its quite possible you have very few unfermentable sugars in the original wort, so it fermented very completely, leaving you with a dry beer.
Beer, just like wine, can be described as Sweet or Dry, malty or hoppy, balanced, etc.
I'm not convinced this is any kind of 'off flavor'.
What was the OG ,and what was the FG at bottling?
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10