title_body: Why is chaptalization illegal?
upvoted_answer: Chaptilization is the addition of sugar, mostly cane sugar but could be other sugars like beet or corn. 
  
  Chaptilization is only illegal in several countries and one state in the USA. Here is the list Australia, Austria, Germany (for high quality wines), Italy and South Africa. 
  
  Chaptilization is permitted in only certain areas of France. Those are Bordeaux, Burgundy, Alsace and Champagne. There is no need in warmer climates where the grapes get higher brix (sugar levels)
  
  No it's not dangerous to consume chaptilized wine. The main reason is to bring a wine up to around 11-12 potential alcohol so the wine is stable and in balance. Cool climate places like Germany and France routinely have under ripe grapes and sometimes need a little help getting across the finish line. 
  
  If done in moderation, all the sugar added will be consumed by yeast and turned into alcohol. I suppose you could go crazy and make a wine with so much sugar it wouldn't finish fermenting. Some people swear they can tell when a wine has added sugar, but as far as I know, nobody can really tell by tasting if done in moderation.
  
  Why is it banned in the warmer places like California, Australia and South Africa? There simply isn't a need. The grapes get ripe on their own. 
  
  There is one big loophole to get around this, you can use grape juice concentrate to give you an added boost if you are in bad (cool) year. But for the most part if you are looking at a crappy and cool year, say in California, you might just buy grapes from a warmer location and do some blending.
  
  Chaptilization on Wikipedia