The ancient Roman kitchen was known for its advanced culinary techniques and innovative cooking methods. One of the appliances commonly used in Roman kitchens was a built-in steam oven. These ovens, known as 'caldaria', were made of brick or stone and had a hollow cavity where water was heated to produce steam. The steam created a moist cooking environment, allowing the Romans to cook a variety of dishes with precision and flavor. The caldaria were used for steaming vegetables, fish, and even bread. The Romans believed that steaming preserved the natural flavors and nutrients of the food, making it a popular cooking method in their kitchens.