Once the flavor profile, materials, and assembly technique for a bar have been selected, the logistics of assembling the bars must be determined. Generally, it is sensible to have the firmer or crisper layers on the bottom of the finished bar. In addition, flavor, color, and mouthfeel may influence the order of the layers. Whenever possible, it is preferable to deposit one layer directly onto another one, as opposed to pouring them separately and stacking them after each has set. Pouring layers directly onto one another provides better adhesion between the layers and a more uniform bar. Regardless of the order in which the strata will ultimately appear, the confectioner must consider the order in which the centers may be successfully assembled. If, for instance, a caramel layer is to be combined with a heat-sensitive layer such as gianduja, the caramel must be deposited and cooled before the gianduja can be applied. That makes it necessary to sometimes assemble layers out of order or entirely upside down. Ultimately, this makes no difference, as once cooled, the slab can be inverted to create the desired effect.