I went down this rabbit hole last year after buying a carbonator. Rather than mixing a bunch of oils together, I bought my flavors from Bakto Flavors (based in NJ, USA) which is founded by Dr. Daphna Havkin Frenkel who did her research in food sciences and biotechnology, focusing on vanilla. The cola flavor is really good, and I add acetic acid (Vitamin C) + electrolytes to it. If I'm feeling it, I'll add in vanilla, cherry, or lime flavors to it.
Sad to hear she passed away recently this month.
Highly recommend Bakto's natural flavors.
Are there any reasonably priced water carbonation systems that aren't sodastream adjacent?
I know there are hacks for the older sodastreams where you can buy a large tank from a foodgas company, but what I really want is a machine in my house that I can bring a cup to and fill with soda without it costing me ~$1,000.
> acetic acid (Vitamin C)
ascorbic acid!