Conching is an important step in the process used to turn cacao beans into chocolate. Without conching, the resulting chocolate will be gritty, lacking the smooth, even texture which people associate with chocolate. After conching, the chocolate can be tempered and then poured into molds to make bars, truffles, and a variety of other chocolate products. Most people do not conch their chocolate at home, unless they are making chocolate from scratch, as the process is laborious and time consuming.

Before the development of conching, chocolate was rarely sold in bar form, because chocolate bars were gritty, with sharp particles of material which made the product taste rather unpleasant. Instead, people drank their chocolate; for a time, chocolate was a very exclusive drink enjoyed only by royalty and the upper classes. In the late 1800s, a chocolate producer developed the conching technique, which involves grinding the chocolate for hours on end, polishing the particles in the chocolate to create a smooth end product. The process is named for the containers originally used for conching, which resembled shells; concha means “shell” in Spanish.

Today, conching is performed in huge industrial machines which can run for up to 96 hours, and sometimes even longer. The length of time required for conching varies, depending on the origin of the chocolate being conched, and any ingredients conched with the chocolate. The chocolate is kept warm and liquid through the friction created by the conching machine, which grinds the chocolate against a hard surface using rollers.

It is possible to construct a conche at home. People who enjoy mixing and creating their own chocolate may also use special attachments for food processors and blenders for conching. For home cooks, conching can be a challenge, because it generates a great deal of heat. Most home appliances cannot withstand the conching process, which requires them to run for hours or days at a low speed.

Industrial manufacturers of chocolate often show off their conches during factory tours, because these machines are incredibly large and quite impressive to see. Conching is designed to process huge batches of chocolate, and many companies have rows and rows of conches to accommodate the demand for their chocolate. The conching room smells intensely of chocolate, as you might imagine, and it's also quite warm and noisy, thanks to the running machines which pulverize the chocolate to the desired texture.