Precoating centers performs two vital roles: it makes the centers easier to handle, and it prolongs the shelf life of the finished product. Precoating a slab is also known as “bottoming,” because it is always the bottom of the piece that is coated. Precoated centers are easier to handle because the bottom coat prevents a soft center such as ganache from sticking to the dipping fork, and it helps the center hold its shape. In addition, the product’s shelf life is improved because the bottom coat prevents the center from settling through the chocolate before it sets, leaving a vector for moisture migration and allowing for exposure to oxygen. Moisture migration can cause drying, crystallization, and spoilage. Exposure to oxygen contributes to rancidity.