McFarlane's Reserve 4 Grain is a bourbon, a style of American whiskey typically made with a mash bill led by corn and matured in new charred oak barrels. For new drinkers, bourbon is often associated with a fuller, sweeter profile than many other whiskey styles.
The "4 Grain" name suggests a recipe using four different grains rather than the more common two or three. That can indicate a broader grain character, but specific flavors depend on the producer's recipe and maturation, so this bottle is best approached as a bourbon with potentially layered grain influence.