The real "vinegary" stuff was made by McClelland, a byproduct of their processing. It flashed off pretty quickly. Aged red Virginias tend to have more of a tang to them. Occasionally, some Virginias develop a more prominent sweetness to them after years of aging, or they don't.
I’ve noticed that tang vs sweetness in the same blend. Had a small jar of 5100 that had a citrus twinge to it, worked well blending with Haunted Bookshop.