A wort chiller is a device used in homebrewing to cool down hot wort quickly after boiling. It typically consists of a coiled copper or stainless steel tube through which cold water flows, allowing heat to transfer from the wort to the water. This rapid cooling helps prevent contamination and allows for a more efficient fermentation process. Using a wort chiller can significantly reduce the time it takes to cool the wort, which is crucial for brewing quality beer. By cooling the wort quickly, brewers can pitch yeast at the optimal temperature, leading to better flavor and aroma in the final product.