In the early years of their existence, Baptists were no different than others in their attitude toward alcohol. In fact one of the early distillers of whiskey in Kentucky was a Baptist preacher named Elijah Craig, who established a distillery in 1789. Craig is credited with having developed Kentucky Bourbon, although that is probably not correct inasmuch as his distillery was in Scott County and Kentucky Bourbon took its name from Bourbon County, Kentucky.
Like Izadaari said, the negative attitude toward alcoholic beverages began in the 1800’s. It probably originated on the frontier where there where drunkenness seems to have been more prevalent. Certainly it was a problem among the Indians. The approach of the Baptists, and others as well, was that this social problem would not exist if no one drank. How to prevent drinking? Prohibition, of course.
A significant majority of Baptist churches today have what they call a church covenant. Most of them are virtually identical, and were taken from a document written in New Hampshire arount 1833. Each church adopts it independently of any other church, but most of them do adopt it. I have highlighted the “alcohol” clause.
As one who has been a Southern Baptist all my life, I can confidently say that the majority of Baptists don’t drink. However, a significant number do. In my church I would guess that would be about 75% total abstainers and 25% who drink.