In Florida the charge of DUI has some simple elements that the state must prove for you to be found guilty. First that you consumed alcohol or controlled substances. Second that you were operating a motor vehicle on the roads of the State of Florida. Third that your normal faculties are impaired.
If you have one drink, you have satisfied the first element of proof required for the state to convict you. Even one drink qualifies for “having consumed alcohol” or controlled substances. If you are driving on the road, you have also met the second element of DUI, that is operating a motor vehicle on the roads of the State of Florida.
The third element is interesting because the question of “normal faculties impaired” can be one of the police officers opinion, and does not require the evidence of a breath test. Surprisingly the law does not require a breath test for prosecution of DUI. The third element can be proven by the officers testimony that “ in his opinion” you were impaired. This is normally proven by physical observations such as slurred speech, red bloodshot eyes, the smell of alcohol on your breath, poor balance, difficulty producing your license and registration, leaning on the car, and what most people are familiar with the road side field sobriety tasks. So even if there is no breath test, or you refuse a breath test, the police can still provide their opinion that you were impaired based upon their observations.
Moral of this story, it is better not to have even one drink and get behind the wheel of a motor vehicle.