How much ?
Are you talking about 1 drink or a session load?

Are you talking <.18 or no detection. An instrument will detect alcohol or it's metabolites until they are below the detection level of the instrument.

I'm talking about a beer or two, or maybe a couple of jiggers of Bailey's in the morning coffee... say before 11am, would that be detectable in the early evening, say around 7pm?

Breath Alcohol analysis (BrAC) directly correlates with Blood Alcohol Content (BAC). Alcohol is metabolized at about 1 drink per hour (ave. approximation) so, to be safe allow 2 hours per drink. 2 drinks before 11 AM should be completely eliminated from your system before 7 PM

Sorry, 08