In by-gone days these were referred to as strong ale, stingo, Burton ales, old ales and Scotch ales. Such diversity shrouds the origin of this style in mystery. First appearing centuries ago in small house-breweries, a brewer's motivation for producing these strong ales was probably a combination of preservation and bragging rights. They counted on these statuesque beers to increase their standing with the brewery's patrons, and of equal importance, cellar over a considerable period of time. Use of the modern name - Barley wine, can be attributed to the high alcohol, which rivals that of wine, along with the practice of maturing in wood.
Fermentation produces both products, but no other connection with wine exists.
Achieving a thorough fermentation presents the greatest challenge in making this style because ale yeasts have limited tolerance for high alcohol. Thus, the yeast goes dormant and falls to the bottom of the fermentation vessel without completing its job. Brewers overcame this by using a combination of two methods. In a more modern practice the brewer might take a shortcut by a late pitching of alcohol tolerant yeast strains, such as those used in champagne. Higher levels are typical and breweries bottle them accordingly.