I made a simple carrot puree last night doing the following:   Sweat off some carrots, onions, garlic and a bit of peeled apple Added a small amount of apple cider vinegar Added a bit of an alcoholic cider along with some water as a "stock" and simmered until soft. The alcoholic cider was a bit of an experiment.   Once blended, I noticed the puree was quite sweet (cider added a lot of sweetness along with the carrots), so I added a touch more apple cider vinegar to try balance and brighten things, especially considering the puree was a side to quite a rich protein.  The result was OK but not really what I wanted...I found the vinegar acidity did balance and lift the dish a bit, but I also found myself tasting the vinegar a bit too much. I wanted the acidity & brightness without actually tasting the apple cider vinegar.  I was left wondering if I should've rather added more cider vinegar earlier and let it cook through, or maybe just use less..or even just use a different type of vinegar?  So I guess my question more generally is: for this type of food, what is the best way to add some acidity to simply brighten things up without actually over-powering it? Any suggestions on other types of vinegars I could've used? 
Opinion and learned knowledge without doing searches for citations to back it up to follow:  Spices, including peppers have a history of being used to extend the life of foods including meats.  This is a false reputation and representation of that history, IMO.  The spices in reality were used in large quantities to cover up poor quality proteins and produce and hide the deficiencies and early stages of spoilage.  It hid these qualities only, it did little to nothing to reverse or slow them.  Under poor storage conditions 100 years ago a bite of pork might have turned your stomach to taste it at two days, but spice it up enough with peppers or a stout curry sauce and at four days you still might not have noticed.  This does not mean it will still not end up with you locked in the loo for a few hours or worse.  With improved meat and produce quality and storage capabilities today in most of the world (yes, really, even as much as many of us complain), this is no longer necessary. We make things spicy because we are used to the taste and like it.  But stories and traditions of it being a preservative continue.  Salt for instance is a preservative, but only in the quantities used in curing and pickling and such, not in the quantities we use to spice food.  That is for flavor, not to kill bacteria or extend the useful life of the food. 