The best pot for double-boiling in water is a combination of stainless steel and clay. Stainless steel pots are ideal for their durability, non-reactive nature, and even heat distribution, making them suitable for maintaining the temperature of the water throughout the cooking process. On the other hand, clay pots offer excellent heat retention and are known for their ability to enhance the flavor of the food due to their porous nature. A clay pot, when used in double-boiling, can help to prevent the water from boiling over and can also contribute to a more delicate and nuanced flavor profile. According to a study published in the Journal of Food Science, clay pots can retain heat better than stainless steel pots, leading to more efficient cooking and better flavor retention.