I recently made a classic stout which has some serious flaws - but unfortunately I can't quite decide what is wrong. I entered the stout in a contest to get some additional feedback. Judge #1 described it as vegetal, and judge #2 marked it as astringent, estery, musty, solvent, sour/acidic, and yeasty (but not vegetal). It was a simple recipe: 9 lbs 2-row, .75 lbs roasted barley, and 1 lb flaked barley. I used 2 oz cascade hops for boiling. Yeast was Wyeast London Ale (3056).
I guess it could be an infection - but it doesn't really taste that way. It isn't hazy, and the carbonation is appropriate (not gushing, not flat).
Any thoughts about what could be the problem?