A barley wine typically reaches an alcohol strength of 8 to 12% by volume and is brewed from specific gravities as high as 1.120. Use of the word wine is due to its alcoholic strength similar to a wine; but since it is made from grain rather than fruit, it is a beer.
There are two primary styles of barley wine: the American which tends to be more hoppy and bitter with colors ranging from amber to light brown and the English style which tends to be less bitter and may have little hop flavor, with more variety in color ranging from red-gold to opaque black. Until the introduction of an amber-colored barley wine under the name Gold Label by the Sheffield brewery Tennant's in 1951 (later brewed by Whitbread), British barley wines were always dark in color.
Michael Jackson referred to a barley wine by Smithwick's thus: "This is very distinctive, with an earthy hoppiness, a wineyness, lots of fruit and toffee flavours." He also noted that its original gravity is 1.062.
Martyn Cornell has been quoted as saying "no historically meaningful difference exists between barley wines and old ales". He later clarified, "I don’t believe there is actually any such meaningful style as 'barley wine'".
Barley wines are sometimes labeled with a production date, as they are intended to be aged, sometimes extensively.