The primary function of roasting is to develop chocolate flavor. Fermented, unroasted cocoa beans exhibit little or no chocolate aroma but contain the precursors to create chocolate flavor. Just as coffee may be roasted to varying degrees for different results, cocoa beans may also be roasted to different temperatures for specific flavor profiles, depending on the desired outcome and the beans used. Roasting may be performed at different points in manufacturing. There are three main methods of roasting in common use: whole-bean roasting, nib roasting, and liquor roasting. Each method has its unique advantages and challenges, but excellent results can be obtained from any of these methods. In all cases, the object is to roast the beans to develop optimal flavor without roasting them too much, which can overshadow flavor nuances. Lower-roast chocolates often exhibit a reddish color, while darker-roast chocolates are a deeper brown. In addition to developing flavor, roasting removes most of the remaining moisture from the beans, making them more friable for further processing. When roasting is completed, the cacao has developed its chocolate flavor but still has a decidedly sour aroma due to the volatile acids that are by-products of fermentation. These acids are not removed until near the end of processing, during conching. Due to naturally occurring differences between varieties and batches of beans, it is desirable to roast varieties of beans independently of one another in order to ensure optimal flavor development. Only then are the varieties of beans blended.