BJCP 7B
A lightly fruity beer with firm, grainy maltiness, interesting toasty and caramel flavors, and showcasing the signature Northern Brewer varietal hop character.
This style is narrowly defined around the prototypical Anchor Steam example. Superficially similar to an American pale or amber ale, yet differs in that the hop flavor/aroma is woody/minty rather than citrusy, malt flavors are toasty and caramelly, the hopping is always assertive, and a warm-fermented lager yeast is used.
Anchor Steam, Southampton Steem Beer, Flying Dog Old Scratch Amber Lager
You can view the complete style details on the BJCP website. The 2008 style guide is obsolete but there is a similar 2015 style that you can view below...
OG: 1.048-1.054
FG: 1.011-1.014
IBU: 30-45
SRM: 10.0-14.0
ABV: 4.5-5.5%