I have some blueberry wine that ended up with a lot of alcohol and a
lot of acid, so I added some sugar (6%) to a sample and it tastes nice
as a sweet wine. I've never used potassium sorbate before. What are its
disadvantages? Does it give the wine any foul odor or taste? Does it
ever not work (you add the correct amount but the yeast starts kicking
anyway)? Is there any compelling reason not to use sorbate and instead
add sugar to the bottle after opening it?

Also, what's the difference between a sweet wine and a dessert wine? My
test with 6% sugar (TA is 0.9%) yielded a wine that tasted quite sweet,
but I see that some wines can have a lot more sugar than that. Are
sweet wines and dessert wines meant to be consumed in different
circumstances, at different times during a meal, etc?

Thanks in advance for any comments.