I'm trying to figure out what gomme is.
Aren't you a bartender? Gomme sugar syrup.
(sorry, can't be arsed to figure out how to do the e acute at the end of gomme)
Try it, you'll like it.
I looked it up. I'm quite familiar with sugar syrup, and I use it all the time. But gomme, at least according to wiki, contains gum arabic, which I am unfamiliar with.
The sugar syrup I use is just sugar and water.