Just as the officer cannot really estimate how much alcohol a person has consumed by smelling his or her breath, so the officer cannot determine when any drinks were consumed. In most cases, an officer cannot even determine with any accuracy what beverage the individual was drinking. After clearly establishing in cross-examination of the officer that from smelling a suspect's breath he cannot determine how much he has had to drink, when he had any drinks, or what the drinks may have been, counsel might then wish to resist asking him just exactly what the importance of breath odor is. Such an officer is a boon to the defense, for that officer is easily shown up before the jury, and the remainder of his or her testimony will be cast into doubt. Many of them can smell somewhat like liquor on the breath.
Many illnesses can cause a type of breath that can be misinterpreted as alcoholic.
A simple case of bad breath undoubtedly has been the true source of many an officer's trigger-quick conclusion that he has smelled the odor of alcohol. And it is well known that belching causes the gaseous odors of the stomach to cling to the throat for a period, often giving off a distinct odor of liquor or greatly magnifying the odorific effect of a single drink. Should the officer deny this, he should be asked why the instructions for the operation of breath analyzing instruments require that the test not be administered for at least 15 minutes after any belching by the subject. Counsel should bear in mind that the detection of alcohol on the drunk driving suspect's breath is the coup de grace in the minds of most police officers. The rest of the observations, including the giving of the field sobriety tests, are pure window dressing.