Thirty minutes. According to the inquiry of World.com, the cooking time of vacuum-packed zongzi is related to the size of zongzi. If it is a big raw zongzi, it can be cooked in about 30 minutes, but if it is a cooked zongzi, it only takes 15 minutes to cook. If you are not sure whether it is ripe, you can press it with chopsticks. If it is soft and sticky, it means it is cooked, otherwise it needs to be cooked again.