#1 Way to do this: read the sign over the stack in the store
#2 Color: Red Oak is red, with some white streaks. White Oak has a yellowish grey tinge to it, with white streaks.
#3 White Oak is heavier
#4 Now that we have all of the “DUH” answer out of the way, here is a neat trick.
Find a smoker. They can blow smoke into the end grain of White Oak and it will travel down the veins and arteries of the wood. I have had it travel up to 3 feet through White Oak. Red Oak, the veins and arteries tend to be more clogged and I’ve never had it travel more than 5 inches. So when you find the squirrely piece that really could be a little too heavy be Red or maybe too dark to be White, find a smoker. This is a sure fire way to tell.