Personal Health
One standard drink can raise blood alcohol concentration to levels known to impair coordination and reaction time within 30 minutes.
One standard drink will always result in a BAC under 0.02% for people under 140 lb, so any impairment is negligible.
Alcohol must be present for at least 2 hours before it causes any measurable impairment, so 30 minutes is too soon to worry.
Eating food after the drink makes BAC zero immediately, so driving is safe after eating.