I just brewed a chai tea brown ale (recipe here) -- which has a target OG of 1.048 -- and ended up with an OG of 1.064. My efficiency for this batch hit 78%, which I presume is higher than the recipe expects (I think most recipes assume 70%).
This means the final ABV will be in the 6-7% range instead of the 4-5% range. I like higher gravity beers, but I wonder if the higher than expected alcohol will put the intended balance of the beer out of whack. In other words, I assume the recipe was formulated such that the final alcohol flavors are milder, allowing, for example, more malt or hop flavors to come through.
To summarize: Will having an alcohol content higher than the recipe calls for unbalance the beer flavors? Should one always strive to hit a recipe's target gravities?