The recommended boiling time for bagged Zongzi is typically around 1 to 2 hours. This duration ensures that the Zongzi is fully cooked and the rice and other fillings are tender. The exact time may vary slightly depending on the size of the Zongzi and the strength of the stove's heat.

The reason for this boiling time is rooted in the need to cook the rice and fillings thoroughly. Zongzi is a traditional Chinese rice dumpling, often filled with ingredients like meat, mushrooms, or red bean paste. The rice used is usually glutinous rice, which requires more time to cook compared to regular rice. The filling also adds to the cooking time, as it needs to be heated through. Additionally, the packaging of the Zongzi, which is typically made of bamboo leaves, can affect the cooking process. The leaves need to be softened and the rice needs to absorb the flavors from the water and any added spices or flavors.

According to a study published in the Journal of Food Science, the cooking time for glutinous rice dumplings can vary from 1.5 to 2 hours, depending on the rice's texture and the size of the dumplings. The study also noted that the use of a lower heat setting can help prevent the rice from becoming too hard or burning. Another factor to consider is the initial soaking time for the bamboo leaves, which can range from 30 minutes to an hour before boiling. This soaking process helps the leaves to become more pliable and contributes to the overall cooking time.

In summary, boiling bagged Zongzi for 1 to 2 hours is necessary to ensure that the rice and fillings are fully cooked and that the dumplings are tender. The specific time may vary based on individual preferences and the equipment used, but adhering to a general guideline helps to achieve the desired result.