A water bath canner is a large pot designed for preserving high-acid foods, such as fruits, jams, and pickles. It typically comes with a lid and a rack to hold jars in place during the canning process. The canner is filled with water, which is heated to boiling, allowing the jars to be processed safely. Using a water bath canner helps eliminate bacteria and enzymes that can spoil food. The boiling water creates a vacuum seal as it cools, ensuring that the jars are airtight. This method is essential for home canning, making it a popular choice for preserving seasonal produce.