I abused alcohol in my youth. I think that I did that because, although my parents enjoyed alcohol in moderation (I never ever saw them abuse it), they did not introduce me to it. Instead, my friends did. Not good. And, as long as I am in a confessional mood, I experimented with marijuana in my youth, as well.
But fortunately, and by the grace of God, I grew up. I think that I was maybe 23 when I decided to never abuse alcohol (or use marijuana) again. And I never have since. Not once.
And through it all, I was and am a Christian. I became a Christian when I was a child...ten, I think. So, I was a Christian while I was abusing alcohol and smoking dope.
And that's just it...Christians aren't perfect. Merely saved and forgiven. We are, like everyone, born into sin. If we become saved, truly saved, then it is our goal to become more like Christ with each passing day. It is, by definition, not achievable but it is a goal nonetheless. Those who are truly saved work toward it all the while knowing that they will never get there. There will be setbacks along the way...we will backslide from time to time. But loving Christ (because He loved us first) means that we will not stop trying to follow His example in all things.
This is one of the more difficult things for non-believers to come to grips with. They mistakenly believe that we think that because we are Christians we are perfect. They seem to relish any opportunity to call Christians hypocrites. And...some of us are. But I choose to believe that the hypocritical Christians are those who just need to grow a bit more in the right direction.
At any rate...I know what sin is because I am a sinner. But I also know that the alcohol that I enjoy (not abuse) now, the act of consuming it...savoring the experience...is not a sin. There is still sin in my life and there always will be but drinking in small amounts, something considerably short of intoxication, isn't sin.
So there it is.