About This Answer
A practitioner who has kept the fifth precept strictly for over ten years asks whether drinking alcohol before encountering the Dhamma will harm future rebirths. Ajahn Dtun replies that breaking any precept harms oneself and brings consequences, and the results of actions do not disappear; it is as if they are recorded.
However, since the drinking stopped long ago and only good actions have been done since, the goodness leads the way more than the negative actions. At the breaking up of the body, he says, one would normally experience the results of good kamma first.