
White balsamic vinegar is a pale, golden condiment vinegar of white grape must and white wine vinegar — mild and sweet-tart.
Everything darker brings the acidity and the color together, which a berry or cucumber drink cannot use. White wine vinegar with a pinch of sugar rebuilds it closely enough for a shrub.
Dark balsamic vinegar
A protected product made from reduced concentrated must, often with caramel coloring: darker, thicker and far richer. It brings sugar as well as acidity, and it stains — which is the whole reason a pale drink calls for the white one.
White wine vinegar
Sharper, drier and without the grape sweetness. Where a recipe wants brightness with a little sugar behind it, this alone reads sour.
It falls outside the protected "Aceto Balsamico di Modena" designation and is sold as a condimento — which tells you more about price and quality than the color does.
Sealed at room temperature it keeps for years. It is not protected the way the dark kind is, so bottles vary a lot in sweetness — taste a new one before you trust an old measurement.