I just heard a program on XM Sirius Doctor Radio on the subject. Seems it’s either air you swallow from eating to quickly or the normal amount we ordinarily swallow when eating or talking or it’s gas produced by your GI system digestive process. You might consider a breath test to rule out SIBO first since it’s non-invasive. This will hopefully provide a definitive answer as to whether it gas or air. Both can be treated with meds and/or diet change. Good luck. I was recently diagnosed with SIBO but didn’t have burping. My symptoms were all at the other end. You might try keeping a food and symptom diary so you can track what’s occurring when and with what foods. I changed my diet after an antibiotic that cured my SIBO.