the reason the bags were bloated is because the kim chi was releasing carbon dioxide. you'll notice it might taste a little bit 'sparkly' or carbonated. refrigerate it, stir it every few days, and try not to let it become sentient and mount an insurrection in your fridge.

What causes bloating in packaging?

The reason for bloating packets is limited cooling, which gives rise to bacteria in food. These bacteria thrive on the food in the packet, and produce gas. As the gas cannot go outside of a sealed bag, it continues to accumulate inside, increases the pressure, and bloats up the bag.

What does it mean when food packaging swells up?

Generally, package swelling is caused by carbon dioxide (gas) formation, a by-product of microbial growth. While many organisms may cause spoilage—which is a tactile, visual and olfactory or flavor change that is unacceptable—gas production is generally caused by only three types of organisms (Figure 1).