We intentionally ferment fresh Kimchi in room temp for fast PH dropping. PH of fresh Kimchi normally starts from ph 5, and then they drop to 4.2 in one or two days in room temperature depending on season. When PH is under 4.2, any harmful bacterial hardly grows on our Kimchi. Acidic bacteria protects Kimchi from bad pathogen and bacteria. As we normally send fresh Kimchi to you, it keeps fermenting on the way to you. But during hot summer time, it can be very active with creating more gas due to warm temp causing the pouch with Kimchi in bursting open and the lid of the glass jars popped off as the gas push it over. I highly recommend to add Ice gel and thermal packaging material during summer season. For people living in South Island, I highly recommend to purchase these extra packaging all the time as it takes 3 over nights.