Harrisonburg DWI DUI Lawyer Bob Keefer:  The smell of alcohol on a person's breath does not always mean the person consumed alcohol. 

From Defending DUIs in Washington, 3rd:


At this point it should be noted that the presence of alcohol in an individual’s breath does not mean that the individual has actually consumed alcohol. “[S]everal investigators have confirmed the presence of ethanol in samples of blood and breath from healthy abstaining subjects.”[1]  The concentrations observed display “large inter-individual variations.”[2]  Although the origins of endogenous ethanol and its biological significance are not fully understood,[3] one mechanism for the production of alcohol in the body is well documented: fermentation of carbohydrates in the gut.[4]  Candida Albicans, a yeast, “is one of the normal flora in the human gastrointestinal tract.”[5]  Under the right conditions, C. Albicans ferments carbohydrates into ethanol in the gut.[6]  The effect can be severe in individuals with certain gastrointestinal disorders, even causing noticeable intoxication.[7]  This phenomenon is known as “autobrewery syndrome.”[8]  It can result in breath alcohol concentrations as high as .25 g/210L.[9]  Given the significance of these effects, both “toxicologist and forensic scientist should be aware of the significance of the syndrome.”[10]  “All those concerned with alcohol intoxication…must bear this syndrome in mind and should consider mycological examination as well as sensitive biochemical analysis.”[11]