I'm making America's Test Kitchen's fermented jalapeno recipe for the first time. Here's a pay-walled link.
The general idea is you pack halved-through-the-stem jalapenos, shallots, garlic and lime zest into a quart jar, make a high-salinity brine, pour it over (tight packing keeps the peppers submerged), then ferment at 50-70F for 10-14 days. Refrigerate for up to five months. This works fine, but I noticed when I tried the first batch that there were a few air bubbles trapped by the halved jalapenos. Is that a problem? I know I need to keep the peppers submerged or they will start to rot, but are a few small air bubbles trapped by the food okay? I can't easily fix the air bubbles through any method I've imagined. I can't shake the jar. That would just distribute the headspace. I might try packing them concave-side-up next time, but that makes it tricky to pack them tightly.
I've consulted a few other recipes like this one that don't mention air being a problem, and I've seen a few other passing references on the web to air bubbles being okay in fermented food as long as the food isn't producing gas from a bacterial process. But, I'm new to this, and I don't want to accidentally give myself some kind of food poisoning.