I truly have no idea at all,as I am totally unaware of how to burp!! As a kid when the others were fooling around to be the loudest burper in the group,I was a total outcast,as I could not do it,ever,at all!!!!
I think sometimes when I used to drink fizzy drinks I would burp, especially the beautiful tasting old coke in little bottles! Now I don't touch any of that stuff, its water all the way for me (or a glass of wine)