I make a bunch of candi syrup. Burnt sugar flavor definitely comes through in the finished product. There are a couple things going on when you make caramel to keep in mind. PH affects dehydration reactions. As your sugar darkens, the pH falls, increasing further dehydration. When your sugar molecules run out of water, that's when they "burn." In an alkaline solution, you won't really ever get "burnt sugar" flavors, unless you take it to very high temps. In an acidic solution, you'll get burnt flavors at a much lower temp.
If you don't want to mess with acids and bases, just take your sugar syrup up to around 300* or so and that should give you some nice burnt sugar notes. If you go much higher than 300* it'll become way too acrid.