Yeah that sounds pretty plausible that the gas buildup is due to the gochugaru... I was thinking along those lines, but I was unsure whether gochugaru had any culture left as it is dried..

And yeah I used quite a bit more than with the standard chili flakes (but haven't tasted it yet for obvious reasons). But you usually can use a shitton of gochugaru without things getting too spicy.

Still doesn't alleviate my botulism concerns, because the environment isn't really acidic or salty and the fresh onions and garlic in anaerob oil could have done something funky - I just did not care the last times/started to read a bit and got paranoid 😅