Barrels are an important factor when it comes to blending. Specifically, barrels made from French oak  vs. old / neutral French oak. 

Neutral barrels allow the wine to display more of the varietal characteristics, while new French oak barrels add vanilla, smoky, chocolate, espresso and oak flavors to the wine.  New barrels also add weight to the palate, sometimes giving the wine an almost chewy aspect.

Using oak barrels is a way of adding complexity to the wine, through added oak components.  However, these components are not the only thing we are after in using the barrels. The barrels also allow very small amounts air to pass through the air-stave interface.  This oxygen is very important for the wine aging process.  The oxygen allows for softening of the tannins by complexing or binding of tannins with other tannins to make large protein compounds. This makes the tannins softer and more stable in the wine.

 As the blender for your own wines, your audience is going to be different then ours. When we make our blends we are looking to maintain a consistent style, which our customers enjoy. Our decisions attempt to produce the most constituent and highest quality example of the particular wine in question.