Sous vide bags are specially designed plastic bags used for cooking food in a water bath at precise temperatures. They are typically made from durable, heat-resistant materials that can withstand the sous vide cooking process, which often lasts several hours or even days. These bags help to seal in flavors and moisture, ensuring that the food cooks evenly. To use sous vide bags, food is placed inside, and the air is removed to create a vacuum seal. This vacuum sealing prevents water from entering the bag while allowing heat to transfer efficiently. After sealing, the bags are submerged in a water bath, where the food cooks to the desired doneness.