A quick lesson on barrels, or more specifically, on the Oak they are made from. You see, there are two basic types of oak tree: red oak and white oak. To the average man, there seems to be little difference, and perhaps while the trees are alive and standing, that would be correct. But once those trees are cut down and used for making barrels, it's a whole other story.
Basically, White Oak is great for holding liquids (and aging them, of course), and Red Oak is great for holding dry goods, like grains. Without being to technical, the difference is in the grain of the tree.
Like all trees, both red and white oaks have long tubes running up them that allow the flow of water to nourish the tree. But in white oaks, these tubes tend to get clogged to the point of preventing water, or any liquid from passing up or through them. This is what makes the wood so perfect for carrying liquids. White Oak is strong and totally waterproof, yet bendable enough to shape. On the other hand, red oaks are more than just good for boxes and crates. Because the wood does allow slight moisture and air to seep through, it is able to keep the dry goods inside of it dry and aerated.
Of course, none of this is new. Cultures have been using oak to hold their food and beverages for nearly a thousand years. In fact, white oak has long been the wood of choice when it comes to aging spirits of all sorts. So by using only white oak for their own barrels and aging, the Chadwicks aren't trying to reinvent the wheel (or I should say the barrel) by any means. They just know not to fix something that isn't broke.