I have left off the vinegar largely now, and now only use it if I am having real trouble.

The damage to the vagus nerve which controls peristalsis (movements of the stomach and digestive tract muscles) caused by the parasite infection I had, means that on lying down at night (where I get most of the painful/explosive belching) it can take 6 hours for food to leave my stomach. The belching is caused by fermentation of the foods (particularly if they contain fodmaps).

Normally, food leaves the stomach in 2-4 hours.

The addition of the vinegar just helps reduce this fermentation and aids the digestion, and I find that the food will then leave the stomach and I can finally get some sleep.

Really the only thing that helps me is a strict low-fodmap diet, which reduces the amounts of sugars which can ferment/cause belching.