If a small amount of alcohol is a sin, then Paul told Timothy to sin when he recommended that he drink "a little wine for thy stomach's sake" in 1 Timothy 5:23. However, we are told not be drunken. Some people should never drink ANY alcohol, because they have no self control. I had one drink of alcohol recently when a neighbor offered it to me. That was my first drink in a long time and will be my last until someone else offers me one. I don't generally buy it.
Yes, I could say, "I don't drink because I'm a Christian." However, I can't back that up with scripture since scripture doesn't say not to drink AT ALL, but simply not to become drunk. It's quite possible to have just one or two drinks and quit. That's all I have during the rare times that I drink alcohol. Well, I did have three glasses of wine at a neighborhood party a while back, but the glass was small and had ice in it.
Everyone should be convinced in his own mind what is God's will for them. We all have our own personal convictions which often cannot be backed up with scripture, and we shouldn't tell everyone that it's a sin just because it is to us.
I knew someone who believed that ANY game that used cards of any kind was a sin. Does that mean that he was right? I had a cousin (or an aunt, I'm not sure), who thought that drinking coffee was a sin. Did that make it a sin for everyone? If you can't back it up with scripture, don't be quick to condemn it for everyone. Yes, if you believe something to be a sin and do it anyway, then YOU have sinned. That doesn't make it a sin for others.