How can I make sugar-free sangria?
Sangria doesn't have "fizzy pop" of any description in it. 

It has brandy.
That was where it went wrong, long before the sweetener stage.  

Sugar of any description is optional, though personally I'd rather stick my head in a fire than put artificial sweeteners in it, I'd just rather it without anything.  

Rioja - Tempranillo, Garnacha etc
Brandy
Fruit 

You can adjust the sweetness by modifying the fruit mixture if you don't want to add sucrose; though the difference between fructose &amp; sucrose is almost indiscernible 'health'-wise.