decision making process, when determining if someone is under the influence of alcohol, to the extent that they are less-safe to be driving or in excess of a statutory Per-Se legal limit. Throughout the United States, the statutory Per-Se limit is .080 grams. However, despite documented training to law enforcement officers on how residual mouth alcohol can contaminate breath samples when using these handheld devices, this limitation is sometimes ignored.  Ignoring this extremely important limitation with roadside breath testing, could lead to innocent people being wrongly arrested for DUI.

Despite the fact that police officers often also use a battery of other field sobriety tests and observations of physical manifestations of impairment, the one thing they put the most weight on when making the arrest decision is the handheld breathalyzer or PBT (Preliminary Breath Test), because it’s the only tool they use that gives a direct digital reading of what the person’s approximate blood alcohol level is. To support this contention, please refer to NHTSA’s (National Highway Traffic Safety Administration) DUI Detection and Standardized Field Sobriety Testing Student Manual HS 178 R8/06 Page VII-7 where it says ”The PBT result is an important factor because it provides direct indication of alcohol impairment.”

For instance, if a person passes all other field sobriety tests the officer asks them to perform, but blows over .080 on the handheld breathalyzer, they will be arrested. On the other hand, if a person fails some of the other field sobriety tests, but passes the handheld breathalyzer, they are most likely going to be released from the scene without arrest, unless there is a suspicion of the person using drugs or they have been deemed a less-safe driver from the amount of alcohol they have consumed, even though it’s below the Per-se limit.

The purpose of our product, “Breathalyzer Equalizer” is to help responsible drivers that are not intoxicated, but have recently consumed an alcoholic beverage, used mouthwash or breath freshener sprays, asthma inhaler, etc., avoid being arrested for DUI on the mere presence of residual mouth alcohol in their oral cavity. Recent consumption (Within 15-20 minutes of test) of an alcoholic beverage or use of some of the products listed above, could produce an erroneously high breath test result on a roadside breathalyzer, potentially leading to them being wrongly arrested for DUI or detained unnecessarily at roadside.

Law enforcement training manuals and the manufacturer’s operator manuals for these roadside testing devices, clearly warns police officers about the limitations of residual mouth alcohol and directs them not to use these devices on drinking individuals, if they have consumed any alcohol within 15-20 minutes prior to testing.


Here are Direct Quotes from Police Officers’ Operator Training/Manuals

from Some of the Most Popular Roadside Breathalyzers Used in Law Enforcement Today:

Source: Online Certified Training for the Alco-Sensor FST.

“No test should be administered within 15 minutes of consuming alcohol.”


Running a Direct Test


“Before running a test, there are some pre-testing issues to consider.”Wait 15 minutes before testing individuals suspected of recently consuming alcohol. Eliminate the possibility of contamination from mouth alcohol.”
“Mouth alcohol is alcohol that remains in the mouth cavity after a recent drink. The presence of alcohol in the mouth can result in a false positive. Mouth alcohol dissipates completely within 15 minutes. By waiting 15 minutes before testing individuals suspected of recently consuming alcohol, the possibility of a false positive due to mouth alcohol will be eliminated.”

Source: Alco-Sensor III Operator’s Manual (Page 4)


“A Recent drink of an alcoholic beverage, a dose of medication containing alcohol or regurgitation could introduce mouth alcohol to the breath sample thus causing an exaggerated reading. A 15-20 minute deprivation period prior to testing will insure mouth alcohol has not influenced the breath alcohol reading.”

Source: Alco-Sensor IV Operator’s Manual (Page 10)


“Observing a 15 minute deprivation period prior to testing, where no substance is introduced into the mouth, will ensure the elimination of “Mouth Alcohol”.  ”When using the Alco-sensor IV to administer an evidential test without a preliminary test, it is recommended the subject to be kept under observation for a period of time dictated by the agency’s testing protocol, usually 15-20 minutes prior to testing.  This ensures complete dissipation of any residual alcohol that may have been in the subject’s oral or nasal cavity or alimentary tract.”


In conclusion, residual mouth alcohol is a real problem with roadside breath testing, which may result in innocent people being arrested for DUI, when they shouldn’t be. Drunk driving is a serious problem and should have no tolerance in our society, but innocent people should not pay the price of being arrested for DUI, because of the presence of mouth alcohol that may have elevated their BAC erroneously. This is why our product “Breathalyzer Equalizer” will only help improve the accuracy in roadside breath testing, which will assist law enforcement in arresting and punishing those actually guilty of DUI.




The Breathalyzer Equalizer is a revolutionary product that was professionally formulated by McCoy Moretz, MD FACS, to deal forthrightly with a problem affecting citizens throughout the country, called Residual Mouth Alcohol.  Mouth Alcohol has nothing to do with the true Blood Alcohol Concentration (BAC) and can produce an errant reading on handheld roadside breath testing devices, used by law enforcement. The Breathalyzer Equalizer is made of all natural food grade ingredients, which absorbs only the Residual Mouth Alcohol that can produce a false positive on these roadside breath testing devices, used by law enforcement in the field.