Your soup needs a little vinegar

There comes a point in the life of many soups when they get a little sleepy. This happens especially often with soups that are creamy, starchy or — blessedly — both. Everything is humming along just fine. The onions are soft. The garlic is fragrant . The spices have bloomed. You taste a spoonful and think, Hmm . So you add another pinch of seasoning. You taste again. Still: Hmm. At this point, most of…